Demyelination of the brain tissue in rats with acute CO poisoning and effects of HBO intervention

Abstract

Objective To observe changes in myelin morphology and the expression of myelin basic protein (MBP) in the brain tissue of rats through the establishment of the acute CO poisoning model,and to provide new experimental evidence for the research of the pathogenic mechanism of the delayed neuropathological sequelae (DNS) induced by acute CO poisoning.Methods Sixty male healthy SD rats were randomly divided into the control group,the intoxication day 3,7,14 and 30 groups,and the intoxication + 14-day HBO group,each consisting of 10 animals.Animals in the control group did not receive any treatment.Acute CO poisoning model was developed in the animals of the 4 intoxication groups by inhaling CO mixed air,then,the animals breathed air until consciousness recovered.Acute CO poisoning model was also developed in the animals of the intoxication + 14-day HBO group by using the same method,then the animals received 14 days of HBO treatment.Samples were taken from the animals of all the groups at different time points.Pathomorphological changes in myelin was observed with electron microscopy and Luxol fast blue staining,while the expression of MBP was detected with immunohistochemistry and Western blotting.Results Electron microscopy and Luxol fast blue staining indicated that changes in myelin began to display in the animals of the intoxication day 3 group,and typical demyelination was shown in the intoxication day 14 group.IOD of the nerve fiber decreased,when compared with that of the control group (P＜0.05).Demyelination for the animals of the intoxication + 14-day HBO group was less severe than that of the intoxication day 14 group,and the level of IOD increased ( P ＜ 0.05 ),however,myelin abnormality still existed.Immunohistochemistry demonstrated that the expression of MBP began to decrease for the animals of the intoxication day 3 group,and the expression level of MBP for the intoxication day 14 group decreased to its lowest point,and there was statistical significance in the IOD level of MBP,when compared with that of the control group ( P ＜ 0.05 ).Results of Western blotting showed that the expression of MBP for the intoxication day 3 group decreased,the MBP expression for the intoxication day 14 group decreased to its lowest (P ＜ 0.05),and the MBP expression for the intoxication + 14-day HBO group decreased,when compared with that of the intoxication day 14 group (P＜0.05).Conclusions When a comparison was made with the animals of the control group,typical demyelination was noted in the brain tissue of rats with acute CO poisoning.Through reduction of such pathological changes,HBO could relieve cerebral lesion induced by acute CO poisoning. Key words: Acute Carbon monoxide poisoning; Delayed neuropathological sequelae; Hyperbaric oxygen; Demyelination; Myelin basic protein