色素上皮衍生因子对大鼠视神经夹伤模型视网膜组织中Caspase-3和Bax表达的影响

摘要

目的 探讨色素上皮衍生因子对大鼠视神经夹伤模型视网膜组织中天冬氨酸特异性半胱氨酸蛋白酶3(Caspase-3)、Bax表达的影响.方法 90只SD大鼠随机分为空白对照组、模型组、色素上皮衍生因子(PEDF)组,每组30只.除空白对照组外,均建立视神经夹伤大鼠模型,均取左侧眼球为标本,造模成功后,模型组玻璃体腔内注射平衡盐溶液5μl,PEDF组玻璃体内注射PEDF 5μl(浓度0.2μg/μl),模型组和PEDF组1周、2周再分2次分别向玻璃体腔注射平衡盐溶液5μl和PEDF 5μl.3组大鼠均在第3周时取视网膜组织,电镜下观察视网膜组织超微结构的改变,采用免疫组化染色法观察Caspase-3、Bax表达情况,以及视网膜神经节细胞凋亡情况.结果 透射电镜观察模型组与PEDF组同空白对照组相比,均存在线粒体水肿、胞质浓缩轴突肿胀.同模型组相比,PEDF组胞质浓缩轴突肿胀轻,线粒体结构较完整.TUNEL法细胞凋亡监测:空白对照组染色阴性,模型组和PEDF组均可检测到染色阳性的RGCs,PEDF组TUNEL染色阳性的RGCs表达较模型组显著降低(P<0.05).PEDF组Caspase-3呈弱阳性表达,模型组呈强阳性表达,PEDF组Caspase-3光密度值显著低于模型组(P<0.05);模型组、PEDF组Bax表达高于空白对照组(P<0.05),PEDF组Bax表达又低于模型组,差异有统计学意义(P<0.05).结论 Caspase-3、Bax是诱导RGCs细胞凋亡的重要因子,采用PEDF干预治疗能够降低Caspase-3、Bax表达,减轻RGCs损伤.%Objective To investigate the effects of pigment epithelium derived factor (PEDF) on the expressions of Caspase-3 and Bax in retinal tissues of rat models with optic nerve injury.Methods Ninety healthy female SD rats were randomly divided into three groups:blank control group,model group and PEDF group (experimental group),with 30 rats in each group.Except for blank control group,the rat models with optic nerve injury were established in model group and experimental group.After the animal models were successfully established,the left eye was taken as experimental specimen.The balanced salt solution 5μl was injected into vitreous cavity of rats in model group,and PEDF 5μl (0.2μg/μl) was injected into vitreous cavity of rats in experimental group,moreover,the balanced salt solution 5μl and PEDF 5μl was again injectd into vitreous cavity of rats in modle group and experimental group,respectively on 1 week and on 2 week.On the third week,the retinal tissues of rats in three groups were taken,and the ultrastructural changes of retinal tissues were observed by electron microscopy,and the expression levels of Caspase-3,Bax and the apoptosis of retinal ganglion cells were observed by immunohistochemical staining.Results The mitochondria edema and cytoplasm condensed axon swelling were observed in model group and experimental group.TUNEL cell apoptosis monitoring showed that it was negative in blank control group,however,positive staining of RGCs was found in model group and experimental group,moreover,the positive expression levels of RGCs in experimental group were significantly lower than those in model group (P<0.05).The expression of Caspase-3 was weakly positive in experimental group,which was strong positive in model group.the optical density value of Caspase-3 in experimental group was significantly lower than that in model group (P<0.05).Moreover the expression levels of Bax in model group and experimental group were significantly higher than those in blank control group (P<0.05).However the expression levels of Bax in experimental group were significantly lower than those in model group (P<0.05).Conclusion The Caspase-3 and Bax are important factors inducing apoptosis of RGCs cells.The intervention therapy of PEDF can reduce the expression levels of Caspase-3 and Bax so as to relieve the damage of RGCs.