17β-雌二醇对大鼠局灶性脑缺血bcl-2、bax表达及细胞凋亡的影响

目的 观察雌激素对大鼠局灶性脑缺血皮层bcl—2、bax表达及凋亡的影响。方法 36只SD雌性大鼠分成3组：2h组、24h组、48h组，每组再分成假手术组，卵巢切除组(OVX组)，17β—雌二醇治疗的卵巢切除组(OVX E2组)。利用免疫组化、原位末端标记方法观察三组大鼠永久局灶性脑缺血皮层bcl—2、bax的表达和细胞凋亡情况。结果 缺血2h，很少出现明显的凋亡细胞，但随缺血时间延长逐渐增多，缺血24h、48h，OVX E2组凋亡细胞较OVX组明显减少；bcl—2在各时间点皆有表达，随缺血时间延长表达逐渐降低，OVX E2组bcl—2表达较同时间点OVX组、假手术组高；随缺血时间延长，bax蛋白表达逐渐增多，OVX E2组bax表达较同时间点OVX组、假手术组降低。结论 脑缺血后雌激素促进bcl—2表达，抑制bax表达，减少细胞凋亡。可能是其脑保护作用的机制之一。

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.