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Hencz AJ, Magony A, Thomas C, Kovacs K, Szilagyi G, Pal J, Sik A. Short-term hyperoxia-induced functional and morphological changes in rat hippocampus. Front Cell Neurosci 2024; 18:1376577. [PMID: 38686017 PMCID: PMC11057248 DOI: 10.3389/fncel.2024.1376577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 03/27/2024] [Indexed: 05/02/2024] Open
Abstract
Excess oxygen (O2) levels may have a stimulating effect, but in the long term, and at high concentrations of O2, it is harmful to the nervous system. The hippocampus is very sensitive to pathophysiological changes and altered O2 concentrations can interfere with hippocampus-dependent learning and memory functions. In this study, we investigated the hyperoxia-induced changes in the rat hippocampus to evaluate the short-term effect of mild and severe hyperoxia. Wistar male rats were randomly divided into control (21% O2), mild hyperoxia (30% O2), and severe hyperoxia groups (100% O2). The O2 exposure lasted for 60 min. Multi-channel silicon probes were used to study network oscillations and firing properties of hippocampal putative inhibitory and excitatory neurons. Neural damage was assessed using the Gallyas silver impregnation method. Mild hyperoxia (30% O2) led to the formation of moderate numbers of silver-impregnated "dark" neurons in the hippocampus. On the other hand, exposure to 100% O2 was associated with a significant increase in the number of "dark" neurons located mostly in the hilus. The peak frequency of the delta oscillation decreased significantly in both mild and severe hyperoxia in urethane anesthetized rats. Compared to normoxia, the firing activity of pyramidal neurons under hyperoxia increased while it was more heterogeneous in putative interneurons in the cornu ammonis area 1 (CA1) and area 3 (CA3). These results indicate that short-term hyperoxia can change the firing properties of hippocampal neurons and network oscillations and damage neurons. Therefore, the use of elevated O2 concentration inhalation in hospitals (i.e., COVID treatment and surgery) and in various non-medical scenarios (i.e., airplane emergency O2 masks, fire-fighters, and high altitude trekkers) must be used with extreme caution.
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Affiliation(s)
| | - Andor Magony
- Institute of Physiology, Medical School, University of Pécs, Pécs, Hungary
| | - Chloe Thomas
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Krisztina Kovacs
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Gabor Szilagyi
- Institute of Biochemistry and Medical Chemistry, Medical School, University of Pécs, Pécs, Hungary
| | - Jozsef Pal
- Institute of Physiology, Medical School, University of Pécs, Pécs, Hungary
| | - Attila Sik
- Institute of Physiology, Medical School, University of Pécs, Pécs, Hungary
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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Mehranpour M, Sani M, Beirami A, Hasanzadeh M, Taghizadeh M, Banihashemi M, Moghaddam MH, Fathi M, Vakili K, Yaghoobpoor S, Eskandari N, Abdollahifar MA, Bayat AH, Aliaghaei A, Heidari MH. Grafted Sertoli cells prevent neuronal cell death and memory loss induced by seizures. Metab Brain Dis 2023; 38:2735-2750. [PMID: 37851137 DOI: 10.1007/s11011-023-01309-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 10/04/2023] [Indexed: 10/19/2023]
Abstract
Epilepsy significantly reduces the patient's quality of life, and we still need to develop new therapeutic approaches to control it. Transplantation of cells such as Sertoli cells (SCs), having a potent ability to release a variety of growth and immunoprotective substances, have made them a potential candidate to deal with neurological diseases like epilepsy. Hence, this study aims to evaluate whether SCs transplant effectively protects the hippocampus astrocytes and neurons to oppose seizure damage. For this purpose, the effects of bilateral intrahippocampal transplantation of SCs were investigated on the rats with the pentylenetetrazol (PTZ) induced seizure. After one-month, post-graft analysis was performed regarding behavior, immunohistopathology, and the distribution of the hippocampal cells. Our findings showed SCs transplantation reduced astrogliosis, astrocytes process length, the number of branches, and intersections distal to the soma of the hippocampus in the seizure group. In rats with grafted SCs, there was a drop in the hippocampal caspase-3 expression. Moreover, the SCs showed another protective impact, as shown by an improvement in pyramidal neurons' number and spatial distribution. The findings suggested that SCs transplantation can potently modify astrocytes' reactivation and inflammatory responses.
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Affiliation(s)
- Maryam Mehranpour
- Hearing Disorders Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Genetics, Faculty of Biological Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Mojtaba Sani
- Department of Educational Neuroscience, Aras International Campus, University of Tabriz, Tabriz, Iran
| | - Amirreza Beirami
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maral Hasanzadeh
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Taghizadeh
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mobina Banihashemi
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Meysam Hassani Moghaddam
- Department of Anatomical Sciences, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran.
| | - Mobina Fathi
- Student Research Committee, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Kimia Vakili
- Student Research Committee, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shirin Yaghoobpoor
- Student Research Committee, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Neda Eskandari
- Department of Anatomical Sciences, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran
| | - Mohammad-Amin Abdollahifar
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir-Hossein Bayat
- Department of Neuroscience, School of Sciences and Advanced Technology in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Abbas Aliaghaei
- Hearing Disorders Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mohammad Hossain Heidari
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Pimenta J, Da Silva Oliveira B, Lima ALD, Machado CA, De Souza Barbosa Lacerda L, Rossi L, Queiroz-Junior CM, De Souza-Costa LP, Andrade ACSP, Gonçalves MR, Mota B, Marim FM, Aguiar RS, Guimarães PPG, Teixeira AL, Vieira LB, Guatimosim C, Teixeira MM, De Miranda AS, Costa VV. A suitable model to investigate acute neurological consequences of coronavirus infection. Inflamm Res 2023; 72:2073-2088. [PMID: 37837557 DOI: 10.1007/s00011-023-01798-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 09/06/2023] [Accepted: 09/13/2023] [Indexed: 10/16/2023] Open
Abstract
OBJECTIVE AND DESIGN The present study aimed to investigate the neurochemical and behavioral effects of the acute consequences after coronavirus infection through a murine model. MATERIAL Wild-type C57BL/6 mice were infected intranasally (i.n) with the murine coronavirus 3 (MHV-3). METHODS Mice underwent behavioral tests. Euthanasia was performed on the fifth day after infection (5 dpi), and the brain tissue was subjected to plaque assays for viral titration, ELISA, histopathological, immunohistochemical and synaptosome analysis. RESULTS Increased viral titers and mild histological changes, including signs of neuronal degeneration, were observed in the cerebral cortex of infected mice. Importantly, MHV-3 infection induced an increase in cortical levels of glutamate and calcium, which is indicative of excitotoxicity, as well as increased levels of pro-inflammatory cytokines (IL-6, IFN-γ) and reduced levels of neuroprotective mediators (BDNF and CX3CL1) in the mice brain. Finally, behavioral analysis showed impaired motor, anhedonia-like and anxiety-like behaviors in animals infected with MHV-3. CONCLUSIONS In conclusion, the data presented emulate many aspects of the acute neurological outcomes seen in patients with COVID-19. Therefore, this model may provide a preclinical platform to study acute neurological sequelae induced by coronavirus infection and test possible therapies.
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Affiliation(s)
- Jordane Pimenta
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Bruna Da Silva Oliveira
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Anna Luiza Diniz Lima
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Caroline Amaral Machado
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Larisse De Souza Barbosa Lacerda
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Leonardo Rossi
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Celso Martins Queiroz-Junior
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Luiz Pedro De Souza-Costa
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ana Claudia Santos Pereira Andrade
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Matheus Rodrigues Gonçalves
- Department of Microbiology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Bárbara Mota
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Fernanda Martins Marim
- Department of Genetics, Ecology and Evolution, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Renato Santana Aguiar
- Department of Genetics, Ecology and Evolution, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Pedro Pires Goulart Guimarães
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Antônio Lúcio Teixeira
- Department of Psychiatry and Behavioral Sciences, McGovern Medical Houston, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Luciene Bruno Vieira
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Cristina Guatimosim
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil
| | - Mauro Martins Teixeira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Aline Silva De Miranda
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil.
| | - Vivian Vasconcelos Costa
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil.
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Sabbir MG, Swanson M, Albensi BC. Loss of cholinergic receptor muscarinic 1 impairs cortical mitochondrial structure and function: implications in Alzheimer's disease. Front Cell Dev Biol 2023; 11:1158604. [PMID: 37274741 PMCID: PMC10233041 DOI: 10.3389/fcell.2023.1158604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 05/04/2023] [Indexed: 06/06/2023] Open
Abstract
Introduction: Cholinergic Receptor Muscarinic 1 (CHRM1) is a G protein-coupled acetylcholine (ACh) receptor predominantly expressed in the cerebral cortex. In a retrospective postmortem brain tissues-based study, we demonstrated that severely (≥50% decrease) reduced CHRM1 proteins in the temporal cortex of Alzheimer's patients significantly correlated with poor patient outcomes. The G protein-mediated CHRM1 signal transduction cannot sufficiently explain the mechanistic link between cortical CHRM1 loss and the appearance of hallmark Alzheimer's pathophysiologies, particularly mitochondrial structural and functional abnormalities. Therefore, the objective of this study was to analyze the molecular, ultrastructural, and functional properties of cortical mitochondria using CHRM1 knockout (Chrm1-/-) and wild-type mice to identify mitochondrial abnormalities. Methods: Isolated and enriched cortical mitochondrial fractions derived from wild-type and Chrm1-/- mice were assessed for respiratory deficits (oxygen consumption) following the addition of different substrates. The supramolecular assembly of mitochondrial oxidative phosphorylation (OXPHOS)-associated protein complexes (complex I-V) and cortical mitochondrial ultrastructure were investigated by blue native polyacrylamide gel electrophoresis and transmission electron microscopy (TEM), respectively. A cocktail of antibodies, specific to Ndufb8, Sdhb, Uqcrc2, Mtco1, and Atp5a proteins representing different subunits of complexes I-V, respectively was used to characterize different OXPHOS-associated protein complexes. Results: Loss of Chrm1 led to a significant reduction in cortical mitochondrial respiration (oxygen consumption) concomitantly associated with reduced oligomerization of ATP synthase (complex V) and supramolecular assembly of complexes I-IV (Respirasome). Overexpression of Chrm1 in transformed cells (lacking native Chrm1) significantly increased complex V oligomerization and respirasome assembly leading to enhanced respiration. TEM analysis revealed that Chrm1 loss led to mitochondrial ultrastructural defects and alteration in the tinctorial properties of cortical neurons causing a significant increase in the abundance of dark cortical neurons (Chrm1-/- 85% versus wild-type 2%). Discussion: Our findings indicate a hitherto unknown effect of Chrm1 deletion in cortical neurons affecting mitochondrial function by altering multiple interdependent factors including ATP synthase oligomerization, respirasome assembly, and mitochondrial ultrastructure. The appearance of dark neurons in Chrm1-/- cortices implies potentially enhanced glutamatergic signaling in pyramidal neurons under Chrm1 loss condition. The findings provide novel mechanistic insights into Chrm1 loss with the appearance of mitochondrial pathophysiological deficits in Alzheimer's disease.
