Ultrastructure of Purkinje cell perikarya and their dendritic processes in the rat cerebellar cortex in experimental encephalopathy induced by chronic application of valproate

Investigating the role of Purkinje fibers and synaptic connectivity in balance regulation through comprehensive ultrastructural and immunohistochemical analysis of the donkey's (Equus asinus) cerebellum

The donkey's extraordinary capacity to endure substantial loads over long distances while maintaining equilibrium suggests a distinctive cerebellar architecture specialized in balance regulation. Consequently, our study aims to investigate the intricate histophysiology of the donkey's cerebellum using advanced ultrastructural and immunohistochemical methodologies to comprehend the mechanisms that govern this exceptional ability. This study represents the pioneering investigation to comprehensively describe the ultrastructure and immunohistochemistry within the donkey cerebellum. Five adult donkeys' cerebella were utilized for the study, employing stains such as hematoxylin, eosin, and toluidine blue to facilitate a comprehensive histological examination. For immunohistochemical investigation, synaptophysin (SP), calretinin, and glial fibrillary acidic protein were used and evaluated by the Image J software. Furthermore, a double immunofluorescence staining of SP and neuron-specific enolase (NSE) was performed to highlight the co-localization of these markers and explore their potential contribution to synaptic function within the donkey cerebellum. This investigation aims to understand their possible roles in regulating neuronal activity and synaptic connectivity. We observed co-expression of SP and NSE in the donkey cerebellum, which emphasizes the crucial role of efficient energy utilization for motor coordination and balance, highlighting the interdependence of synaptic function and energy metabolism. The Purkinje cells were situated in the intermediate zone of the cerebellum cortex, known as the Purkinje cell layer. Characteristically, the Purkinje cell's bodies exhibited a distinct pear-like shape. The cross-section area of the Purkinje cells was 107.7 ± 0.2 µm2 , and the Purkinje cell nucleus was 95.7 ± 0.1 µm2 . The length and diameter of the Purkinje cells were 36.4 × 23.4 µm. By scanning electron microscopy, the body of the Purkinje cell looked like a triangular or oval with a meandrous outer surface. The dendrites appeared to have small spines. The Purkinje cells' cytoplasm was rich with mitochondria, rough endoplasmic reticulum, ribosomes, Golgi apparatus, multivesicular bodies, and lysosomes. Purkinje cell dendrites were discovered in the molecular layer, resembling trees. This study sheds light on the anatomical and cellular characteristics underlying the donkey's exceptional balance-maintaining abilities.

Ameliorative effect of vitamin E and selenium against bisphenol A-induced toxicity in spinal cord and submandibular salivary glands of adult male albino rats

Bisphenol A (BPA) used in plastic industry. This study evaluate ameliorative effect of vitamin E and selenium in combating BPA toxicity in spinal cord (SC) and submandibular glands (SMGs). Thirty rats divided into three groups [Group I, controls; Group II, BPA orally (25 mg/kg) three times a week, 60 days; Group III, BPA (25 mg/kg) plus vitamin E and selenium in water (1 ml/L/day)]. By histopathological, immunohistochemical, and biochemical investigations. Bisphenol A group showed degenerative alterations. SC gray matter showed pyknotic nuclei and white matter revealed neuropil degeneration. Myelinated fibers showed dispersed myelin. SMGs, exhibited vacuolated cytoplasm in acinar cells. Intense glial fibrillary acidic protein in SC and strong proliferating cell nuclear antigen in acinar and ductal cell nuclei of SMGs. Malondialdehyde elevated in SC and catalase decreased in SMG. Group III, SC and SMG revealed partial recovery. Vitamin E and selenium displayed protective effects against BPA toxicity in SC and SMGs.

Electron microscopic study on the effect of chronic fluoxetine treatment on pituitary gland and the possible therapeutic effect of adipose-derived mesenchymal stem cells in adult male albino rats

BACKGROUND

Adipose-derived mesenchymal stem cells (ADSCs) have therapeutic potential for the treatment of a variety of disorders due to their self-renewal and multipotential differentiation capabilities.

AIM OF THE WORK

This study was planned to demonstrate the electron microscopic structure of the pituitary gland after chronic fluoxetine treatment and the possible therapeutic effect of ADSCs.

