大鼠局灶性脑缺血再灌注后雌二醇的保护作用及其对caspase-3表达的影响

目的观察雌二醇对大鼠局灶性脑缺血再灌注后神经细胞凋亡与caspase-3表达的影响。方法雄性Wistar大鼠72只随机分为假手术组（n=8）、手术对照组和雌二醇组。后两组又根据再灌注时间的不同各分为3、6、12、24h四个小组,每小组8只。线栓法制作脑缺血-再灌注（I/R）损伤模型。缺血2h分别再灌注3、6、12、24h后断头取脑,应用TUNEL染色及SP免疫组织化学方法观察并测定梗死灶体积、凋亡细胞数及caspase3的表达。结果假手术组未发现脑梗死灶和凋亡细胞及caspase-3阳性细胞。雌二醇组较手术对照组脑梗死体积显著缩小（P〈0.05）,凋亡细胞数减少（P〈0.05）;caspase-3表达减弱（P〈0.05）。结论雌二醇通过下调caspase-3的表达抑制脑细胞凋亡,具有脑保护作用。

Protective function of estradiol after cerebral ischemic reperfusion and its effect on the expression of caspase-3 in rats

Objective To study the effect of estradiol on neurocyte apoptosis and caspase-3 expression in rat focal cerebral ischemia tissue.Methods 72 Wistar rats were randomly divided into sham operation(n=8),operation control and estradiol groups. The latter two groups were further subdivided into 3, 6, 12, 24 h time points subgroups (n=8). Cerebral ischemia reperfusion model induced by left middle cerebral artery occlusion (MCAO) for 2 hours of ischemia were killed at 3, 6, 12, 24 h of reperfusion respectively. Cell apoptosis was detected by TUNEL staining. The expression of caspase-3 was determined by immunohistochemistry. Infarction volume was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining.Results Sham operation group had no infarction focus,apoptosis and caspase-3 positive cell. Comparing to operation control group, estradiol group had significantly reduced infarction size, decreased apoptosis and lessened expressions of caspase-3 (all P<0.05).Conclusions Estradiol could inhibit neuronal cell apoptosis by decreasing the expression of caspase-3,playing protective role in brain.