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Affiliation(s)
- Mohammad Golam Sabbir
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
- Alzo Biosciences Inc, SanDiego, CA, United States
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
- Barry & Judy Silverman College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, United States
| | - Mamiko Swanson
- Alzo Biosciences Inc, SanDiego, CA, United States
- Barry & Judy Silverman College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, United States
| | - Benedict C. Albensi
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
- Barry & Judy Silverman College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, United States
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada
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Torshin VI, Kastyro IV, Reshetov IV, Kostyaeva MG, Popadyuk VI. The Relationship between p53-Positive Neurons and Dark Neurons in the Hippocampus of Rats after Surgical Interventions on the Nasal Septum. DOKL BIOCHEM BIOPHYS 2022; 502:30-35. [PMID: 35275303 DOI: 10.1134/s1607672922010094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/05/2021] [Accepted: 10/08/2021] [Indexed: 11/23/2022]
Abstract
The study evaluates the dependence of p53 protein expression on the appearance of dark neurons (DNs) in the hippocampus in rats during experimental modeling of septoplasty. Septoplasty simulation was carried out on 15 sexually mature male Wistar rats. We studied histological sections of the hippocampus stained with Nissl toluidine blue and antibodies to the p53 protein. In the CA1 subfield, the number of p53-positive neurons significantly increased on the 2nd, 4th (p < 0.001) and 6th days (p < 0.05). In the dynamics, the peak of the growth of p53 protein expression in the cytoplasm of CA1 and CA2 neurons fell on the 2-4th day after the operation, and on the 6th day the number of these neurons decreased (p < 0.001). In the cytoplasm of CA3 neurons in all periods after surgery, an increase in the expression of the p53 protein as compared to the control group was noted. In the CA1 pyramidal layer, the number of DNs decreased on the 6th day (p < 0.001). In CA2, after 2 days, a minimum of DNs as compared with the 4th day (p < 0.001) was noted. In CA3, on the 4th day, there was a peak in DNs as compared with the rest of the days (p < 0.001). A positive strong association was found in all periods of assessment and in all subfields of the hippocampus between an increase in the number of dark and p53-positive neurons. The appearance of dark and p53-positive neurons in the hippocampal formation in rats after simulating septoplasty are typical responses of nervous tissue to stress. It is obvious that the expression of the p53 protein is associated with the basophilia of the cytoplasm of neurons, their morpho-functional state. Presumably, the p53 protein can trigger not only the activation of damaged neurons in the hippocampus but also play a neuroprotective role. Upcoming studies should determine the role of the p53 protein in the further fate of damaged neurons in the pyramidal layer and differentiate the mechanisms of its expression.
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Affiliation(s)
- V I Torshin
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
| | - I V Kastyro
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia.
| | - I V Reshetov
- Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - M G Kostyaeva
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
| | - V I Popadyuk
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
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A 10-day mild treadmill exercise performed before an epileptic seizure alleviates oxidative injury in the skeletal muscle and brain tissues of the rats. MARMARA MEDICAL JOURNAL 2022. [DOI: 10.5472/marumj.1056192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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7
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Owjfard M, Bigdeli MR, Safari A, Namavar MR. Therapeutic Effects of Dimethyl Fumarate on the Rat Model of Brain Ischemia. BRAZ J PHARM SCI 2022. [DOI: 10.1590/s2175-97902022e19677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | - Mohammad Reza Namavar
- Shiraz University of Medical Sciences, Iran; Shiraz University of Medical Sciences, Iran
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Ozel AB, Cilingir-Kaya OT, Sener G, Ozbeyli D, Sen A, Sacan O, Yanardag R, Yarat A. Investigation of possible neuroprotective effects of some plant extracts on brain in bile duct ligated rats. J Food Biochem 2021; 45:e13835. [PMID: 34173678 DOI: 10.1111/jfbc.13835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/29/2021] [Accepted: 06/09/2021] [Indexed: 11/30/2022]
Abstract
This study aimed to investigate the possible neuroprotective effects of bitter melon (BM), chard, and parsley extracts on oxidative damage that may occur in the brain of rats with bile duct ligation (BDL)-induced biliary cirrhosis. It was observed that lipid peroxidation (LPO), sialic acid (SA), and nitric oxide (NO) levels increased; glutathione (GSH) levels, catalase (CAT) activity, and tissue factor (TF) activity decreased significantly in the BDL group. However, in groups with BDL given BM, chard, and parsley extracts LPO, SA, NO levels decreased; GSH levels and CAT activities increased significantly. No significant differences were observed between groups in total protein, glutathione-S-transferase, superoxide dismutase, and boron. Histological findings were supported by the biochemical results. BM, chard, and parsley extracts were effective in the regression of oxidant damage caused by cirrhosis in the brain tissues. PRACTICAL APPLICATIONS: Bitter melon (BM), chard, and parsley have antioxidant properties due to their bioactive compounds which are involved in scavenging free radicals, suppressing their production, and stimulating the production of endogenous antioxidant compounds. Since BM, chard, and parsley extracts were found to be effective in the regression of oxidant damage caused by cirrhosis in the brain tissues, these plant extracts may be an alternative in the development of different treatment approaches against brain damage in cirrhosis. At the same time, these species have been used as food by the people for many years. Therefore, they can be used safely as neuroprotective agents in treatment.
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Affiliation(s)
- Armagan Begum Ozel
- Department of Basic Medical Sciences, Biochemistry, Marmara University, Faculty of Dentistry, Istanbul, Turkey
| | | | - Goksel Sener
- Vocational School of Health Service, Fenerbahçe University, Istanbul, Turkey
| | - Dilek Ozbeyli
- Pathology Laboratory Techniques, Vocational School of Health Service, Marmara University, Istanbul, Turkey
| | - Ali Sen
- Department of Pharmacognosy, Marmara University, Faculty of Pharmacy, Istanbul, Turkey
| | - Ozlem Sacan
- Department of Chemistry, Istanbul University-Cerrahpasa, Faculty of Engineering, Istanbul, Turkey
| | - Refiye Yanardag
- Department of Chemistry, Istanbul University-Cerrahpasa, Faculty of Engineering, Istanbul, Turkey
| | - Aysen Yarat
- Department of Basic Medical Sciences, Biochemistry, Marmara University, Faculty of Dentistry, Istanbul, Turkey
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Namavar MR, Ghalavandi M, Bahmanpour S. The effect of glutathione and buserelin on the stereological parameters of the hypothalamus in the cyclophosphamide-treated mice. J Chem Neuroanat 2020; 110:101871. [PMID: 33039509 DOI: 10.1016/j.jchemneu.2020.101871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 02/02/2023]
Abstract
INTRODUCTION New anticancer drugs have increased the survival and fertility rates in young patients. These drugs (i.e., cyclophosphamide; Cyc) have some side effects on the hypothalamus and fertility. One possible chemical for reducing these side effects is thiol or GnRH agonist. This study aimed to evaluate the capability of these agents for reducing the cyclophosphamide effects on the hypothalamus. METHODS Sixty-three female mice were randomly assigned into seven groups. All groups including the control group had free access to water and mouse chow ad libitum. The sham group received normal saline. The Glu and Bus groups received glutathione (Glu) and buserelin (Bus) daily for 16 days, while the Cyc group received only cyclophosphamide as a single dose; the Cyc + Glu and Cyc + Bus groups, in addition to cyclophosphamide, received glutathione and buserelin, respectively. The volume of the hypothalamus, its neuron number, and dead neurons were evaluated using stereological methods. RESULTS There was no significant difference in the evaluated stereological parameters between the control and sham groups. However, the animals which received Cyc showed a decrease in the volume of the hypothalamus and its neuron number and density and an increase in cell death as compared with the control group. The treatment of the mice that received Cyc with Glu or Bus prevented these changes. CONCLUSION This study showed that both GnRH agonist and thiol preserved or improved structural changes in the hypothalamus caused by cyclophosphamide in mice, suggesting that using thiol and especially GnRH agonist along with chemotherapy drugs may have protective effects on fertility.