MATERIALS AND METHODS

Thirty healthy male adult albino rats were classified into Control group (Group I). Fluoxetine treated (Group II) received 24 mg/kg/day of fluoxetine dissolved in 1.0 mL of tap water once a day. Fluoxetine group treated with ADSCs (Group III) received fluoxetine as group (II) for 30 days and then was injected once by ADSCs at a dose of 1 × 106 cells/rat in the tail vein suspended in 0.5 ml of phosphate-buffered saline (PBS). Recovery group (Group IV) received fluoxetine for 30 days and then received no treatment till the end of the experiment.

RESULTS

The ultrastructural observations of the fluoxetine-treated group revealed major histological changes in both the pars distalis and nervosa. Pars distalis revealed cells with different shapes, sizes, nuclei, and variable profiles of the cytoplasm. Pars nervosa, on the other hand, revealed pituicytes with electron-lucent cytoplasm and small apoptotic nuclei. Administration of ADSCs greatly improved the microscopic appearance of cells, while the recovery group showed similar histological changes as the fluoxetine group.

CONCLUSION

Fluoxetine caused various deleterious changes in the pituitary gland of albino rats, as evidenced by electron microscopy. These changes were almost corrected by the ADSCs treatment.    .

Cerebellar and Striatal Implications in Autism Spectrum Disorders: From Clinical Observations to Animal Models

Autism spectrum disorders (ASD) are complex conditions that stem from a combination of genetic, epigenetic and environmental influences during early pre- and postnatal childhood. The review focuses on the cerebellum and the striatum, two structures involved in motor, sensory, cognitive and social functions altered in ASD. We summarize clinical and fundamental studies highlighting the importance of these two structures in ASD. We further discuss the relation between cellular and molecular alterations with the observed behavior at the social, cognitive, motor and gait levels. Functional correlates regarding neuronal activity are also detailed wherever possible, and sexual dimorphism is explored pointing to the need to apprehend ASD in both sexes, as findings can be dramatically different at both quantitative and qualitative levels. The review focuses also on a set of three recent papers from our laboratory where we explored motor and gait function in various genetic and environmental ASD animal models. We report that motor and gait behaviors can constitute an early and quantitative window to the disease, as they often correlate with the severity of social impairments and loss of cerebellar Purkinje cells. The review ends with suggestions as to the main obstacles that need to be surpassed before an appropriate management of the disease can be proposed.

Impact of copper oxide nanoparticles on the cerebral cortex of adult male albino rats and the potential protective role of crocin

The use of copper oxide nanoparticles (CUONPs) on a large-scale application is a reason for many health problems and morbidities involving most body tissues, particularly those of the nervous system. Crocin is the chemical ingredient primarily responsible for the color of saffron. It has different pharmacological effects, such as antioxidant, anticancer, and memory-improving activities. This study was conducted to elaborate the effects of CUONP exposureon the cerebellar cortical tissues of rats and explore the potential protecting role of crocin through biochemical, light microscopic, and ultrastructural examinations. Twenty four adult male albino rats were randomly divided into four equal groups: Group I (negative control); Group II (crocin-treated group; 30mg/kg body weight (BW) intraperitoneal (IP) crocin daily); Group III (CUONP-treatedgroup; 0.5-mg/kg BW IP CUONP daily); and Group IV (CUONP/crocin-treated group). After 14 days of the experiment, venous blood samples were collected to determine red blood cell (RBC), white blood cell (WBC), and hemoglobin (Hb) levels. Besides, serum malondialdehyde (MDA), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) were measured. Cerebellar tissue samples were examined under light and electron microscopy along with a histomorphological analysis. CUONPs induced oxidative/antioxidative imbalance as evidenced by a significant increase in serum MDA levels and decreased GPx and TAC activities. CUONPs caused a significant decrease in RBC and Hb levels and an increase in WBC count. Histopathological alterations in the cerebellar cortex were observed. The administration of crocin showed some protection against the toxic effects of CUONPs. Crocin is suggested to have a mitigating role on oxidative stress and structure alterations in the cerebellar tissues induced by CUONPs.

