目的：探讨外源性雌激素对大鼠视网膜缺血再灌注损伤的保护作用机制及对Bcl-2和Bax蛋白表达的影响。 方法：雄性SD大鼠72只随机分为正常组（N，n=8），单纯缺血再灌注组（IR，n=32），苯甲酸雌二醇处理组(E₂+IR，n=32)。其中后两组又分为再灌注后6，24，48和72h组（每组8只）。通过前房灌注加压法建立大鼠视网膜缺血再灌注模型。常规HE染色观察视网膜组织形态变化，免疫组织化学方法检测Bcl-2和Bax蛋白的表达。 结果：E2+IR组视网膜组织损害程度在各时间点较IR组好转。IR组Bax蛋白在6h时已经开始表达，24h达高峰，48h表达开始下降，72h仍有部分表达；而E₂+IR组Bax蛋白的表达在各时间点上较IR组明显下调（P<0.01）；IR组Bcl-2蛋白的表达在再灌注6h时表达量最多，随时间延续表达量逐渐减少；Bcl-2蛋白的表达在各时间点上较IR组明显上调（P<0.01）。 结论：缺血再灌注损伤损害了视网膜组织结构。Bcl-2和Bax参与了视网膜缺血再灌注损伤的调控，苯甲酸雌二醇可上调Bcl-2的表达，下调Bax的表达，保护视网膜组织。

AIM: To investigate the protective effects of exogenous estrogen and effects on expression of Bcl-2 and Bax protein against retinal ischemia-reperfusion injury(RIRI)． METHODS:Seventy-two SD rats were randomly divided into normal control(N,n=8),simple ischemia-reperfusion model group(IR, n=32),estradiol benzoate treatment group (E₂+IR,n=32).In the latter two groups,each sub-group was determined by the time after ischemia-reperfusion: 6, 24, 48 and 72 hours. By improving the anterior chamber intraocular pression to set up ischemia-reperfusion model in big rats.The morphology change of retina tissue was detected by light microscope.The changes of Bcl-2, Bax protein were measured by immunohistochemistry in retinal tissue . RESULTS:.In the E₂+IR group, the damage of the retina was significantly reduced than IR group.In IR group,the expression of Bax protein began to add at 6 hours after reperfusion,24 hours reached the peak,48 hours began to reduce,and 72 hours had weak expression. In IR group the expression of Bcl-2 reached the peak at 6 hours,with time going,the expression of Bax began to reduce;but in E2+IR group were increased significantly than IR group in all the time points(P<0.01). CONCLUSION:The retina organization was injured by ischemia-reperfusion injury.Bcl-2 and Bax protein had taken part in the RIRI. Estradiol benzoate could increase the expression of Bcl-2 and cut the expression of Bax protein, and protect the retina tissue.