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Affiliation(s)
- M R Namavar
- Department of Anatomical Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran; Histomorphological and Stereology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran
| | - M Ghalavandi
- Department of Anatomical Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - S Bahmanpour
- Department of Anatomical Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran; Infertility Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
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Effects of nicorandil on neurobehavioral function, BBB integrity, edema and stereological parameters of the brain in the sub-acute phase of stroke in a rat model. J Biosci 2020. [DOI: 10.1007/s12038-020-0021-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Transient Morphological Alterations in the Hippocampus After Pentylenetetrazole-Induced Seizures in Rats. Neurochem Res 2018; 43:1671-1682. [DOI: 10.1007/s11064-018-2583-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/16/2018] [Accepted: 06/20/2018] [Indexed: 12/14/2022]
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12
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Riew TR, Shin YJ, Kim HL, Cho JM, Pak HJ, Lee MY. Spatiotemporal Progression of Microcalcification in the Hippocampal CA1 Region following Transient Forebrain Ischemia in Rats: An Ultrastructural Study. PLoS One 2016; 11:e0159229. [PMID: 27414398 PMCID: PMC4945069 DOI: 10.1371/journal.pone.0159229] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 06/29/2016] [Indexed: 11/19/2022] Open
Abstract
Calcification in areas of neuronal degeneration is a common finding in several neuropathological disorders including ischemic insults. Here, we performed a detailed examination of the onset and spatiotemporal profile of calcification in the CA1 region of the hippocampus, where neuronal death has been observed after transient forebrain ischemia. Histopathological examinations showed very little alizarin red staining in the CA1 pyramidal cell layer until day 28 after reperfusion, while prominent alizarin red staining was detected in CA1 dendritic subfields, particularly in the stratum radiatum, by 14 days after reperfusion. Electron microscopy using the osmium/potassium dichromate method and electron probe microanalysis revealed selective calcium deposits within the mitochondria of degenerating dendrites at as early as 7 days after reperfusion, with subsequent complete mineralization occurring throughout the dendrites, which then coalesced to form larger mineral conglomerates with the adjacent calcifying neurites by 14 days after reperfusion. Large calcifying deposits were frequently observed at 28 days after reperfusion, when they were closely associated with or completely engulfed by astrocytes. In contrast, no prominent calcification was observed in the somata of CA1 pyramidal neurons showing the characteristic features of necrotic cell death after ischemia, although what appeared to be calcified mitochondria were noted in some degenerated neurons that became dark and condensed. Thus, our data indicate that intrahippocampal calcification after ischemic insults initially occurs within the mitochondria of degenerating dendrites, which leads to the extensive calcification that is associated with ischemic injuries. These findings suggest that in degenerating neurons, the calcified mitochondria in the dendrites, rather than in the somata, may serve as the nidus for further calcium precipitation in the ischemic hippocampus.
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Affiliation(s)
- Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
| | - Yoo-Jin Shin
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
| | - Hong Lim Kim
- Integrative Research Support Center, Laboratory of Electron Microscope, College of Medicine, The Catholic University of Korea, Seoul, Korea, 137-701, Seoul, Korea
| | - Jeong Min Cho
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
| | - Ha-Jin Pak
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
- * E-mail:
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Tóth A, Kátai E, Kálmán E, Bogner P, Schwarcz A, Dóczi T, Sík A, Pál J. In vivo detection of hyperacute neuronal compaction and recovery by MRI following electric trauma in rats. J Magn Reson Imaging 2016; 44:814-22. [PMID: 26969965 DOI: 10.1002/jmri.25216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 02/16/2016] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To verify the following phenomenon in vivo using quantitative magnetic resonance imaging (MRI). Neuronal compression may occur following brain injuries in the cortex and hippocampus. As well being characterized by previous histological studies in rats, the majority of these neurons undergo hyperacute recovery rather than apoptotic death. MATERIALS AND METHODS Twenty male Wistar rats were assigned into injured or sham-injured groups (n = 10). The injured group underwent an electric trauma model to provoke compacted neuron formation. A T1 map was acquired prior to the injury and 10 T1 maps were acquired consecutively over a period of 2.5 hours after the injury, using a 3.0T scanner. Voxelwise statistical analyses were performed between timepoints. To enable comparison with the histological appearance of the compacted neurons, silver staining was performed on a sham-injured rat and five injured rats, 10, 40, 90, 150, and 300 minutes after the injury. RESULTS A significant (corrected P < 0.05) increase in average T1 from the preinjury (895.24 msec) to the first postinjury timepoint (T1 = 951.37 msec) was followed by a significant (corrected P < 0.05) decrease (return) up to the last postinjury timepoint (T1 = 913.16 msec) in the voxels of the cortex and hippocampus. No significant (corrected P < 0.05) change in T1 was found in the sham-injured group. CONCLUSION The spatial and temporal linkages between the MRI T1 changes and the histological findings suggest that neuronal compaction and recovery is associated with T1 alterations. MRI therefore offers the possibility of in vivo investigations of neuronal compaction and recovery. J. MAGN. RESON. IMAGING 2016;44:814-822.
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Affiliation(s)
- Arnold Tóth
- Department of Neurosurgery, University of Pécs, Pécs, Hungary.
| | - Emese Kátai
- Department of Laboratory Medicine, University of Pécs, Pécs, Hungary
| | - Endre Kálmán
- Department of Pathology, University of Pécs, Pécs, Hungary
| | | | - Attila Schwarcz
- Department of Neurosurgery, University of Pécs, Pécs, Hungary.,MTA-PTE Clinical Neuroscience MR Research Group, Pécs, Hungary
| | - Tamás Dóczi
- Department of Neurosurgery, University of Pécs, Pécs, Hungary.,MTA-PTE Clinical Neuroscience MR Research Group, Pécs, Hungary
| | - Attila Sík
- School of Clinical and Experimental Medicine College of Medical and Dental Sciences University of Birmingham, Birmingham, UK
| | - József Pál
- Department of Neurosurgery, University of Pécs, Pécs, Hungary.,School of Clinical and Experimental Medicine College of Medical and Dental Sciences University of Birmingham, Birmingham, UK
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Kim HL, Lee MY, Shin YJ, Song DW, Park J, Chang BS, Lee JH. Increased Expression of Osteopontin in the Degenerating Striatum of Rats Treated with Mitochondrial Toxin 3-Nitropropionic Acid: A Light and Electron Microscopy Study. Acta Histochem Cytochem 2015; 48:135-43. [PMID: 26633905 PMCID: PMC4652028 DOI: 10.1267/ahc.15010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/04/2015] [Indexed: 12/16/2022] Open
Abstract
The mycotoxin 3-nitropropionic acid (3NP) is an irreversible inhibitor that induces neuronal damage by inhibiting mitochondrial complex II. Neurodegeneration induced by 3NP, which is preferentially induced in the striatum, is caused by an excess influx and accumulation of calcium in mitochondria. Osteopontin (OPN) is a glycosylated phosphoprotein and plays a role in the regulation of calcium precipitation in the injured brain. The present study was designed to examine whether induction of OPN protein is implicated in the pathogenesis of 3NP-induced striatal neurodegeneration. We observed overlapping regional expression of OPN, the neurodegeneration marker Fluoro-Jade B, and the microglial marker ionized calcium-binding adaptor molecule 1 (Iba1) in the 3NP-lesioned striatum. OPN expression was closely associated with the mitochondrial marker NADH dehydrogenase (ubiquinone) flavoprotein 2 in the damaged striatum. In addition, immunoelectron microscopy demonstrated that OPN protein was specifically localized to the inner membrane and matrix of the mitochondria in degenerating striatal neurons, and cell fragments containing OPN-labeled mitochondria were also present within activated brain macrophages. Thus, our study revealed that OPN expression is associated with mitochondrial dysfunction produced by 3NP-induced alteration of mitochondrial calcium homeostasis, suggesting that OPN is involved in the pathogenesis of striatal degeneration by 3NP administration.
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Affiliation(s)
- Hong-Lim Kim
- Department of Veterinary Anatomy, College of Veterinary Medicine, Konkuk University
- Integrative Research Support Center, College of Medicine, Catholic University
| | - Mun-Yong Lee
- Department of Anatomy, College of Medicine, Catholic University
| | - Yoo-Jin Shin
- Department of Anatomy, College of Medicine, Catholic University
| | - Doo-Won Song
- Department of Veterinary Internal Medicine, College of Veterinary Medicine, Konkuk University
| | - Jieun Park
- Integrative Research Support Center, College of Medicine, Catholic University
| | | | - Jong-Hwan Lee
- Department of Veterinary Anatomy, College of Veterinary Medicine, Konkuk University
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Caron AM, Stephenson R. Sleep deprivation does not affect neuronal susceptibility to mild traumatic brain injury in the rat. Nat Sci Sleep 2015; 7:63-72. [PMID: 26124685 PMCID: PMC4482367 DOI: 10.2147/nss.s82888] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Mild and moderate traumatic brain injuries (TBIs) (and concussion) occur frequently as a result of falls, automobile accidents, and sporting activities, and are a major cause of acute and chronic disability. Fatigue and excessive sleepiness are associated with increased risk of accidents, but it is unknown whether prior sleep debt also affects the pathophysiological outcome of concussive injury. Using the "dark neuron" (DN) as a marker of reversible neuronal damage, we tested the hypothesis that acute (48 hours) total sleep deprivation (TSD) and chronic sleep restriction (CSR; 10 days, 6-hour sleep/day) affect DN formation following mild TBI in the rat. TSD and CSR were administered using a walking wheel apparatus. Mild TBI was administered under anesthesia using a weight-drop impact model, and the acute neuronal response was observed without recovery. DNs were detected using standard bright-field microscopy with toluidine blue stain following appropriate tissue fixation. DN density was low under home cage and sleep deprivation control conditions (respective median DN densities, 0.14% and 0.22% of neurons), and this was unaffected by TSD alone (0.1%). Mild TBI caused significantly higher DN densities (0.76%), and this was unchanged by preexisting acute or chronic sleep debt (TSD, 0.23%; CSR, 0.7%). Thus, although sleep debt may be predicted to increase the incidence of concussive injury, the present data suggest that sleep debt does not exacerbate the resulting neuronal damage.
