链尿佐菌素诱导的糖尿病鼠视网膜N-钙蛋白的表达

目的 观察链脲佐菌素(STZ)诱导的糖尿病鼠视网膜N-钙粘蛋白(N-cadherin)的表达。 方法 20只Sprague Dawley(SD)大鼠腹腔一次性注射65 mg/kg STZ建立糖尿病模型，另20只SD大鼠腹腔一次性注射等体积枸橼酸盐缓冲液作为对照。伊文思蓝检测视大鼠网膜血管的渗透性；免疫组织化学、Western blotting方法检测对照组及糖尿病组大鼠视网膜及用胰蛋白酶消化的视网膜微血管N-钙粘蛋白表达情况。 结果糖尿病诱导4、8、12 周后视网膜血管渗透性分别增加68%、91%、125%(P<0.005)。对照组视网膜N-钙粘蛋白主要表达在视网膜外网状层、内网状层、内核层、神经节细胞层、内界膜及视网膜微血管内皮细胞和周细胞之间。STZ诱导糖尿病鼠12周后视网膜及视网膜微血管N-钙粘蛋白表达显著下降。Western blotting分析结果显示随着糖尿病视网膜病变的发展，视网膜N-钙粘蛋白表达显著减少。 结论 STZ诱导的糖尿病大鼠视网膜N-钙粘蛋白的表达降低，提示反应性N-钙粘蛋白可能参与早期糖尿病视网膜病变的发生。(中华眼底病杂志,2007,23:269-272) 

Expression of N-cadherin in streptozotocin-induced diabetic rats'retinae

Objective To observe the expression of N-cadherin in streptozotocin (STZ)-induced diabetic Sprague-Dawley (SD) rats′retinae. Methods Celiac injection with 65 mg/kg STZ was performed on 20 rats to set up the diabetic model, and celiac injection with the same volume citrate buffer was performed on other 20 SD rats as the control. Vascular permeability was detected by Evans blue method. The expression of N-cadherin in both normal and STZ-induced diabetic rats′retinae and trypsinase-digested retinal microvessels were detected by immunohistochemistry method and Western blotting analysis. Results Retinal vascular permeability increased 68%, 91% and 125% 4, 8, and 12 weeks, respectively, after diabetic models was induced (P<0.005). In the control group, the expression of N-cadherin was detected in the outer and inner plexiform layer, inner nuclear layer，ganglion cell layer,internal limiting membrane and between retinal endothelial cells and pericytes. However, the expression of N-cadherin significantly decreased in STZ-induced diabetic rats retinae at the 12th week. The results of Western blotting analysis showed that the expression of N-cadherin obviously decreased as the diabetic retinopathy developed. Conclusion The decrease of expression of N cadherin in the retinae of STZ-induced diabetic rats suggests that N-cadherin may participate in the development of diabetic retinopathy at the early stage.(Chin J Ocul Fundus Dis,2007,23:269-272)