The Possible Neuroprotective Effect of Silymarin against Aluminum Chloride-Prompted Alzheimer's-Like Disease in Rats

Alzheimer's disease (AD) is a worldwide rapidly growing neurodegenerative disease. Here, we elucidated the neuroprotective effects of silymarin (SM) on the hippocampal tissues of aluminum chloride (AlCl3)-induced Alzheimer-like disease in rats using biochemical, histological, and ultrastructural approaches. Forty rats were divided into control, SM, AlCl3, and AlCl3 + SM groups. Biochemically, AlCl3 administration resulted in marked elevation in levels of lipid peroxidation (LPO) and nitric oxide (NO) and decrease in levels of reduced glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). Moreover, AlCl3 significantly increased tumor necrosis factor-α (TNF-α), interleukin-1beta (IL-1β), and acetylcholinesterase (AChE) activities. Furthermore, myriad histological and ultrastructural alterations were recorded in the hippocampal tissues of AlCl3-treated rats represented as marked degenerative changes of pyramidal neurons, astrocytes, and oligodendrocytes. Additionally, some myelinated nerve fibers exhibited irregular arrangement of their myelin coats, while the others revealed focal degranulation of their myelin sheaths. Severe defects in the blood-brain barrier (BBB) were also recorded. However, co-administration of SM with AlCl3 reversed most of the biochemical, histological, and ultrastructural changes triggered by AlCl3 in rats. The results of the current study indicate that SM can potentially mend most of the previously evoked neuronal damage in the hippocampal tissues of AlCl3-kindled rats.

Cadmium Chloride Induces Memory Deficits and Hippocampal Damage by Activating the JNK/p66Shc/NADPH Oxidase Axis

This study investigated whether the mechanism underlying the neurotoxic effects of cadmium chloride (CdCl₂) in rats involves p⁶⁶Shc. This study comprised an initial in vivo experiment followed by an in vitro experiment. For the in vivo experiment, male rats were orally administered saline (vehicle) or CdCl₂ (0.05 mg/kg) for 30 days. Thereafter, spatial and retention memory of rats were tested and their hippocampi were used for biochemical and molecular analyses. For the in vitro experiment, control or p⁶⁶Shc-deficient hippocampal cells were treated with CdCl₂ (25 µM) in the presence or absence of SP600125, a c-Jun N-terminal kinase (JNK) inhibitor. Cadmium chloride impaired the spatial learning and retention memory of rats; depleted levels of glutathione and manganese superoxide dismutase; increased reactive oxygen species (ROS), tumor necrosis factor α, and interleukin 6; and induced nuclear factor kappa B activation. Cadmium chloride also decreased the number of pyramidal cells in the CA1 region and induced severe damage to the mitochondria and endoplasmic reticulum of cells in the hippocampi of rats. Moreover, CdCl₂ increased the total unphosphorylated p66Shc, phosphorylated (Ser³⁶) p⁶⁶Shc, phosphorylated JNK, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, cytochrome c, and cleaved caspase-3. A dose-response increase in cell death, ROS, DNA damage, p⁶⁶Shc, and NADPH oxidase was also observed in cultured hippocampal cells treated with CdCl₂. Of note, all of these biochemical changes were attenuated by silencing p⁶⁶Shc or inhibiting JNK with SP600125. In conclusion, CdCl₂ induces hippocampal ROS generation and apoptosis by promoting the JNK-mediated activation of p⁶⁶Shc.

Role of aqueous extract of saffron in ameliorating effect of sofosbuvir on the cerebellar cortex in rat

Sofosbuvir is a promising antiviral drug against chronic hepatitis C virus. Although it is characterized by its high efficacy, its adverse effects on nervous tissue are still unclear. Saffron is known for its neuroprotective property. This is a biochemical, histological and immunohistochemical study of the effect of sofosbuvir on the cerebellar cortex of rat and the possible ameliorating role of saffron's aqueous extract. Twenty-four adult male Wistar albino rats were equally divided into four groups; control, saffron extract-treated, sofosbuvir-treated (41.1 mg/kg/day for 6 weeks) and group concomitantly treated with saffron extract and sofosbuvir. Sofosbuvir-treated group recorded a significant increase in cerebellar malondialdehyde level coupling with a significant decrease in tissue glutathione and superoxide dismutase. Light microscopy revealed reduced number of Purkinje cells. The granular layer depicted many granular cells and Bergmann astrocytes with nuclear and cytoplasmic alterations. Electron microscopy revealed disorganized molecular layer with disarranged myelinated axons and disrupted mitochondria. Few shrunken Purkinje cells showed electron-dense cytoplasm and rarefied nuclei, indistinct nuclear envelope and dilated perinuclear space, areas of vacuolated cytoplasm, fragmented rough endoplasmic reticulum and few dark mitochondria. Some axons with tiny mitochondria were detected. A significant upregulation in immunohistochemical expression of GFAP-positive astrocytes was recorded. Concomitant administration of saffron extract significantly improved all studied parameters. Saffron extract is beneficial in ameliorating sofosbuvir-induced cerebellar morphological changes mainly through its antioxidant and neuroprotective properties.