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Affiliation(s)
- Aimee M Caron
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Richard Stephenson
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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16
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Vasil’ev DS, Tumanova NL, Zhuravin IA, Kim KK, Lukomskaya NY, Magazanik LG, Zaitsev AV. Morphofunctional changes in field CA1 of the rat hippocampus after pentylenetetrazole and lithium-pilocarpine induced seizures. J EVOL BIOCHEM PHYS+ 2015. [DOI: 10.1134/s0022093014060088] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Zaitsev AV, Kim KK, Vasilev DS, Lukomskaya NY, Lavrentyeva VV, Tumanova NL, Zhuravin IA, Magazanik LG. N-methyl-D-aspartate receptor channel blockers prevent pentylenetetrazole-induced convulsions and morphological changes in rat brain neurons. J Neurosci Res 2014; 93:454-65. [DOI: 10.1002/jnr.23500] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 12/25/2022]
Affiliation(s)
- Aleksey V. Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences; Saint Petersburg Russia
| | - Kira Kh. Kim
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences; Saint Petersburg Russia
| | - Dmitry S. Vasilev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences; Saint Petersburg Russia
| | - Nera Ya. Lukomskaya
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences; Saint Petersburg Russia
| | - Valeria V. Lavrentyeva
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences; Saint Petersburg Russia
| | - Natalia L. Tumanova
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences; Saint Petersburg Russia
| | - Igor A. Zhuravin
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences; Saint Petersburg Russia
| | - Lev G. Magazanik
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences; Saint Petersburg Russia
- Saint Petersburg State University; Saint Petersburg Russia
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18
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Martínez-Alfaro M, Cárabez-Trejo A, Sandoval-Zapata F, Morales-Tlalpan V, Palma-Tirado L. Subsurface cistern (SSC) proliferation in Purkinje cells of the rat cerebellum in response to acute and chronic exposure to paint thinner: A light and electron microscopy study. ACTA ACUST UNITED AC 2014; 66:323-32. [PMID: 24820124 DOI: 10.1016/j.etp.2014.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 03/17/2014] [Accepted: 04/15/2014] [Indexed: 11/25/2022]
Abstract
Intentional inhalation and occupational exposure are two ways humans are exposed to thinner, a widely employed solvent in industry. Inhalation of thinner induces toxic effects in various organs, with the cerebellum being one of the most affected structures of the CNS. The aim of this work was to describe specific structural alterations of cerebellum Purkinje cells in rats following exposure to thinner for 16 weeks. A histological analysis of the cerebellum of solvent-exposed rats revealed swollen Purkinje cell dendrites surrounded by empty space, and electronic microscopy showed an increase in the number of subsurface cisterns (SSCs) within their dendritic processes. After a period of non-exposure, the number of SSCs decreased without reaching normal levels, suggesting a degree of plasticity. Purkinje cell SSCs, which are derived from smooth endoplasmic reticulum, contain inositol trisphosphate receptors (IP3Rs), ryanodine receptors (RR), and a recently identified characteristic cluster of large conductance calcium-activated potassium (BKCa) channels. We found that SSCs in Purkinje cell dendrites were closely associated with mitochondria, and immunofluorescence microscopy showed higher levels of RR and calbindin receptors (CB), in Purkinje cells of exposed than normal rats. These changes are probably related to behavioral manifestations of cerebellar alterations, such as imbalance and ataxia, consistent with the suggested involvement of increases in SSCs in ataxia in rats and humans. This increase in SSCs, taken together with the localization of RR, IP3R and BKCa proteins in this structure, suggests altered intracellular calcium-buffering processes in the Purkinje cells of thinner-exposed rats.
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Affiliation(s)
- Minerva Martínez-Alfaro
- Departamento de Farmacia, Universidad de Guanajuato, Noria Alta, Guanajuato CP 36050, Mexico.
| | - Alfonso Cárabez-Trejo
- Instituto de Neurobiología UNAM Campus Juriquilla, Boulevard Juriquilla No. 3002, Querétaro CP 76230, Mexico.
| | - Francisca Sandoval-Zapata
- Instituto de Neurobiología UNAM Campus Juriquilla, Boulevard Juriquilla No. 3002, Querétaro CP 76230, Mexico
| | | | - Lourdes Palma-Tirado
- Instituto de Neurobiología UNAM Campus Juriquilla, Boulevard Juriquilla No. 3002, Querétaro CP 76230, Mexico
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Kovacs SK, Leonessa F, Ling GSF. Blast TBI Models, Neuropathology, and Implications for Seizure Risk. Front Neurol 2014; 5:47. [PMID: 24782820 PMCID: PMC3988378 DOI: 10.3389/fneur.2014.00047] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/26/2014] [Indexed: 12/31/2022] Open
Abstract
Traumatic brain injury (TBI) due to explosive blast exposure is a leading combat casualty. It is also implicated as a key contributor to war related mental health diseases. A clinically important consequence of all types of TBI is a high risk for development of seizures and epilepsy. Seizures have been reported in patients who have suffered blast injuries in the Global War on Terror but the exact prevalence is unknown. The occurrence of seizures supports the contention that explosive blast leads to both cellular and structural brain pathology. Unfortunately, the exact mechanism by which explosions cause brain injury is unclear, which complicates development of meaningful therapies and mitigation strategies. To help improve understanding, detailed neuropathological analysis is needed. For this, histopathological techniques are extremely valuable and indispensable. In the following we will review the pathological results, including those from immunohistochemical and special staining approaches, from recent preclinical explosive blast studies.
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Affiliation(s)
- S Krisztian Kovacs
- Laboratory of Neurotrauma, Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, MD , USA
| | - Fabio Leonessa
- Laboratory of Neurotrauma, Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, MD , USA
| | - Geoffrey S F Ling
- Laboratory of Neurotrauma, Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, MD , USA
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21
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Kaufmann W, Bolon B, Bradley A, Butt M, Czasch S, Garman RH, George C, Gröters S, Krinke G, Little P, McKay J, Narama I, Rao D, Shibutani M, Sills R. Proliferative and nonproliferative lesions of the rat and mouse central and peripheral nervous systems. Toxicol Pathol 2012; 40:87S-157S. [PMID: 22637737 DOI: 10.1177/0192623312439125] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Harmonization of diagnostic nomenclature used in the pathology analysis of tissues from rodent toxicity studies will enhance the comparability and consistency of data sets from different laboratories worldwide. The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of four major societies of toxicologic pathology to develop a globally recognized nomenclature for proliferative and nonproliferative lesions in rodents. This article recommends standardized terms for classifying changes observed in tissues of the mouse and rat central (CNS) and peripheral (PNS) nervous systems. Sources of material include academic, government, and industrial histopathology databases from around the world. Covered lesions include frequent, spontaneous, and aging-related changes as well as principal toxicant-induced findings. Common artifacts that might be confused with genuine lesions are also illustrated. The neural nomenclature presented in this document is also available electronically on the Internet at the goRENI website (http://www.goreni.org/).
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22
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Wells AJ, Vink R, Blumbergs PC, Brophy BP, Helps SC, Knox SJ, Turner RJ. A surgical model of permanent and transient middle cerebral artery stroke in the sheep. PLoS One 2012; 7:e42157. [PMID: 22848737 PMCID: PMC3407087 DOI: 10.1371/journal.pone.0042157] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 07/02/2012] [Indexed: 11/18/2022] Open
Abstract
Background Animal models are essential to study the pathophysiological changes associated with focal occlusive stroke and to investigate novel therapies. Currently used rodent models have yielded little clinical success, however large animal models may provide a more suitable alternative to improve clinical translation. We sought to develop a model of acute proximal middle cerebral artery (MCA) ischemic stroke in sheep, including both permanent occlusion and transient occlusion with reperfusion. Materials and Methods 18 adult male and female Merino sheep were randomly allocated to one of three groups (n = 6/gp): 1) sham surgery; 2) permanent proximal MCA occlusion (MCAO); or 3) temporary MCAO with aneurysm clip. All animals had invasive arterial blood pressure, intracranial pressure and brain tissue oxygen monitoring. At 4 h following vessel occlusion or sham surgery animals were killed by perfusion fixation. Brains were processed for histopathological examination and infarct area determination. 6 further animals were randomized to either permanent (n = 3) or temporary MCAO (n = 3) and then had magnetic resonance imaging (MRI) at 4 h after MCAO. Results Evidence of ischemic injury in an MCA distribution was seen in all stroke animals. The ischemic lesion area was significantly larger after permanent (28.8%) compared with temporary MCAO (14.6%). Sham animals demonstrated no evidence of ischemic injury. There was a significant reduction in brain tissue oxygen partial pressure after permanent vessel occlusion between 30 and 210 mins after MCAO. MRI at 4 h demonstrated complete proximal MCA occlusion in the permanent MCAO animals with a diffusion deficit involving the whole right MCA territory, whereas temporary MCAO animals demonstrated MRA evidence of flow within the right MCA and smaller predominantly cortical diffusion deficits. Conclusions Proximal MCAO can be achieved in an ovine model of stroke via a surgical approach. Permanent occlusion creates larger infarct volumes, however aneurysm clip application allows for reperfusion.
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Affiliation(s)
- Adam J Wells
- Adelaide Centre for Neuroscience Research, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia.
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Wohlsein P, Deschl U, Baumgärtner W. Nonlesions, unusual cell types, and postmortem artifacts in the central nervous system of domestic animals. Vet Pathol 2012; 50:122-43. [PMID: 22692622 DOI: 10.1177/0300985812450719] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the central nervous system (CNS) of domestic animals, numerous specialized normal structures, unusual cell types, findings of uncertain or no significance, artifacts, and various postmortem alterations can be observed. They may cause confusion for inexperienced pathologists and those not specialized in neuropathology, leading to misinterpretations and wrong diagnoses. Alternatively, changes may mask underlying neuropathological processes. "Specialized structures" comprising the hippocampus and the circumventricular organs, including the vascular organ of the lamina terminalis, subfornical organ, subcommissural organ, pineal gland, median eminence/neurohypophyseal complex, choroid plexus, and area postrema, are displayed. Unusual cell types, including cerebellar external germinal cells, CNS progenitor cells, and Kolmer cells, are presented. In addition, some newly recognized cell types as of yet incompletely understood significance and functionality, such as synantocytes and aldynoglia, are introduced and described. Unusual reactive astrocytes in cats, central chromatolysis, neuronal vacuolation, spheroids, spongiosis, satellitosis, melanosis, neuromelanin, lipofuscin, polyglucosan bodies, and psammoma bodies may represent incidental findings of uncertain or no significance and should not be confused with significant microscopic changes. Auto- and heterolysis as well as handling and histotechnological processing may cause postmortem morphological changes of the CNS, including vacuolization, cerebellar conglutination, dark neurons, Buscaino bodies, freezing, and shrinkage artifacts, all of which have to be differentiated from genuine lesions. Postmortem invasion of micro-organisms should not be confused with intravital infections. Awareness of these different changes and their recognition are a prerequisite for identifying genuine lesions and may help to formulate a professional morphological and etiological diagnosis.
