雌激素对慢性高眼压兔视网膜损伤的保护作用

摘要

目的 探讨雌激素对慢性高眼压兔视网膜损伤的保护作用.方法 18只成年健康新西兰雌性大白兔随机分为去势组和假去势组.去势组切除两侧卵巢,假去势组仅切除卵巢周围部分脂肪组织.利用前房注射复方卡波姆建立兔慢性高眼压模型.采用末端脱氧核酸转移酶介导的脱氧三磷酸尿苷缺口末端标记法(TUNEL)检测视网膜组织中凋亡细胞的表达;免疫组织化学方法检测B细胞淋巴瘤/白血病(bcl)-2、bax蛋白的表达情况;应用计算机图像分析系统对检测结果进行分析.结果 造模后4、6、8周,去势组较假去势组视网膜神经节细胞数目明显减少,视神经纤维层和内核层变薄;TUNEL阳性细胞表达均较假去势组高(t=3.285,4.012,3.624;P值均<0.01);视网膜bcl-2表达均较假去势组低(t=4.256,3.867,3.459;P值均<0.01);bax阳性细胞表达情况均较假去势组高(t=3.211,3.625,3.253;P值均<0.01).bcl-2的表达与TUNEL的表达呈负相关,凋亡细胞随着bcl-2的表达增多而减少,bcl-2抑制了凋亡的发生.bax的表达与TUNEL的表达呈正相关,凋亡细胞随着bax的表达增多而增多,bax诱导了凋亡的发生.结论 雌激素对慢性高眼压兔视网膜损伤有神经保护作用,这一保护作用主要是通过减少视网膜组织中的凋亡细胞而实现的.%Objective To investigate the protective effects of estrogen on rabbit retinal damages induced by chronic ocular hypertension. Methods A total of 18 white New Zealand female rabbits were randomly divided into ovariectomized (OV) group and sham OV (SOV) group. Bilateral ovaries were remove in OV group while only the adipose tissue around ovarian were remove in SOV group. Chronic ocular hypertension was induced by anterior chamber injection of carbomer. Retinal cell apoptosis was measured by terminal deoxynucteotidyl transferase-mediated dUTP nick end labeling (TUNEL), the expression of bcl-2,bax were detected by immunohistochemistry. The images were captured under microscope and analyzed with computer-image-analysis system. Results Four, six and eight weeks after ocular hypertension modeling,the OV retinas have less retinal ganglion cells, thinner optic nerve fiber layer and inner nuclear layer and more TUNEL positive cells (t = 3. 285, 4. 012, 3. 624; P< 0.01). The OV retinas also have less bcl-2 expression (t=4. 256,3. 867,3. 459;P<0. 01), more bax positive cells (t=3. 211,3. 625,3. 253;P<0. 01).Bcl-2 expression was negatively correlated with TUNEL positive cells indicating bcl-2 can inhibit apoptosis.Bax expression was positively correlated with TUNEL positive cells indicating bax induce apoptosis.Conclusion Estrogen has a neuroprotection role to rabbit retina under chronic ocular hypertension by reducing apoptosis.