The effects of chard on brain damage in valproic acid-induced toxicity

Valproic acid (VPA; 2-propyl valeric acid) is a potent drug widely used in treating anxiety disorders, migraine as well as epileptic diseases. In the ongoing study chard protective effect was investigated, on the damaged VPA rat brain. Sprague Dawley rats (females) were grouped as follows: control, VPA (500 mg kg-1  day-1 VPA intraperitoneal), chard (100 mg/kg day chard extract by gavage), VPA + chard (500 mg kg-1  day-1 VPA + 100 mg kg-1  day-1 chard extract). Aqueous chard leaves extract was given 1 hr before apply VPA for a period of 7 days. Lipid peroxidation, advanced oxidation protein products and protein carbonyl content, and superoxide dismutase, glutathione peroxidase, glutathione-S-transferase, and glutathione reductase activities increased in the VPA group. Reduced glutathione levels, paraoxanase, and acetylcholinesterase activities were significantly diminished in the VPA animals. Chard extract application curatively reverted the studied biochemical parameters. The results obtained, it has been found the chard has a protective and antioxidant effect on brain damage induced by VPA. PRACTICAL APPLICATIONS: Valproic acid is a comparably safe pharmaceutical agent, but it can cause severe adverse effects on biological metabolism when it is used in high amount. There are not many studies declared that VPA stimulate the generation of ROS, which is liable for the life-threatening adverse effects of VPA therapy including hepatotoxicity neurotoxicity and teratogenicity. Chard is a plant which has antimicrobial, antibacterial, antiinflammatory, antioxidant, antitumor, antiacetylcholinesterase activities, and hepatoprotective effects. In the current study we examined the protection of the VPA damaged rat brain by chard.

The possible neuroprotective role of grape seed extract on the histopathological changes of the cerebellar cortex of rats prenatally exposed to Valproic Acid: animal model of autism

Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental disease characterized by defect in verbal and nonverbal communications. As, the cerebellum has the greatest number of neurons and synapses in the central nervous system so, the cerebellum has emerged as one of the target brain areas affected in autism. The aim of this work was to study the biochemical, immunohistochemical and ultrastructural characteristics of autism and the possible neuroprotective role of grape seed extract. In this study 28 male pups were divided into Control groups; Group I (saline), Group II (GSE 400 mg/kg), Group III (VPA 500 mg/kg) and Group IV (VPA and GSE). Cerebellar hemispheres were dissected out and prepared to determine the oxidative stress markers, histological, immunohistochemical and morphometric study were done. A significant elevation in oxidative stress markers in off spring of VPA treated rats in comparison to control group was detected. A significant decrease in the Purkinje cell count and nuclear size were observed. Numerous shrunken cells with hyperchromatic nuclei and ultrastructural degeneration of cytoplasmic organelles were detected. A significant rise in the area percentage of GFAP-positive immune stained cells in comparison to that of the control groups was seen. Strikingly, GSE revealed significant improvement in the oxidative stress markers and then the histological and morphometric picture of the cerebellum. GSE has neuroprotective effect on the cerebellum of VPA treated rats through its potent antioxidant effect.

Effect of prenatal tramadol on postnatal cerebellar development: Role of oxidative stress

BACKGROUND AND AIM

The adverse neurological effects of tramadol have recently raised attention. The literature pertaining to studying postnatal cerebellar changes induced by prenatal tramadol is very scanty, thus the current study has been designed to improve understanding of the cerebellar oxidative stress-related alterations associated with tramadol administration during pregnancy in this critical period of neuronal differentiation and synaptic development, thereby highlighting the importance of controlling prenatal prescription of opioids and optimizing care for opioid-dependent pregnant women and their infants.