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Affiliation(s)
- P Wohlsein
- Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany.
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Kovács B, Bukovics P, Gallyas F. Morphological effects of transcardially perfused SDS on the rat brain. Biol Cell 2012; 99:425-32. [PMID: 17371297 DOI: 10.1042/bc20060128] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION For explanation of the formation of 'dark' neurons, an enigmatic phenomenon in neuropathology, we hypothesized recently that all spaces between the ultrastructural elements visible in the traditional transmission electron microscope are filled with a gel structure that stores free energy in the form of non-covalent interactions, is continuous in the whole soma-dendrite domains of neurons, and is capable of whole-cell phase transition. This hypothesis was deduced from the fact that 'dark' neurons can be formed, even under conditions extremely unfavourable for enzyme-mediated biochemical processes, if initiated by a physical damage. In order to gain further information on this gel structure, we perfused transcardially rats for 5 min with physiological saline containing 1 mM SDS before the perfusion of a fixative for electron microscopy. RESULTS Dramatic compaction of visibly intact ultrastructural elements was caused in the whole soma-dendrite domains of thinly scattered neurons ('dark' neurons), whereas substantial cytoplasmic swelling and patchy ultrastructural disintegration occurred in numerous other neurons ('light' neurons). Similar morphological changes were observed in scattered astrocytes, oligodendrocytes, pericytes and endothelial cells. CONCLUSIONS These observations: (i) support the existence of the above intracellular gel structure in neurons; (ii) allow the conclusion that this gel structure is present in the form of an ubiquitous trabecular network surrounded by a confluent system of fluid cytoplasm; (iii) draw attention to the possibility that the previous two statements also apply to other cell types of the brain tissue; and (iv) suggest that pressure-induced direct channels exist between neurons and astrocytes.
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Affiliation(s)
- Betti Kovács
- Department of Neurosurgery, Pécs University, Pécs, Rét utca 2, Hungary
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Yamada N, Sasaki S, Ishii H, Sato J, Kanno T, Wako Y, Tsuchitani M. Dark cell change of the cerebellar Purkinje cells induced by terbutaline under transient disruption of the blood-brain barrier in adult rats: morphological evaluation. J Appl Toxicol 2011; 32:790-5. [PMID: 21618259 DOI: 10.1002/jat.1690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 04/07/2011] [Accepted: 04/07/2011] [Indexed: 11/06/2022]
Abstract
This study aimed to establish a cerebellar degeneration animal model and to characterize the dark cell change of Purkinje cells. We hypothesized that terbutaline, a β2-adrenoceptor agonist, induces cerebellar degeneration not only in neonatal rats, but also in adult rats. Nine-week-old adult male Sprague-Dawley rats were anesthetized and infused with 25% mannitol via the left common carotid artery. Thirty seconds later, terbutaline was infused via the same artery. Dark-stained Purkinje cells were observed in the entire cerebellum on day 3. Prominent Bergmann glial cells accompanied by swelling of the glial processes were present, and were closely associated with the dark-stained Purkinje cells. These findings were found continuously throughout day 30. Ultrastructurally, dilated Golgi vesicles and/or endoplasmic reticulum and large lamella bodies were present in both severely changed and slightly changed Purkinje cells. Bergmann glial cells in the area of synaptic contacts of the severely changed Purkinje cells showed swelling. The Bergmann glial process in close contact with the slightly changed Purkinje cell dendrite in molecular layer showed slight swelling, and large lamella bodies in the dendrite were observed close to the dendritic spines. These findings may suggest that terbutaline induced a failure of Bergmann glial cell and resulted in dark cell degeneration of the Purkinje cells due to glutamate excitotoxicity.
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Affiliation(s)
- Naoaki Yamada
- Pathology Division, Mitsubishi Chemical Medience Corporation, 14 Sunayama, Kamisu-shi, Ibaraki, 314-0255, Japan.
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Florea A, Puică C, Vinţan M, Benga I, Crăciun C. Electrophysiological and structural aspects in the frontal cortex after the bee (Apis mellifera) venom experimental treatment. Cell Mol Neurobiol 2011; 31:701-14. [PMID: 21359542 DOI: 10.1007/s10571-011-9667-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 02/14/2011] [Indexed: 11/26/2022]
Abstract
The aim of this study is to evaluate the bioelectrical and structural-functional changes in frontal cortex after the bee venom (BV) experimental treatments simulating both an acute envenomation and a subchronic BV therapy. Wistar rats were subcutaneously injected once with three different BV doses: 700 μg/kg (T(1) group), 2100 μg/kg (T(3) group), and 62 mg/kg (sublethal dose-in T(SL) group), and repeated for 30 days with the lowest dose (700 μg/kg-in T(S) group). BV effects were assessed by electrophysiological, histological, histochemical, and ultrastructural methods. Single BV doses produced discharges of negative and biphasic sharp waves, and epileptiform spike-wave complexes. The increasing frequency of these elements suggested a dose-dependent neuronal hyperexcitation or irritation. As compared to the lower doses, the sublethal dose was responsible for a pronounced toxic effect, confirmed by ultrastructural data in both neurons and glial cells that underwent extensive, irreversible changes, triggering the cellular death. Subchronic BV treatment in T(S) group resulted in a slower frequency and increased amplitude of cortical activity suggesting neuronal loss. However, neurons were still stimulated by the last BV dose. Structural-functional data showed a reduced cellular density in frontal cortex of animals in this group, while the remaining neurons displayed both specific (stimulation of neuronal activity) and unspecific modifications (moderate alterations to necrotic phenomena). Molecular mechanisms involved in BV interactions with the nervous tissue are also discussed. We consider all these data very important for clinicians who manage patients with multiple bee stings, or who intend to set an appropriate BV therapy.
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Affiliation(s)
- Adrian Florea
- Department of Cell and Molecular Biology, "Iuliu Haţieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania.
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Shin YJ, Lim Kim H, Choi JS, Choi JY, Cha JH, Lee MY. Osteopontin: Correlation with phagocytosis by brain macrophages in a rat model of stroke. Glia 2010; 59:413-23. [DOI: 10.1002/glia.21110] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 10/21/2010] [Indexed: 11/12/2022]
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Gallyas F. A cytoplasmic gel network capable of mediating the conversion of chemical energy to mechanical work in diverse cell processes: a speculation. ACTA BIOLOGICA HUNGARICA 2010; 61:367-79. [PMID: 21112829 DOI: 10.1556/abiol.61.2010.4.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Enigmatic morphological features of the formation and fate of "dark" (hyper-basophilic, hyper-argyrophilic and hyper-electrondense) neurons suggest that the mechanical work causing their dramatic shrinkage (whole-cell ultrastructural compaction) is done by a previously "unknown" ultrastructural component residing in the spaces between their "known" (i.e. visible in the conventional transmission electron microscopy) ultrastructural constituents. Embedment-free section electron microscopy revealed in these spaces the existence of a continuous network of gel microdomains, which is embedded in a continuous network of fluid-filled lacunae. We gathered experimental facts suggesting that this gel network is capable of a volume-reducing phase-transition (an established physico-chemical phenomenon), which could be the motor of the whole-cell ultrastructural compaction. The present paper revisits our relevant observations and speculates how such a continuous whole-cell gel network can do both whole-cell and compartmentalized mechanical work.
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Affiliation(s)
- F Gallyas
- Department of Neurosurgery, Faculty of Medicine, University of Pécs, Pécs, Hungary.
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Takács E, Nyilas R, Szepesi Z, Baracskay P, Karlsen B, Røsvold T, Bjørkum AA, Czurkó A, Kovács Z, Kékesi AK, Juhász G. Matrix metalloproteinase-9 activity increased by two different types of epileptic seizures that do not induce neuronal death: a possible role in homeostatic synaptic plasticity. Neurochem Int 2010; 56:799-809. [PMID: 20303372 DOI: 10.1016/j.neuint.2010.03.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 03/08/2010] [Accepted: 03/10/2010] [Indexed: 01/26/2023]
Abstract
Matrix metalloproteases (MMPs) degrade or modify extracellular matrix or membrane-bound proteins in the brain. MMP-2 and MMP-9 are activated by treatments that result in a sustained neuronal depolarization and are thought to contribute to neuronal death and structural remodeling. At the synapse, MMP actions on extracellular proteins contribute to changes in synaptic efficacy during learning paradigms. They are also activated during epileptic seizures, and MMP-9 has been associated with the establishment of aberrant synaptic connections after neuronal death induced by kainate treatment. It remains unclear whether MMPs are activated by epileptic activities that do not induce cell death. Here we examine this point in two animal models of epilepsy that do not involve extensive cell damage. We detected an elevation of MMP-9 enzymatic activity in cortical regions of secondary generalization after focal seizures induced by 4-aminopyridine (4-AP) application in rats. Pro-MMP-9 levels were also higher in Wistar Glaxo Rijswijk (WAG/Rij) rats, a genetic model of generalized absence epilepsy, than they were in Sprague-Dawley rats, and this elevation was correlated with diurnally occurring spike-wave-discharges in WAG/Rij rats. The increased enzymatic activity of MMP-9 in these two different epilepsy models is associated with synchronized neuronal activity that does not induce widespread cell death. In these epilepsy models MMP-9 induction may therefore be associated with functions such as homeostatic synaptic plasticity rather than neuronal death.
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Affiliation(s)
- Eszter Takács
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, Budapest, Hungary.
