通络明目膏对糖尿病视网膜病变大鼠微血管的保护作用及其作用机制研究

Study on the effect and mechanism of Tongluo Mingmu Cream in protecting microvessels of rats with diabetic retinopathy

目的探究通络明目膏对糖尿病视网膜病变大鼠微血管的保护作用,并分析其可能作用机制。方法选择60例SD大鼠作为实验对象,应用随机数表法将其分为6组,每组各10只。其中,空白组大鼠正常饮食水,阳性对照组、模型组、中药低剂量组、中药中剂量组、中药高剂量组以高脂高糖饮食联合注射2%链脲佐菌素溶液建立糖尿病视网膜病变大鼠模型。实验开始时,中药低剂量组、中药中剂量组、中药高剂量组分别灌胃通络明目膏10、40、60 mg/(kg·d),阳性对照组灌胃等效剂量100 mg/(kg·d)羟苯磺酸钙胶囊,模型组和空白组灌胃等效剂量生理盐水。干预12周后,观察比较各组大鼠视网膜血管周细胞数、血管内皮细胞数、伊文思蓝(EB)渗透量以及视网膜组织中血管内皮细胞生长因子受体2(VEGFR-2)、血管内皮生长因子(VEGF)表达情况。结果中药低剂量组、中药中剂量组、中药高剂量组、阳性对照组大鼠视网膜血管周细胞数显著高于模型组,血管内皮细胞数、EB渗透量显著低于模型组(P<0.05),且中药低剂量组与阳性对照组上述各项指标比较差异无统计学意义(P>0.05),而中药低剂量组、中药中剂量组、中药高剂量组上述各项指标检测结果比较,差异有统计学意义(P<0.05)。中药低剂量组、中药中剂量组、中药高剂量组视网膜组织中VEGFR-2、VEGF累积光密度值显著低于模型组(P<0.05)。中药高剂量组的VEGFR-2、VEGF累积光密度值明显低于阳性对照组(P<0.05)。结论通络明目膏可对糖尿病视网膜病变大鼠微血管发挥良好的保护作用,有效改善大鼠视网膜微血管形态学及通透性,且该保护作用呈一定的量效关系,其作用机制可能与下调VEGFR-2、VEGF表达有关。

Objective To investigate the protective effect of Tongluo Mingmu Cream on the microvessels of rats with diabetic retinopathy,and to analyze the possible mechanism.Methods A total of 60 SD rats were selected as experimental subjects and randomly divided into 6 groups by the random number table method,with 10 rats in each group.The rats in the blank group were fed as usual,while the rats in the positive control group,model group,low-dose Chinese materia medica(CMM)group,medium-dose CMM group and high-dose CMM group were fed with high-fat and high-sugar diet and injected with 2%streptozotocin solution for the establishment of a rat model of diabetic retinopathy.At the beginning of the experiment,rats in the low-dose CMM group,medium-dose CMM group and high-dose CMM group were gavaged with 10,40 and 60 mg/(kg·d)of Tongluo Mingmu Cream respectively,rats in the positive control group were gavaged with the equivalent dose of 100 mg/(kg·d)calcium dobesilate capsules,and rats in the model group and blank group were gavaged with the equivalent dose of normal saline.After 12 weeks of intervention,the number of perivascular cells,the number of vascular endothelial cells,the amount of Evans Blue(EB)permeation,as well as the expressions of vascular endothelial growth factor receptor 2(VEGFR-2)and VEGF in the retinal tissues of rats in each group were observed and compared.Results The number of perivascular cells in the retina of rats in the low-dose CMM group,medium-dose CMM group,high-dose CMM group and positive control group was significantly higher than that in the model group,the number of vascular endothelial cells and EB permeation amount were significantly lower than those in the model group(P<0.05).There were no statistically significant differences between the low-dose CMM group and the positive control group in all the above-mentioned indexes(P>0.05).The results of the above indexes in the low-dose CMM group,medium-dose CMM group and high-dose CMM group,with statistically significant differences(P<0.05).The accumulated optical density values of VEGFR-2 and VEGF in the retinal tissues of the low-dose CMM group,medium-dose CMM group and high-dose CMM group were significantly lower than those of the model group(P<0.05).The accumulated optical density values of VEGFR-2 and VEGF in the high-dose CMM group were significantly lower than those in the positive control group(P<0.05).Conclusion Tongluo Mingmu Cream can well protect the microvessels of rats with diabetic retinopathy,and effectively improve the morphology and permeability of retinal microvessels in rats.This protective effect shows a quantitative dose-effect relationship,and the mechanism may be related to the downregulation of VEGFR-2 and VEGF expressions.