MATERIAL AND METHODS

Twenty pregnant female rats of Sprague Dawley strains were used in the study. Their offspring were divided into two groups: group I (control group) offspring of mothers given saline; group II offspring of mothers given tramadol from the 10th day (D10) of gestation till D21. The pups were sacrificed on the 7^th, 14^th and 21^st postnatal days. Cerebellar specimens were processed for histomorphometric, immunohistochemical and electron microscopic assessment and were evaluated for various oxidative stress parameters.

RESULTS

Tramadol administration during pregnancy caused profound structural abnormalities on the post-natal cerebellar cortex and was associated with oxidative stress evidenced by elevation of lipid peroxidation products and inhibition of antioxidant enzyme activities.

Familial Cortical Myoclonic Tremor and Epilepsy, an Enigmatic Disorder: From Phenotypes to Pathophysiology and Genetics. A Systematic Review

Background

Autosomal dominant familial cortical myoclonic tremor and epilepsy (FCMTE) is characterized by distal tremulous myoclonus, generalized seizures, and signs of cortical reflex myoclonus. FCMTE has been described in over 100 pedigrees worldwide, under several different names and acronyms. Pathological changes have been located in the cerebellum. This systematic review discusses the clinical spectrum, treatment, pathophysiology, and genetic findings.

Methods

We carried out a PubMed search, using a combination of the following search terms: cortical tremor, myoclonus, epilepsy, benign course, adult onset, familial, and autosomal dominant; this resulted in a total of 77 studies (761 patients; 126 pedigrees) fulfilling the inclusion and exclusion criteria.

Results

Phenotypic differences across pedigrees exist, possibly related to underlying genetic differences. A "benign" phenotype has been described in several Japanese families and pedigrees linked to 8q (FCMTE1). French patients (5p linkage; FCMTE3) exhibit more severe progression, and in Japanese/Chinese pedigrees (with unknown linkage) anticipation has been suggested. Preferred treatment is with valproate (mind teratogenicity), levetiracetam, and/or clonazepam. Several genes have been identified, which differ in potential pathogenicity.

Discussion

Based on the core features (above), the syndrome can be considered a distinct clinical entity. Clinical features may also include proximal myoclonus and mild progression with aging. Valproate or levetiracetam, with or without clonazepam, reduces symptoms. FCMTE is a heterogeneous disorder, and likely to include a variety of different conditions with mutations of different genes. Distinct phenotypic traits might reflect different genetic mutations. Genes involved in Purkinje cell outgrowth or those encoding for ion channels or neurotransmitters seem good candidate genes.

Sub-Lethal Dose of Shiga Toxin 2 from Enterohemorrhagic Escherichia coli Affects Balance and Cerebellar Cytoarchitecture

Shiga toxin producing Escherichia coli may damage the central nervous system before or concomitantly to manifested hemolytic–uremic syndrome symptoms. The cerebellum is frequently damaged during this syndrome, however, the deleterious effects of Shiga toxin 2 has never been integrally reported by ultrastructural, physiological and behavioral means. The aim of this study was to determine the cerebellar compromise after intravenous administration of a sub-lethal dose of Shiga toxin 2 by measuring the cerebellar blood–brain barrier permeability, behavioral task of cerebellar functionality (inclined plane test), and ultrastructural analysis (transmission electron microscope). Intravenous administration of vehicle (control group), sub-lethal dose of 0.5 and 1 ηg of Stx2 per mouse were tested for behavioral and ultrastructural studies. A set of three independent experiments were performed for each study (n = 6). Blood–brain barrier resulted damaged and consequently its permeability was significantly increased. Lower scores obtained in the inclined plane task denoted poor cerebellar functionality in comparison to their controls. The most significant lower score was obtained after 5 days of 1 ηg of toxin administration. Transmission electron microscope micrographs from the Stx2-treated groups showed neurons with a progressive neurodegenerative condition in a dose dependent manner. As sub-lethal intravenous Shiga toxin 2 altered the blood brain barrier permeability in the cerebellum the toxin penetrated the cerebellar parenchyma and produced cell damaged with significant functional implications in the test balance.

