Effects of subacute high altitude hypoxia on neuronal apoptosis in hippocampal and expression of caspase-3 in hippocampus CA1 subfield in rats.

Objective To observe the effects of subacute high altitude hypoxia and the mechanisms on neuronal apoptosis in the hippocampal and the expression of caspase-3 in hippocampus CA1 subfield with in rats.Methods Forty-eight adult male Wistar rats were randomly divided into two groups and moved to different altitude environment(400 m,4 300 m),the animals were sacrificed by decapitation after thirty days.The flow cytometry was used to assay the ratio of apoptosis of hippocampal neurons.The expression of caspase-3 on hippocampal CA1 subfield were observed with immunohistochemistry.The content of malondialdehyde(MDA),the activity of superoxide dismutase(SOD) in hippocampal tissue,the activity of Ca2+-ATPase and the Ca2+ content in hippocampal tissue were determined.Results Compared with low altitude control group,the ratio of apoptosis neurons and the neuronal number of up-regulated expression of caspase-3 in the hippocampus subfield significantly increased in the subacute high altitude groups,MDA contents and Ca2+ content in hippocampal tissue increased in the subacute high altitude groups,the activity of Ca2+-ATPase decreased.However,no significant difference was seen in SOD activity in hippocampal tissues of rats between the low altitude control and subacute high altitude groups.Conclusion Stress of high altitude hypoxia may induce the apoptosis of hippocampal neurons,maybe it is related to increased Ca2+content by decreasing the activity of Ca2+-ATPase and increased free radical.