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Rabow Z, Morningstar T, Showalter M, Heil H, Thongphanh K, Fan S, Chan J, Martínez-Cerdeño V, Berman R, Zagzag D, Nudler E, Fiehn O, Lechpammer M. Exposure to DMSO during infancy alters neurochemistry, social interactions, and brain morphology in long-evans rats. Brain Behav 2021; 11:e02146. [PMID: 33838015 PMCID: PMC8119844 DOI: 10.1002/brb3.2146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION Dimethyl sulfoxide (DMSO) is a widely used solvent to dissolve hydrophobic substances for clinical uses and experimental in vivo purposes. While usually regarded safe, our prior studies suggest changes to behavior following DMSO exposure. We therefore evaluated the effects of a five-day, short-term exposure to DMSO on postnatal infant rats (P6-10). METHODS DMSO was intraperitoneally injected for five days at 0.2, 2.0, and 4.0 ml/kg body mass. One cohort of animals was sacrificed 24 hr after DMSO exposure to analyze the neurometabolic changes in four brain regions (cortex, hippocampus, basal ganglia, and cerebellum) by hydrophilic interaction liquid chromatography. A second cohort of animals was used to analyze chronic alterations to behavior and pathological changes to glia and neuronal cells later in life (P21-P40). RESULTS 164 metabolites, including key regulatory molecules (retinoic acid, orotic acid, adrenic acid, and hypotaurine), were found significantly altered by DMSO exposure in at least one of the brain regions at P11 (p < .05). Behavioral tests showed significant hypoactive behavior and decreased social habits to the 2.0 and 4.0 ml DMSO/kg groups (p < .01). Significant increases in number of microglia and astrocytes at P40 were observed in the 4.0 ml DMSO/kg group (at p < .015.) CONCLUSIONS: Despite short-term exposure at low, putatively nontoxic concentrations, DMSO led to changes in behavior and social preferences, chronic alterations in glial cells, and changes in essential regulatory brain metabolites. The chronic neurological effects of DMSO exposure reported here raise concerns about its neurotoxicity and consequent safety in human medical applications and clinical trials.
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Affiliation(s)
- Zachary Rabow
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California Davis, Sacramento, CA, USA.,NIH West Coast Metabolomics Center, University of California Davis, Davis, CA, USA
| | - Taryn Morningstar
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California Davis, Sacramento, CA, USA
| | - Megan Showalter
- NIH West Coast Metabolomics Center, University of California Davis, Davis, CA, USA
| | - Hailey Heil
- NIH West Coast Metabolomics Center, University of California Davis, Davis, CA, USA
| | - Krista Thongphanh
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California Davis, Sacramento, CA, USA
| | - Sili Fan
- NIH West Coast Metabolomics Center, University of California Davis, Davis, CA, USA
| | - Joanne Chan
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California Davis, Sacramento, CA, USA
| | - Verónica Martínez-Cerdeño
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California Davis, Sacramento, CA, USA.,MIND Institute, University of California Davis, Sacramento, CA, USA.,Institute for Pediatric Regenerative Medicine and Shriners Hospital for Children of Northern California, Sacramento, CA, USA
| | - Robert Berman
- MIND Institute, University of California Davis, Sacramento, CA, USA.,Department of Neurological Surgery, University of California Davis, Sacramento, CA, USA
| | - David Zagzag
- Departments of Pathology and Neurosurgery, Division of Neuropathology, NYU Langone Medical Center, New York, NY, USA
| | - Evgeny Nudler
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY, USA.,Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Oliver Fiehn
- NIH West Coast Metabolomics Center, University of California Davis, Davis, CA, USA
| | - Mirna Lechpammer