Histological Study on the Protective Role of Ascorbic Acid on Cadmium Induced Cerebral Cortical Neurotoxicity in Adult Male Albino Rats

Cadmium (Cd) toxicity represents a worldwide problem in environmental contamination and a common cause of occupational and non-occupational neurological diseases. So, this study aimed to evaluate the histological changes induced by Cd on the cerebral cortex of adult rats and evaluating the possible ameliorating role of ascorbic acid (AA). Twenty adult male rats were divided into; control group, AA group (each rat was received a daily oral dose of 200 mg AA/kg body weight (b.w) and Cd group (each rat was received 5 mg Cd/kg b.w orally) and protective group (each rat was given AA concomitantly with Cd at the same dose, route and period of administration of the previous groups. After two months the cerebral cortexes were processed for histological examination. The cerebral cortex of Cd treated animals exhibited severe degenerative changes especially in pyramidal and granule cells. Structural changes in these cells were in the form of dilated rER and Golgi complex, swollen mitochondria and marginated nuclear chromatin. Myelinated nerve fibers displayed myelination disruption and irregular neurofilaments. The neuropil appeared vacuolated with accumulation of neuroglial cells. On the other hand, these changes were ameliorated in rats which received AA concomitantly with Cd. So, it could be concluded that AA can ameliorate the histological changes induced by Cd and this direct the attention to the antioxidants as protective measures for the neurotoxicity.

Neurotoxicological effects of nicotine on the embryonic development of cerebellar cortex of chick embryo during various stages of incubation

Long-acting nicotine is known to exert pathological effects on almost all tissues including the cerebellar cortex. The present work was designed to elucidate the effect of nicotine on the development of cerebellar cortex of chick embryo during incubation period. The fertilized eggs of hen (Gallus gallus domesticus) were injected into the air space by a single dose of long acting nicotine (1.6 mg/kg/egg) at the 4th day of incubation. The embryos were taken out of the eggs on days 8, 12 and 16 of incubation. The cerebellum of the control and treated embryos at above ages were processed for histopathological examination. The TEM were examined at 16th day of incubation. The results of the present study revealed that, exposure to long-acting nicotine markedly influence the histogenesis of cerebellar cortex of chick embryo during the incubation period. At 8th day of incubation, nicotine delayed the differentiation of the cerebellar analge; especially the external granular layer (EGL) and inner cortical layer (ICL). Furthermore, at 12th day of incubation, the cerebellar foliation was irregular and the Purkinje cells not recognized. By 16th day of incubation, the cerebellar foliations were irregular with interrupted cerebellar cortex and irregular arrangement of Purkinje cells. Immunohistochemical analysis for antibody P53 protein revealed that the cerebellar cortex in all stages of nicotine treated groups possessed a moderate to weak reaction for P53 protein however; this reaction was markedly stronger in the cerebellar cortex of control groups. Moreover, the flow cytometric analysis confirmed that the percentage of apoptosis in control group was significantly higher compared with that of nicotine treated group. At the TEM level, the cerebellar Purkinje cells of 16th day of treated groups showed multiple subcellular alterations in compared with those of the corresponding control group. Such changes represented by appearing of vacuolated mitochondria, cisternal fragmentation of RER, irregular grooves of Golgi tubules. Also, multiple cytoplasmic vacuoles and aggregation of Nissl granules were recorded around pyknotic nucleus.

Time course of SERCA 2b and calreticulin expression in Purkinje neurons of ethanol-fed rats with behavioral correlates

Chronic ethanol consumption for 40 weeks in adult rats results in dilation of the extensive smooth endoplasmic reticulum (SER), a major component of the calcium homeostatic system within Purkinje neuron (PN) dendrites.

AIMS

The aim of the present study was to determine whether chronic ethanol consumption results in alterations of the sarco/endoplasmic reticulum Ca(2+) ATPase pump (SERCA) on the SER membrane of PN dendrites. The density of calreticulin, a calcium chaperone, was also investigated in the PN along with balancing ability.

