方法：将双丹明目胶囊作用于糖尿病视网膜病变大鼠，通过与正常组、模型对照组、阳性对照组的比较，电镜下观察双丹明目胶囊对糖尿病视网膜病变大鼠视网膜组织的影响，HE染色后光镜下观察视网膜结构，并采用免疫组织化学法检测大鼠视网膜中VEGF的表达。

结果：经双丹明目胶囊治疗2mo后，双丹明目组大鼠视网膜组织轻度水肿，毛细血管周细胞水肿，线粒体轻度肿胀，结构稍欠清晰，部分内皮细胞轻度增生。除正常组外各组视网膜VEGF表达增加，以模型对照组最为明显，且双丹明目组和阳性对照组与模型对照组VEGF的表达有明显差异(P<0.01)。

结论：双丹明目胶囊能有效地改善糖尿病大鼠视网膜微血管改变，减轻视网膜各层结构水肿、坏死情况，改善超微结构改变，可以抑制DR大鼠视网膜VEGF表达。

METHODS: DR rats were fed with Shuangdanmingmu capsule. By comparing with the normal group, the model control group, and positive control group, the effect of Shuangdanmingmu capsule on retinal tissue of DR rats was observed under electron microscopy. After HE staining, retinal structure was observed under the light microscope. Immunohitochemical staining was used to detect the VEGF expression in retina.

RESULTS:Two months after treatment, the layers tissue of retina presented mild edema, capillary pericytes performed edema, mitochondria showed mild swelling and less clear structure, some endothelial cells showed slight proliferation in Shuangdanmingmu group. Compared with the normal group, the expression level of VEGF in retina increased in the other groups, especially in model control group. A significant differential in expression of VEGF was found between Shuangdanmingmu group, positive control group and model control group(P<0.01).

CONCLUSION: Shuangdanmingmu capsule can effectively improve the retinal microvascular, reduce edema and necrosis of each layer of retina, improve the ultrastructure of retina's tissue and inhibit VEGF expression in DR rats.