- Department of Pathology and Laboratory Medicine, School of Medicine, University of California Davis, Sacramento, CA, USA.,MIND Institute, University of California Davis, Sacramento, CA, USA.,Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.,Pathology, Foundation Medicine, Inc., Cambridge, MA, USA
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Abstract
N-Acetyl-L-aspartate (NAA) is an amino acid that is present in the vertebrate brain. Its concentration is one of the highest of all free amino acids and, although NAA is synthesized and stored primarily in neurons, it cannot be hydrolyzed in these cells. Furthermore, neuronal NAA is dynamic and turns over more than once each day by virtue of its continuous efflux, in a regulated intercompartmental cycling via extracellular fluids, between neurons and a second compartment in oligodendrocytes. The metabolism of NAA, between its anabolic compartment in neurons and its catabolic compartment in oligodendrocytes, and its possible physiological role in the brain has been the subject of much speculation. There are two human inborn errors in metabolism of NAA. One is Canavan disease (CD), in which there is a buildup of NAA (hyperacetylaspartia) and associated spongiform leukodystrophy, caused by a lack of aspartoacylase activity. The other is a singular human case of lack of NAA (hypoacetylaspartia), where the enzyme that synthesizes NAA is apparently absent. There are two animal models currently available for studies of CD. One is a rat with a natural deletion of the catabolic enzyme, and the other a gene knockout mouse. In addition to the presence of NAA in neurons, its prominence in 1H nuclear magnetic resonance spectroscopic studies has led to its wide use in diagnostic human medicine as both an indicator of brain pathology and of disease progression in a variety of CNS diseases. In this review, various hypotheses regarding the metabolism of NAA and its possible role in the CNS are evaluated. Based on this analysis, it is concluded that although NAA may have several functions in the CNS, an important role of the NAA intercompartmental system is osmoregulatory, and in this role it may be the primary mechanism for the removal of intracellular water, against a water gradient, from myelinated neurons.
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Affiliation(s)
- Morris H Baslow
- Nathan S. Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, New York 10962, USA.
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Sonnewald U, Risan AG, Hole HB, Westergaard N, Qu H. Citrate, beneficial or deleterious in the CNS? Neurochem Res 2002; 27:155-9. [PMID: 11926269 DOI: 10.1023/a:1014823226782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cerebellar granule neurons were incubated with or without glucose (3 mM) in the presence or absence of citrate (20 mM) using normoxic and/or hypoxic incubation conditions. During 4 h of hypoglycemia and also during hypoxia plus hypoglycemia, citrate increased lactate dehydrogenase (LDH) leakage from the cells and decreased mitochondrial activity, the latter was also the case in the presence of glucose. After 24 h of hypoglycemia, however, citrate decreased LDH leakage slightly, possibly due to its metabolism in the tricarboxylic acid cycle under these conditions. It should be noted that during mild hypoxia plus hypoglycemia a reduced LDH leakage was observed when compared to hypoglycemia alone. The 4 h low oxygen period did protect the neurons also during the 20 h re-oxygenation period. The present study might indicate that incubation of brain cell cultures in an atmosphere of air (30% oxygen) and 5% CO2, which is used in most laboratories, can be toxic and that oxygen concentration should be lowered considerably to mimic conditions in the brain.
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Affiliation(s)
- Ursula Sonnewald
- Department of Clinical Neuroscience, Medical Faculty, Norwegian University of Science and Technology, Trondheim.