METHODS

Ninety 8-month-old rats were exposed to rat chow, the AIN-93 M liquid control or ethanol diets (30/diet) for a duration of 10, 20 or 40 weeks (30/duration). Age changes relative to the rat chow controls were assessed with 3-month-old control rats (n = 10). Balance was assessed prior to euthanasia. Quantitative immunocytochemistry was used to determine the density of SERCA 2b + dendrites and calreticulin + PN soma and nuclei. Molecular layer volumes were also determined.

RESULTS

Following 40 weeks of ethanol treatment, there were ethanol-induced decreases in SERCA 2b densities within the dendritic arbor and decreased balancing ability on the more difficult round rod balance test. There were no ethanol-induced changes in calreticulin densities.

CONCLUSION

It can be concluded that ethanol-induced decreases in the SERCA pump accompany SER dilation and contribute to previously reported ethanol-induced dendritic regression in PN. Ethanol-induced changes in balance also occurred. Chronic ethanol consumption does not alter calreticulin expression in PN.

Hyperconnectivity of local neocortical microcircuitry induced by prenatal exposure to valproic acid

Exposure to valproic acid (VPA) during embryogenesis can cause several teratogenic effects, including developmental delays and in particular autism in humans if exposure occurs during the third week of gestation. We examined the postnatal effects of embryonic exposure to VPA on microcircuit properties of juvenile rat neocortex using in vitro electrophysiology. We found that a single prenatal injection of VPA on embryonic day 11.5 causes a significant enhancement of the local recurrent connectivity formed by neocortical pyramidal neurons. The study of the biophysical properties of these connections revealed weaker excitatory synaptic responses. A marked decrease of the intrinsic excitability of pyramidal neurons was also observed. Furthermore, we demonstrate a diminished number of putative synaptic contacts in connection between layer 5 pyramidal neurons. Local hyperconnectivity may render cortical modules more sensitive to stimulation and once activated, more autonomous, isolated, and more difficult to command. This could underlie some of the core symptoms observed in humans prenatally exposed to valproic acid.

A new neurobehavioral model of autism in mice: pre- and postnatal exposure to sodium valproate

Autism symptoms, including impairments in language development, social interactions, and motor skills, have been difficult to model in rodents. Since children exposed in utero to sodium valproate (VPA) demonstrate behavioral and neuroanatomical abnormalities similar to those seen in autism, the neurodevelopmental effects of this antiepileptic agent were examined in mice following its pre- or postnatal administration. Exposed pups were evaluated in a battery of neurodevelopmental procedures designed to assess VPA-induced retardation (wherein a behavior fails to mature on schedule), regression (wherein a behavior does mature on time but then deteriorates), or intrusions (wherein normal behaviors are overshadowed by stereotypic or self-injurious behaviors). The resulting observations were interpreted in the context of this new strategy to model autism.

Valproate-induced hyperammonemic encephalopathy

Valproate-induced hyperammonemic encephalopathy (VHE) is an unusual complication characterized by a decreasing level of consciousness, focal neurological deficits, cognitive slowing, vomiting, drowsiness, and lethargy. We have thoroughly reviewed the predisposing factors and their screening, the biochemical and physiopathological mechanisms involved, the different treatments described, and those that are being investigated. Etiopathogenesis is not completely understood, although hyperammonemia has been postulated as the main cause of the clinical syndrome. The increase in serum ammonium level is due to several mechanisms, the most important one appearing to be the inhibition of carbamoylphosphate synthetase-I, the enzyme that begins the urea cycle. Polytherapy with several drugs, such as phenobarbital and topiramate, seems to contribute to hyperammonemia. Hyperammonemia leads to an increase in the glutamine level in the brain, which produces astrocyte swelling and cerebral edema. There are several studies that suggest that treatment with supplements of carnitine can lead to an early favorable clinical response due to the probable carnitine deficiency induced by a valproate (VPA) treatment. Development of the progressive confusional syndrome, associated with an increase in seizure frequency after VPA treatment onset, obliges us to rule out VHE by screening for blood ammonium levels and the existence of urea cycle enzyme deficiency, such as ornithine carbamoyltransferase deficiency. Electroencephalography (EEG) is characterized by signs of severe encephalopathy with continuous generalized slowing, a predominance of theta and delta activity, occasional bursts of frontal intermittent rhythmic delta activity, and triphasic waves. These EEG findings, as well as clinical manifestations and hyperammonemia, tend to normalize after VPA withdrawal.

