血小板反应蛋白-1在糖尿病大鼠视网膜微血管中的表达

Expression of thrombospondin-1 in retinal capillaries in diabetic rats

目的研究高糖状态下血小板反应蛋白-1(TSP-1)在视网膜微血管中的表达。方法链脲佐菌素腹腔注射诱导建立大鼠糖尿病动物模型,设立正常对照组。体外培养牛视网膜微血管内皮细胞,免疫组化法进行鉴定。分别于建模后2、4、8周,运用免疫组化及Western blotting检测大鼠视网膜中TSP-1的表达。收集不同时段高糖孵育的内皮细胞,Real-time PCR检测TSP-1mRNA表达的变化。结果TSP-1在糖尿病大鼠视网膜组织的表达随病程而增加;在正常对照组中,TSP-1的表达呈现生理性的年龄-相关性增长,其增加程度远低于相应周龄的糖尿病大鼠。高糖孵育内皮细胞48 h时,TSP-1 mRNA较正常对照增高,在高糖作用5 d时反而下降(P<0.05)。结论TSP-1对维持血管稳态起重要作用。在高糖状态下,TSP-1高表达可能对新生血管的形成起到重要的负反馈作用。

Objective To investigate the expression of thrombospondin-1 （TSP-1） in retinal capillaries in high glucose conditions. Methods Diabetes was induced by intraperitoneal injection of Streptozoticin, and normal control group was established. Bovine retinal capillary endothelial cells were cultured in vitro, and were identified by immunohistochemical method. Immunohistochemistry and Western blotting were employed to detect the expression of TSP-1 in retina of rats 2, 4 and 8 weeks after model establishment. The endothelial cells cultured by high glucose were obtained at different time points, and the mRNA expression of TSP-1 was determined by Real-time RT-PCR. Results Expression of TSP-1 in retinal tissues of diabetic rats increased with disease duration. In the normal control group, the expression of TSP-1 increased at a physiologically age-related manner, hut was far less significant in the degree of increase than the corresponding diabetic rats. TSP-1 mRNA was higher than that in normal control group 48 h after culture with high glucose, while decresed 5 d after culture with high glucose （ P 〈 0.05 ）. Conclusion TSP-1 plays an important role in maintaining the homeostasis of blood vessel. In high glucose conditions, the higher expression may function as an important negative feedback to angiogenesis.