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Baracskay P, Kiglics V, Kékesi KA, Juhász G, Czurkó A. Status epilepticus affects the gigantocellular network of the pontine reticular formation. BMC Neurosci 2009; 10:133. [PMID: 19912649 PMCID: PMC2781816 DOI: 10.1186/1471-2202-10-133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 11/13/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The impairment of the pontine reticular formation (PRF) has recently been revealed to be histopathologically connected with focal-cortical seizure induced generalized convulsive status epilepticus. To elucidate whether the impairment of the PRF is a general phenomenon during status epilepticus, the focal-cortical 4-aminopyridine (4-AP) application was compared with other epilepsy models. The presence of "dark" neurons in the PRF was investigated by the sensitive silver method of Gallyas in rats sacrificed at 3 h after focal 4-AP crystal or systemic 4-AP, pilocarpine, or kainic acid application. The behavioral signs of the developing epileptic seizures were scored in all rats. The EEG activity was recorded in eight rats. RESULTS Regardless of the initiating drug or method of administration, "dark" neurons were consistently found in the PRF of animals entered the later phases of status epilepticus. EEG recordings demonstrated the presence of slow oscillations (1.5-2.5 Hz) simultaneously with the appearance of giant "dark" neurons in the PRF. CONCLUSION We argue that the observed slow oscillation corresponds to the late periodic epileptiform discharge phase of status epilepticus, and that the PRF may be involved in the progression of status epilepticus.
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Affiliation(s)
- Péter Baracskay
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
- Institute of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary
| | - Viola Kiglics
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Katalin A Kékesi
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
- Department of Physiology and Neurobiology, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Gábor Juhász
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - András Czurkó
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
- Institute of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary
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Masuda H, Ushiyama A, Takahashi M, Wang J, Fujiwara O, Hikage T, Nojima T, Fujita K, Kudo M, Ohkubo C. Effects of 915 MHz electromagnetic-field radiation in TEM cell on the blood-brain barrier and neurons in the rat brain. Radiat Res 2009; 172:66-73. [PMID: 19580508 DOI: 10.1667/rr1542.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The aim of this study was to determine whether albumin leakage and dark neurons were present in rat brains 14 and 50 days after a single 2-h exposure to a 915 MHz electromagnetic field, as reported by Salford et al. (Environ. Health Perspect. 111, 881-883, 203). Sixty-four male F344 rats (12 weeks old) were exposed to a 915 MHz electromagnetic field at whole-body average specific absorption rates of 0, 0.02, 0.2 and 2.0 W/kg in TEM cells for 2 h, following the protocol reported by Salford et al. The brains were examined histologically and immunohistochemically. No albumin immunoreactivity was observed in the exposed groups. In addition, dark neurons, assessed using hematoxylin and eosin staining, were rarely present, with no statistically significant difference between exposed and sham-exposed animals. This study thus failed to confirm the results of Salford et al.
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Affiliation(s)
- Hiroshi Masuda
- Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako-shi, Saitama 351-0197, Japan.
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Supravital microwave experiments support that the formation of “dark” neurons is propelled by phase transition in an intracellular gel system. Brain Res 2009; 1270:152-6. [DOI: 10.1016/j.brainres.2009.03.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 03/12/2009] [Accepted: 03/12/2009] [Indexed: 11/20/2022]
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Aldehyde fixation is not necessary for the formation of "dark" neurons. Acta Neuropathol 2008; 116:463-4. [PMID: 18696090 DOI: 10.1007/s00401-008-0424-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 07/10/2008] [Accepted: 08/06/2008] [Indexed: 10/21/2022]
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Gallyas F, Kiglics V, Baracskay P, Juhász G, Czurkó A. The mode of death of epilepsy-induced "dark" neurons is neither necrosis nor apoptosis: an electron-microscopic study. Brain Res 2008; 1239:207-15. [PMID: 18801347 DOI: 10.1016/j.brainres.2008.08.069] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 08/21/2008] [Accepted: 08/25/2008] [Indexed: 10/21/2022]
Abstract
Morphological aspects of the formation and fate of neurons that underwent dramatic ultrastructural compaction ("dark" neurons) induced by 4-aminopyridine epilepsy were compared in an excitotoxic and a neighboring normal-looking area of the rat brain cortex. In the excitotoxic area, the later the ultrastructural compaction began after the outset of epilepsy, the higher the degree of mitochondrial swelling and ribosomal sequestration were; a low proportion of the affected neurons recovered in 1 day; the others were removed from the tissue through a necrotic-like sequence of ultrastructural changes (swelling of the cell, gradual disintegration of the intracellular organelles and dispersion of their remnants into the surroundings through large gaps in the plasma and nuclear membranes). In the normal-looking area, the ultrastructural elements in the freshly-formed "dark" neurons were apparently normal; most of them recovered in 1 day; the others were removed from the tissue through an apoptotic-like sequence of ultrastructural changes (the formation of membrane-bound, electrondense, compact cytoplasmic protrusions, and their braking up into membrane-bound, electrondense, compact fragments, which were swallowed by phagocytotic cells). Since these ultrastructural features differ fundamentally from those characteristic of necrosis, it seems logical that, in stark contrast with the prevailing conception, the cause of death of the epilepsy-induced "dark" neurons in the normal-looking cortical area cannot be necrosis. An apoptotic origin can also be precluded by virtue of the absence of its characteristics. As regards the excitotoxic environment, it is assumed that pathobiochemical processes in it superimpose a necrotic-like removal process on already dead "dark" neurons.
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Affiliation(s)
- Ferenc Gallyas
- Department of Neurosurgery, Faculty of Medicine, University of Pécs, H-7623 Pécs, Rét utca 2, Hungary.
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Baracskay P, Szepesi Z, Orbán G, Juhász G, Czurkó A. Generalization of seizures parallels the formation of "dark" neurons in the hippocampus and pontine reticular formation after focal-cortical application of 4-aminopyridine (4-AP) in the rat. Brain Res 2008; 1228:217-28. [PMID: 18602900 DOI: 10.1016/j.brainres.2008.06.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 06/13/2008] [Accepted: 06/13/2008] [Indexed: 10/21/2022]
Abstract
Distribution and time course of the occurrence of "dark" neurons were compared with the EEG activity and behavior of rats during 4-aminopyridine (4-AP) induced epileptic seizures. A crystal of the K(+) channel blocker 4-AP (0.5 mg/kg) was placed onto the exposed parieto-occipital cortex of Halothane-anesthetized rats for 40 min. Thereafter, the anesthesia was discontinued and the behavioral signs of the epileptic seizure activity were observed. The presence of "dark" neurons was demonstrated by the sensitive silver method of Gallyas in rats sacrificed at 0, 3 and 6 h after the end of the 4-AP crystal application. The EEG activity was recorded in the rats with longer survival times. The EEG analysis revealed the generalization of the epileptic seizures. We found that the formation of "dark" neurons in the hippocampus and the pontine reticular formation paralleled the generalization of the seizures.
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Affiliation(s)
- Péter Baracskay
- Institute of Biology, Faculty of Natural Sciences, Eötvös Loránd University, H-1117 Budapest, Hungary
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36
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Rosenblum WI. Cytotoxic edema: monitoring its magnitude and contribution to brain swelling. J Neuropathol Exp Neurol 2007; 66:771-8. [PMID: 17805007 DOI: 10.1097/nen.0b013e3181461965] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Cytotoxic edema (CytE) is an increment in total brain water produced when the excess water swells cells rather than expanding the extracellular space. CytE contributes to brain swelling with a resultant increase of intracranial pressure (ICP). However, questions remain concerning the magnitude of the contribution made by CytE to raised ICP and the ability of CytE by itself to produce lethal levels of ICP that result in brainstem herniation. These questions exist because there are pitfalls in estimating the magnitude of CytE and hence its contribution to ICP using either electron microscopy or in vivo surrogates for CytE such as impedance measurements or the apparent diffusion coefficient. Correlation of these measures has been made during CytE. However, the literature provides reasons to question whether any of these surrogates for CytE can give accurate quantitative measures of CytE. At present, there is little evidence to indicate that CytE can, by itself, raise ICP to lethal levels. However, because CytE can raise ICP, it is of interest to develop treatments to prevent or reduce CytE even though currently available data do not yet provide an established mechanistic basis upon which to base such therapy.
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Affiliation(s)
- William I Rosenblum
- Virginia Commonwealth University Medical Center-Medical College of Virginia Campus, Richmond, VA, USA.
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37
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Kövesdi E, Pál J, Gallyas F. The fate of “dark” neurons produced by transient focal cerebral ischemia in a non-necrotic and non-excitotoxic environment: Neurobiological aspects. Brain Res 2007; 1147:272-83. [PMID: 17349980 DOI: 10.1016/j.brainres.2007.02.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 02/05/2007] [Accepted: 02/06/2007] [Indexed: 11/16/2022]
Abstract
BACKGROUND INFORMATION We recently proposed novel neurobiological ideas for discussion regarding the common nature (malfunction of a physicochemical phenomenon genetically programmed for the morphological execution of ontogenetic apoptosis), mechanism of formation (phase transition in an intraneuronal gel structure) and mode of death (neither necrosis nor apoptosis) of "dark" neurons. These ideas were deduced from morphological changes in neurons found in a visually undamaged environment after in vivo or postmortem mechanical or electric injuries and after hypoglycemia. OBJECTIVE In search of further support, this paper revisits these ideas in the case of transient focal cerebral ischemia by investigating the light- and electron-microscopic changes produced in neurons by a 1-h occlusion of the rat middle cerebral artery in non-necrotic and non-excitotoxic tissue areas, where extraneuronal pathological processes may not influence the intraneuronal events. RESULTS In the first hour after restoration of circulation, the soma-dendrite domains of "dark" neurons displayed hyperbasophilia, hyperargyrophilia, hyper-electron density and a dramatic compaction of ultrastructural elements. Between 1 h and 1 day of the restored circulation, the degree of ultrastructural compaction decreased and mitochondrion-derived membranous whorls appeared in several "dark" neurons indicating recovery. Further, the cytoplasm of scattered neurons manifesting the apoptotic condensation pattern of the nuclear chromatin displayed the same morphological features as those of the freshly produced "dark" neurons. After 1 day of restored circulation, both the non-recovering "dark" neurons and the apoptotic neurons fell into membrane-bound, compact and electron-dense fragments, which were subsequently engulfed by phagocytotic cells. CONCLUSION These observations support each of the ideas mentioned above.