A transmission electron microscopic study of microglia/macrophages in the hippocampal cortex and neocortex following chronic exposure to valproate

In chronic administration of sodium valproate to rats, significant disorders of structural integrity of the hippocampal gyrus and the neocortex of the temporal lobe, observed in the last two stages of the experiment (after 9 and 12 months), coexisted with increased number of microglial cells and, especially after 12 months, with intense phagocytic activity within these cells. At the ultrastructural level, phagocyte microglial cells were hypertrophied with several broadened processes. Their cytoplasm contained rich lysosomal apparatus, numerous lipofuscin-like structures, lipid droplets and multilaminated bodies. The nuclei of these cells were characteristic oval or round and sometimes triangle in shape with dense and highly clumped heterochromatin, distinctly accumulated under nuclear envelope, and sparse euchromatin. Microglia/macrophages were frequently present in a close vicinity of changed neuronal somata and also close to the altered elements of the neuropil pyramidal layer of the cortex. Microglial response may, together with abnormalities in neurones, astroglia and blood-brain barrier, play a significant role in the development of experimental valproate encephalopathy.

Valproic acid blood genomic expression patterns in children with epilepsy - a pilot study

OBJECTIVE

Valproic acid (VPA) is a commonly used anticonvulsant with multiple systemic effects. The purpose of this pilot study is to examine the blood genomic expression pattern associated with VPA therapy in general and secondly VPA efficacy in children with epilepsy.

MATERIALS AND METHODS

Using oligonucleotide microarrays, gene expression in whole blood was assessed in pediatric epilepsy patients following treatment with VPA compared with children with epilepsy prior to initiation of anticonvulsant therapy (drug free patients).

RESULTS

The expression of 461 genes was altered in VPA patients (n = 11) compared with drug free patients (n = 7), among which a significant number of serine threonine kinases were down-regulated. Expression patterns in children seizure free on VPA therapy (n = 8) demonstrated 434 up-regulated genes, many in mitochondria, compared with VPA children with continuing seizures (n = 3) and drug free seizure patients (n = 7).

CONCLUSION

VPA therapy is associated with two significant and unique blood gene expression patterns: chronic VPA monotherapy in general and a separate blood genomic profile correlated with seizure freedom. These expression patterns provide new insight into previously undetected mechanisms of VPA anticonvulsant activity.

Ultrastructure of astrocytes in the cortex of the hippocampal gyrus and in the neocortex of the temporal lobe in experimental valproate encephalopathy and after valproate withdrawal

The aim of the study was to analyse the astrocyte ultrastructure within the hippocampal gyre cortex and neocortex of the temporal lobe in valproate encephalopathy induced by chronic administration of an anti-epileptic drug - sodium valproate (VPA) to rats for 1, 3, 6, 9 and 12 months, once daily intragastrically, in a dose of 200 mg/kg b.w. and after its withdrawal for 1 and 3 months. Prolonged application of VPA caused damage to protoplasmic astrocytes of the cortex regions examined, mainly in the pyramidal layer, which intensified in the later stages of the experiment, especially after 9 and 12 months. Ultrastructural alterations in astroglia during this experiment did not differ significantly between the hippocampal cortex and neocortex. The most pronounced astroglial abnormalities, concerning about 2/3 of protoplasmic astrocytes after 9 and 12 months, were characterized by considerable swelling of cells, with the presence of empty vacuolar structures in the cytoplasm, a substantial decrease in the number of gliofilaments or even their complete loss, which indicated fibrillopoietic failure of the cell, and the appearance of astrocytes showing phagocytic activity. The astrocytic changes coexisted with distinct damage to neurones and structural elements of the blood-brain barrier. One month after termination of chronic exposure to the drug, the abnormalities did not subside, whereas after 3 months features of distinct normalization could be observed in a considerable number, more than a half, of astrocytes. In valproate encephalopathy, apart from any direct effect of VPA and/or its metabolites on astrocytes, the main cause of the protoplasmic astroglial damage in the cortex of the CNS structures examined could be associated with changes in microcirculation in the cortex (vasogenic factor), leading to its ischaemia.