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Alves PM, Fonseca LL, Peixoto CC, Almeida AC, Carrondo MJ, Santos H. NMR studies on energy metabolism of immobilized primary neurons and astrocytes during hypoxia, ischemia and hypoglycemia. NMR IN BIOMEDICINE 2000; 13:438-448. [PMID: 11252029 DOI: 10.1002/nbm.665] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Changes in high-energy phosphate metabolites (ATP and phosphocreatine) were monitored, in real time, by 31P-nuclear magnetic resonance in primary cell cultures of neurons and astrocytes during periods of hypoxia, ischemia and hypoglycemia, and also during the recovery periods following the re-establishment of standard conditions. Cells were immobilized in basement membrane gel threads and perfused with oxygen-depleted medium (oxygen concentration below 30 microM), to create hypoxic conditions, or with aerobic medium (oxygen concentration approximately 460 microM) containing different concentrations of glucose (hypoglycemia). Ischemic conditions were imposed by stopping perfusion for different periods of time (15 min to 2 h). The experimental set-up enabled the acquisition of 31P-spectra with high signal-to-noise ratio within 10-20 min for both cell types. The effect of hypoxia on glucose metabolism was assessed by 13C-NMR using [1-13C]glucose as substrate. The levels of ATP and PCr in astrocytes were unaffected during hypoxia (up to 2 h), but decreased notably under ischemia. In neurons, hypoxic periods caused a sharp drop of the ATP and PCr levels, and considerable damage to the capacity of neurons to replenish the ATP and PCr pools upon returning to normoxic conditions. However, neurons were remarkably less sensitive to ischemic conditions, the ATP and PCr pools being restored quickly, even after 2 h under challenging conditions. The data show that neurons were more resistant to ischemia than astrocytes, and suggest that the capacity to sustain the pools of ATP and PCr was part of the neuronal protective strategy.
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Affiliation(s)
- P M Alves
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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Akiho H, Iwai A, Tsukamoto S, Koshiya K, Yamaguchi T. Neuroprotective effect of YM-39558 in focal cerebral ischemia in cats. Neuropharmacology 1998; 37:159-68. [PMID: 9680240 DOI: 10.1016/s0028-3908(98)00008-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We studied the effect of YM-39558, orotic acid ethylester, in a focal cerebral ischemia model in anesthetized cats. YM-39558 has good permeability across the blood brain barrier, and in the brain is hydrolyzed to orotic acid, the main active substance. Cats were subjected to permanent occlusion of the middle cerebral artery (MCA) for 6 h, then killed and examined histologically. Treatment with YM-39558 (intravenous infusion of 11.8 mg (10 mg as orotic acid)/6 ml per kg per h) starting 15 min after MCA occlusion markedly reduced the volume of ischemic damage (from 2450 +/- 82 mm3 of the cerebral hemisphere in the saline-treated cats to 1644 +/- 123 mm3 in the YM-39558-treated cats, P < 0.01). In contrast, YM-39558 (2.26 and 1.18 mg/0.8 ml per kg per h) showed no significant protective effect on ischemic damage. No significant differences were observed between saline- and YM-39558-treated cats concerning physiological variables including brain temperature. This evidence for the neuroprotective efficacy of YM-39558 in gyrencephalic species suggests its therapeutic potential in the treatment of stroke in humans.
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Affiliation(s)
- H Akiho
- Neuroscience Research, Pharmacology Laboratories, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical, Tsukuba, Ibaraki, Japan.
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Akiho H, Iwai A, Katoh-Sudoh M, Tsukamoto S, Koshiya K, Yamaguchi T. Neuroprotective effect of YM-39558, orotic acid ethylester, in gerbil forebrain ischemia. JAPANESE JOURNAL OF PHARMACOLOGY 1998; 76:441-4. [PMID: 9623724 DOI: 10.1254/jjp.76.441] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We studied the effects of orotic acid and YM-39558 (2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid ethyl ester), orotic acid ethylester, on delayed neuronal death of hippocampal CA1 neurons induced by transient forebrain ischemia. Our data indicated that YM-39558 had high permeability across the blood brain barrier and was hydrolyzed to orotic acid, the active substance, in the brain. The neuronal damage was reduced significantly in animals intraperitoneally treated with YM-39558 (100 mg/kg x 3) after ischemia, but not with orotic acid in the same way. The results also suggested that the maintenance of a few ten micromolar orotic acid in cerebrospinal fluid were needed for its neuroprotective effects.
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Affiliation(s)
- H Akiho
- Pharmacology Laboratories, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan
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