title: Transient degradation of myelin basic protein in the rat hippocampus following acute carbon monoxide poisoning.
abstract: The neurotoxicity of carbon monoxide (CO) poisoning is a significant clinical problem, but its mechanisms remain unclear. Previous studies of CO-exposed rats showed spatial memory disturbances and degradation of myelin basic protein (MBP) in the brain; however, regional localization of the degradation was not analyzed. In the present study, we histologically determined the foci of CO effects in the hippocampus. Wistar rats were exposed to CO for 60min (1000ppm for 40min+3000ppm for 20min) and returned into room air. For histological evaluation, the animals were sacrificed 90min, 1, 7 and 14 days after CO exposure and the brain tissue was analyzed with hematoxylin-eosin (HE), Nissl and Gallyas myelin staining as well as immunohistochemistry for MBP and phosphorylated or nonphosphorylated neurofilament. No histological changes were observed on HE, Nissl or Gallyas staining. In contrast, we detected MBP reduction at 90min after CO exposure in the dentate gyrus and CA3, and the recovery of MBP was observed after 14 days. The immunoreactivity of neurofilament also changed after CO exposure. Nevertheless, water maze test showed no significant effects of CO exposure on spatial memory. Our findings demonstrate that CO poisoning causes transient degradation of MBP and axonal injury in the hippocampus even though the animals showed no neurological disturbances.
authors.affiliation: Division of Environmental Medicine, National Defense Medical College Research Institute, Tokorozawa, Saitama 359-8513, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Watanabe
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Matsuo
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Satoh
authors.forename: Masanori
authors.initials: M
authors.lastname: Fujita
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Nakayama
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Nariyoshi
authors.initials: N
authors.lastname: Shinomiya
authors.forename: Shinya
authors.initials: S
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002248:Carbon Monoxide / Q000008:administration & dosage*; D002249:Carbon Monoxide Poisoning / Q000378:metabolism / Q000473:pathology*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D018782:Maze Learning / Q000187:drug effects; D004676:Myelin Basic Protein / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D004676:Myelin Basic Protein; D002248:Carbon Monoxide