The Effects of Environmental Enrichment on Neuron Apoptosis and Expression of XIAP Following Cerebral Ischemia and Rreperfusion in Mice
丰富环境对脑缺血再灌注小鼠神经细胞凋亡和XIAP基因表达的影响

The aim of the present study is to investigate whether the effects of environmental enrichment on learning-memory deficits are associated with inhibition of apoptotic cell death and up-regulation of XIAP mRNA expression following cerebral ischemia and reperfusion in mice. The adult male ICR mice were established the cerebral ischemia-reperfusion model by repeated fastening bilateral common carotid artery. Control mice received sham surgery, in which the bilateral common carotid artery did not fastened. One day after surgery, the ischemic and sham mice were randomly assigned for enriched environment housing or standard environment housing for 3 or 7 days, and then submitted to spontaneous behavioral testing in open field and learning-memory performance in Morris water maze. DNA damage induced by cerebral ischemia was detected by agarose gel electrophoresis techniques, and the expression of XIAP mRNA was checked by RT-PCR. The Results showed that environmental enrichment after cerebral ischemia significantly improved the learning-memory damage induced by cerebral ischemia. After 4 days of repeat ischemia-reperfusion, obvious DNA ladder and decreased neuron density were observed in hippocampus CA1 of ischemic mice, but disappeared by environmental enrichment. In correspondence with these results, the down-regulated expression of XIAP mRNA in hippocampus of ischemic mice was inhibited by enriched environment housing for 7 days. The findings suggest that up-regulation of XIAP mRNA expression and inhibition of neuron apoptosis maybe associated with the improvement of spatial learning-memory in cerebral ischemic mice after environmental enrichment.