Effects of 17β-estradiol on expression of bcl-2,bax and cell apoptosis after focal cerebral ischemia in rats

Objective To investigate effects of estrogen on cell apoptosis, and the expression of bcl-2 and bax after focal stroke in rats.Methods 36 rats were divided into three groups:2h group,24h group,48h group;Every group was divided into 3 subgroups,they were false operative group,OVX group,OVX+E 2 group;Immunohistochemistry and TUNEL staining technique were used to examine the neuronal apoptosis and the expression of bcl-2 and bax after focal stroke in rats.Results Cell apoptosis were seldomly seen after 2h of ischemia in three sudgroups. Cell apoptosis in OVX+E 2 group were fewer than that in OVX group and in false operative group after 24,48 hours of ischemia;bcl-2 expression can be seen on all time points,its expression decreased with time prolongation,the expression of bcl-2 in OVX+E 2 group was higher than that in other two groups at the same time points;bax expression increased with time prolongation,the expression of bax in OVX+E 2 group was lowere than that in other two groups at the same time points.Conclusion Estrogen promotes the expression of bcl-2,inhibits the expression of bax,decreases cell apoptosis after focal cerebral ischemia,this may be one of the mechanisms in which Estrogen exerts its neuroprotection in focal cerebral ischemia.