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Affiliation(s)
- Erzsébet Kövesdi
- Department of Neurosurgery, Pécs University, H-7624 Pécs, Rét utca 2, Hungary
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38
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Szolnoki Z. A dynamically changing intracellular water network serves as a universal regulator of the cell: the water-governed cycle. Biochem Biophys Res Commun 2007; 357:331-4. [PMID: 17420007 DOI: 10.1016/j.bbrc.2007.03.161] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2007] [Accepted: 03/27/2007] [Indexed: 10/23/2022]
Abstract
The functioning of enzymes and protein folding are well known to be assisted by the surrounding chaperoning water molecules, which are connected to the protein via non-covalent, dynamically changing chemical bonds. A molecular intracellular network of weak non-covalent connections may be presumed to exist in living cells. The roles of such non-covalent networks are examined in terms of a molecular model which postulates a universal enzyme and biochemical mechanism regulating the maintenance of chemical stability in living cells.
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Affiliation(s)
- Zoltán Szolnoki
- Department of Neurology and Neurophysiology, Pándy Kálmán County Hospital, H-5600 Békéscsaba, Pipacs köz 9, Hungary.
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39
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Ooigawa H, Nawashiro H, Fukui S, Otani N, Osumi A, Toyooka T, Shima K. The fate of Nissl-stained dark neurons following traumatic brain injury in rats: difference between neocortex and hippocampus regarding survival rate. Acta Neuropathol 2006; 112:471-81. [PMID: 16858608 DOI: 10.1007/s00401-006-0108-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 06/20/2006] [Accepted: 06/26/2006] [Indexed: 10/24/2022]
Abstract
We studied the fate of Nissl-stained dark neurons (N-DNs) following traumatic brain injury (TBI). N-DNs were investigated in the cerebral neocortex and the hippocampus using a rat lateral fluid percussion injury model. Nissl stain, acid fuchsin stain and immunohistochemistry with phosphorylated extracellular signal-regulated protein kinase (pERK) antibody were used in order to assess posttraumatic neurons. In the neocortex, the number of dead neurons at 24 h postinjury was significantly less than that of the observed N-DNs in the earlier phase. Only a few N-DNs increased their pERK immunoreactivity. On the other hand, in the hippocampus the number of dead neurons was approximately the same number as that of the N-DNs, and most N-DNs showed an increased pERK immunoreactivity. These data suggest that not all N-DNs inevitably die especially in the neocortex after TBI. The fate of N-DNs is thus considered to differ depending on brain subfields.
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Affiliation(s)
- Hidetoshi Ooigawa
- Department of Neurosurgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
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40
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Gallyas F, Gasz B, Szigeti A, Mázló M. Pathological circumstances impair the ability of "dark" neurons to undergo spontaneous recovery. Brain Res 2006; 1110:211-20. [PMID: 16872583 DOI: 10.1016/j.brainres.2006.06.078] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 06/20/2006] [Accepted: 06/22/2006] [Indexed: 11/17/2022]
Abstract
The effects of dehydrating drugs (furosemide, mannitol and glycerine), potassium channel modulators (tetraethylammonium chloride, 5-hydroxydecanoic acid Na salt, minoxidil and pinacidil), sodium channel modulators (veratridine, brevetoxin-9, 5-(N,N-dimethyl)amiloride and benzamil-HCl) and mitochondrial enzyme inhibitors (3-nitropropionic acid, 2,4-dinitrophenol and chloramphenicol) on the fate of electrically produced "dark" hippocampal dentate granule neurons were investigated. All but one (chloramphenicol) of these bioactive reagents substantially retarded the recovery and increased the death rate of such "dark" neurons. As concerns the dehydrating drugs and ion channel modulators, these effects are considered to be consequences of the fact that relatively large volumes (more than half of the original cell volume) of cytoplasmic fluid (water molecules, inorganic ions and metabolites) leave the affected cells through passive pores within a few minutes. The effects of the mitochondrial enzyme inhibitors appear to indicate that restoration of the original cell volume (recovery) demands metabolic (enzyme-mediated) energy. All these features support our previous assumption that the exogenous circumstances existing acutely after the formation of "dark" neurons in neurological diseases decide whether they will recover or die.
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41
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Pál J, Tóth Z, Farkas O, Kellényi L, Dóczi T, Gallyas F. Selective induction of ultrastructural (neurofilament) compaction in axons by means of a new head-injury apparatus. J Neurosci Methods 2006; 153:283-9. [PMID: 16384604 DOI: 10.1016/j.jneumeth.2005.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 11/10/2005] [Accepted: 11/10/2005] [Indexed: 11/25/2022]
Abstract
A new weight-drop head-injury apparatus is described that can produce a momentary depression of predetermined depth at a predetermined site of the elastic calvaria of scalped young adult rats. In Wistar rats weighing about 200 g, a 0.75-mm deep calvaria depression immediately caused ultrastructural (neurofilament) compaction in many long axon segments, which were diffusely scattered among non-compacted axons in a well-defined area of cortical layers IV and V under the impact site. Apart from these morphological changes and swollen astrocytic processes in their vicinity, the brain tissue appeared non-impaired. The blood pressure, intracranial pressure, heart rate and respiration rate had returned to the normal range in 1 min. Diffuse axonal swelling caused by impaired axonal transport, ultrastructural compaction in neuronal soma-dendrite domains, impression fracture and subarachnoid or subdural hemorrhages were observed only in rats with a calvaria depression of 1mm or more. All these features create favorable circumstances for study of various problems that are closely related to the ultrastructural (neurofilament) compaction in axons, such as the fate of the affected axons.
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Affiliation(s)
- József Pál
- Clinical Neuroscience Research Group of the Hungarian Academy of Sciences, Pécs University, Rét utca 2, H-7623 Pécs, Hungary.
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42
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Thornton E, Vink R, Blumbergs PC, Van Den Heuvel C. Soluble amyloid precursor protein α reduces neuronal injury and improves functional outcome following diffuse traumatic brain injury in rats. Brain Res 2006; 1094:38-46. [PMID: 16697978 DOI: 10.1016/j.brainres.2006.03.107] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 03/14/2006] [Accepted: 03/23/2006] [Indexed: 11/23/2022]
Abstract
Amyloid precursor protein (APP) has previously been shown to increase following traumatic brain injury (TBI). Whereas a number of investigators assume that increased APP may lead to the production of neurotoxic Abeta and be deleterious to outcome, the soluble alpha form of APP (sAPPalpha) is a product of the non-amyloidogenic cleavage of amyloid precursor protein that has previously been shown in vitro to have many neuroprotective and neurotrophic functions. However, no study to date has addressed whether sAPPalpha may be neuroprotective in vivo. The present study examined the effects of in vivo, posttraumatic sAPPalpha administration on functional motor outcome, cellular apoptosis, and axonal injury following severe impact-acceleration TBI in rats. Intracerebroventricular administration of sAPPalpha at 30 min posttrauma significantly improved motor outcome compared to vehicle-treated controls as assessed using the rotarod task. Immunohistochemical analysis using antibodies directed toward caspase-3 showed that posttraumatic treatment with sAPPalpha significantly reduced the number of apoptotic neuronal perikarya within the hippocampal CA3 region and within the cortex 3 days after injury compared to vehicle-treated animals. Similarly, sAPPalpha-treated animals demonstrated a reduction in axonal injury within the corpus callosum at all time points, with the reduction being significant at both 3 and 7 days postinjury. Our results demonstrate that in vivo administration of sAPPalpha improves functional outcome and reduces neuronal cell loss and axonal injury following severe diffuse TBI in rats. Promotion of APP processing toward sAPPalpha may thus be a novel therapeutic strategy in the treatment of TBI.
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Affiliation(s)
- Emma Thornton
- Department of Pathology Level 3, Medical School North, The University of Adelaide South Australia, Australia 5005
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Gallyas F, Pál J, Farkas O, Dóczi T. The fate of axons subjected to traumatic ultrastructural (neurofilament) compaction: an electron-microscopic study. Acta Neuropathol 2006; 111:229-37. [PMID: 16485106 DOI: 10.1007/s00401-006-0034-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 12/07/2005] [Accepted: 12/09/2005] [Indexed: 10/25/2022]
Abstract
By means of a new head-injury apparatus, a 0.75-mm-deep depression was produced momentarily at a predetermined site of the rat calvaria. This immediately evoked ultrastructural (neurofilament) compaction in many myelinated axon segments in layers IV and V of the neocortex under the impact site. The affected axon segments run quasi-parallel to the brain surface in a diffuse distribution among normal axons. Other kinds of damage to the brain tissue were insignificant; the conditions were therefore favorable for investigation of the fate of the compacted axons. Quantitative analysis of the findings on groups of ten rats that were sacrificed either immediately after the head injury or following a 1 day or a 1 week survival period showed that around 50% of the compacted axons recovered in 1 day, and a further less than 10% did so in 1 week. Electron microscopy revealed that the non-recovering compacted axons underwent a sequence of degenerative morphological changes including homogenization, fragmentation and resorption of the fragments. However, the myelin sheaths around these degenerating axons remained apparently unchanged even in the long-surviving rats, and hardly any phagocytotic cells were encountered. On the other hand, many such myelin sheaths contained axolemma-bound, normal-looking axoplasm besides the above morphological signs of axon-degeneration. It is concluded that the non-recovering compacted axons undergo an uncommon (non-Wallerian) kind of degeneration, which is mostly reversible.
