Effects of hyperbaric oxygen on learning and memory ability and myelin basic proteins in brain tissue after carbon monoxide poisoning

Objective To observe the effects of hyperbaric oxygen (HBO) on learning and memory ability and on the level of myelin basic protein (MBP) in the brain tissue of rats with delayed neurological sequelae (DNS) after acute carbon monoxide poisoning (COP).Methods Forty-eight male SD rats had their cognitive performance assessed with the Morris water maze.After basic training with the Morris water maze and screening,the rats were randomly divided intoanormalcontrol (NC) group (n=11),a COP group (n=17) and an HBO group (n=17).Pure CO gas was injected intraperitoneally to establish acute COP in the latter two groups.The NC group received a similar injection of air.The HBO group was given HBO therapy.The rats in each group were tested for changes in their learning and memory abilities using the Morris water maze.On the 21 st day after the treatment,paraffin tissue sections of the rats' brains were subjected to immunohistochemical (IHC) examination and Western blotting (WB) was used to detect any expression of MBP in the brain tissue.Results After 21 days,morbidity among the COP group was 64.3％,while it was 26.7％ in the HBO group,a significant difference.The average maze escape latency in the COP group was significantly longer than in the HBO group.IHC staining and Western blotting showed that MBP in the hippocampal tissue of the COP group was significantly lower than that in the HBO group.In gray scale comparisons of the rats' brain tissue,that from the NC group was significantly better than that from the COP and HBO groups,but that from the HBO group was significantly better than that from the COP group.Conclusion HBO can effectively reduce DNS after acute COP,mitigate the severity of DNS,reduce demyelination of brain tissue and thus play an important role in protecting brain cells. Key words: Hyperbaric oxygen;  Carbon monoxide poisoning;  Myelin basic protein;  Memory;  Learning