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Affiliation(s)
- Ferenc Gallyas
- Department of Neurosurgery, Faculty of Medicine, Pécs University, Rét utca 2, 7623, Pécs, Hungary.
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44
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Mázló M, Gasz B, Szigeti A, Zsombok A, Gallyas F. Debris of "dark" (compacted) neurones are removed from an otherwise undamaged environment mainly by astrocytes via blood vessels. ACTA ACUST UNITED AC 2005; 33:557-67. [PMID: 15906162 DOI: 10.1007/s11068-004-0517-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Revised: 02/04/2005] [Accepted: 02/07/2005] [Indexed: 10/25/2022]
Abstract
By means of a condenser-discharge electric shock paradigm, "dark" granule neurones were momentarily produced in a sporadic distribution among normal ones in the otherwise undamaged (non-necrotic, non-excitotoxic, non-inflammatory or non-contused) hippocampal dentate gyri of the rat brain. In the electron microscope, the ultrastructural elements of the affected neurones remained undamaged but turned markedly electron-dense and the distances between them became strikingly reduced (compaction). A proportion of such neurones recovered in 1 day while others died. During the first week of survival, the dead "dark" granule neurones retained the compacted and electron-dense ultrastructure, but underwent cytoplasmic convolution and fragmentation. The fragments were enclosed by membranes and separated from each other and from the intact neuropil by astrocytic processes containing an excess of glycogen particles. Neither proliferation of microglial cells nor infiltration of haematogenous macrophages was observed. A few fragments were taken over by resting microglial cells, while the majority was engulfed by astrocytes. The latter transported the engulfed fragments, either unchanged or digested to various degrees, to capillaries, arterioles and venules. Thereafter, the astrocyte-engulfed neuronal fragments, as well as their partly or completely digested remnants, were either transferred to phagocytotic pericytes or discharged into vascular lumina.
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Affiliation(s)
- Mária Mázló
- Central Electron-Microscopic Laboratory, Pécs University, Rét utca 2, H-7623, Pécs, Hungary
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45
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Ostrowski RP, Colohan ART, Zhang JH. Mechanisms of hyperbaric oxygen-induced neuroprotection in a rat model of subarachnoid hemorrhage. J Cereb Blood Flow Metab 2005; 25:554-71. [PMID: 15703702 DOI: 10.1038/sj.jcbfm.9600048] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Acute cerebral ischemia occurs after subarachnoid hemorrhage (SAH) because of increased intracranial pressure (ICP) and decreased cerebral perfusion pressure (CPP). The effect of hyperbaric oxygen (HBO) on physiological and clinical outcomes after SAH, as well as the expressions of hypoxia-inducible factor-1alpha (HIF-1alpha) and its target genes, such as BNIP3 and VEGF was evaluated. Eighty-five male SD rats (300 to 350 g) were randomly assigned to sham, SAH, and SAH+HBO groups. Subarachnoid hemorrhage was induced by endovascular perforation. Cortical cerebral blood flow (CBF), ICP, brain water content, brain swelling, neurologic function, and mortality were assessed. HBO (100% O2, 2.8 ATA for 2 h) was initiated at 1 h after SAH. Rats were sacrificed at 24 h to harvest tissues for Western blot or for histology. Apoptotic morphology accompanied by strong immunostaining of HIF-1alpha, VEGF, and BNIP3 were observed in the hippocampus and the cortex after SAH. Increased expressions of HIF-1alpha, VEGF, and BNIP3 were quantified by Western blot. HBO reduced the expressions of HIF-1alpha, VEGF, and BNIP3, diminished neuronal damage and improved CBF and neurologic function. HBO reduced early brain injury after SAH, probably by inhibition of HIF-1alpha and its target genes, which led to the decrease of apoptosis and preservation of the blood-brain barrier function.
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Affiliation(s)
- Robert P Ostrowski
- Department of Physiology, Loma Linda University, Loma Linda, California, USA
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Zsombok A, Tóth Z, Gallyas F. Basophilia, acidophilia and argyrophilia of “dark” (compacted) neurons during their formation, recovery or death in an otherwise undamaged environment. J Neurosci Methods 2005; 142:145-52. [PMID: 15652628 DOI: 10.1016/j.jneumeth.2004.08.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Revised: 08/11/2004] [Accepted: 08/16/2004] [Indexed: 11/15/2022]
Abstract
By means of a condenser discharge electric shock paradigm, "dark" (compacted) granule neurons were momentarily produced in the hippocampal dentate gyri of rats, which were sacrificed either immediately or following survival periods ranging from 1h to 30 days. Except for the morphological changes related to the formation, recovery or death of the "dark" neurons, the affected brain areas remained undamaged. Vibratome, frozen, cryostat and paraffin sections were stained with Mayer's hematoxylin, acid fuchsin, or Fluoro-Jade and by three silver methods widely used for the demonstration of damaged neurons; with or without previous removal of nucleic acids, partial digestion of proteins or blockade of the negatively charged side-groups of nucleic acids and proteins. The results allowed the following conclusions: (i) "Dark" neurons acquire argyrophilia and excess basophilia simultaneously with their momentary formation. (ii) Negatively charged protein molecules are responsible for these processes. (iii) From the recovering "dark" neurons, the acquired basophilia and argyrophilia disappear within a few hours post-insult. (iv) From the moribund or dead "dark" neurons, the acquired basophilia disappears in the same period of time while the acquired argyrophilia in a few days. (vi) Freshly-produced or recovering "dark" neurons are slightly acidophilic, whereas the moribund or dead ones display intense acidophilia.
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Affiliation(s)
- Andrea Zsombok
- Department of Neurosurgery, Clinical Neuroscience Research Group of the Hungarian Academy of Sciences, Section of Neuropathology, Faculty of Medicine, Pécs University, Rét utca 2, H-7623 Pécs, Hungary.
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Polgár E, Gray S, Riddell JS, Todd AJ. Lack of evidence for significant neuronal loss in laminae I-III of the spinal dorsal horn of the rat in the chronic constriction injury model. Pain 2004; 111:144-50. [PMID: 15327818 DOI: 10.1016/j.pain.2004.06.011] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Revised: 05/12/2004] [Accepted: 06/07/2004] [Indexed: 11/30/2022]
Abstract
Peripheral nerve injury leads to structural and functional changes in the spinal dorsal horn, and these are thought to be involved in the development of neuropathic pain. In the chronic constriction injury (CCI) model, abnormal 'dark' neurons and apoptotic nuclei have been observed in laminae I-III of the dorsal horn in the territory innervated by the injured sciatic nerve. These findings have been taken as evidence that there is significant neuronal death in this model, and it has been suggested that loss of inhibition resulting from death of GABAergic inhibitory interneurons contributes to the neuropathic pain. However, loss of neurons from the dorsal horn has not been directly demonstrated in neuropathic models, even though this issue is of considerable importance for our understanding of the mechanisms that underlie neuropathic pain. In this study, we have looked for evidence of neuronal death by using a stereological method (the optical disector) with NeuN-immunostaining, and examining spinal cords of naïve rats, and of rats that had undergone CCI or sham operations. All of the CCI animals showed clear signs of thermal hyperalgesia. However, the numbers of neurons in laminae I-III of the ipsilateral dorsal horn in these animals did not differ significantly from those on the contralateral side, nor from those of sham-operated or naïve animals. These results do not, therefore, support the suggestion that there is significant neuronal death in the dorsal horn in this model.
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Affiliation(s)
- E Polgár
- Spinal Cord Group, Institute of Biomedical and Life Sciences, University of Glasgow, West Medical Building, Glasgow G12 8QQ, UK.
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Gallyas F, Csordás A, Schwarcz A, Mázló M. ?Dark? (compacted) neurons may not die through the necrotic pathway. Exp Brain Res 2004; 160:473-86. [PMID: 15480602 DOI: 10.1007/s00221-004-2037-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Accepted: 06/29/2004] [Indexed: 10/26/2022]
Abstract
"Dark" neurons were produced in the cortex of the rat brain by hypoglycemic convulsions. In the somatodendritic domain of each affected neuron, the ultrastructural elements, except for disturbed mitochondria, were remarkably preserved during the acute stage, but the distances between them were reduced dramatically (ultrastructural compaction). Following a 1-min convulsion period, only a few neurons were involved and their environment appeared undamaged. In contrast, 1-h convulsions affected many neurons and caused swelling of astrocytic processes and neuronal dendrites (excitotoxic neuropil). A proportion of "dark" neurons recovered the normal structure in 2 days. The non-recovering "dark" neurons were removed from the brain cortex through two entirely different pathways. In the case of 1-h convulsions, their organelles swelled, then disintegrated and finally dispersed into the neuropil through large gaps in the plasma membrane (necrotic-like removal). Following a 1-min convulsion period, the non-recovering "dark" neurons fell apart into membrane-bound fragments that retained the compacted interior even after being engulfed by astrocytes or microglial cells (apoptotic-like removal). Consequently, in contrast to what is generally accepted, the "dark" neurons produced by 1-min hypoglycemic convulsions do not die as a consequence of necrosis. As regards the case of 1-h convulsions, it is assumed that a necrotic-like removal process is imposed, by an excitotoxic environment, on "dark" neurons that previously died through a non-necrotic pathway. Apoptotic neurons were produced in the hippocampal dentate gyrus by intraventricularly administered colchicine. After the biochemical processes had been completed and the chromatin condensation in the nucleus had reached an advanced phase, the ultrastructural elements in the somatodendritic cytoplasm of the affected cells became compacted. If present in an apparently undamaged environment such apoptotic neurons were removed from the dentate gyrus through the apoptotic sequence of morphological changes, whereas those present in an impaired environment were removed through a necrotic-like sequence of morphological changes. This suggests that the removal pathway may depend on the environment and not on the death pathway, as also assumed in the case of the "dark" neurons produced by hypoglycemic convulsions.
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Affiliation(s)
- Ferenc Gallyas
- Department of Neurosurgery, Faculty of Medicine, Pécs University, Rét utca 2, 7623 Pécs, Hungary.
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