STZ糖尿病大鼠视网膜病变模型的再评价

Revaluation of experimental animal model of diabetic retinopathy induced by STZ rat

目的本研究旨在对链脲佐菌素(STZ)诱导的糖尿病大鼠视网膜病变糖尿病进行系统性的再评价。方法雄性SD大鼠75只,随机分为空白组(30只)和糖尿病组(45只)。采用一次性大剂量腹腔注射STZ60mg/kg的方法制备糖尿病模型,监测6个月,动态考察大鼠的体重、血糖变化,同时测定大鼠的血液流变学参数。视网膜铺片法观察视网膜形态学变化,免疫组化法考察血管内皮生长因子(vascular endothelial growth factor,VEGF)、色素上皮细胞衍生因子(pigment epithelium derived factor,PEDF)表达的变化,Western blotting法观察内皮细胞紧密连接蛋白(occludin)、细胞间粘附分子-1(intercellular adhesion molecule-1,缩写ICAM-1)表达量的变化,分光光度法测定醛糖还原酶(aldose reductase,AR)活性的改变。结果与空白组相比,STZ大鼠全血粘度、血浆粘度、红细胞聚集指数均增加。视网膜血管基底膜增厚,毛细血管退化,有闭锁现象,静脉扩张明显,周细胞数量明显减少。其视网膜中的VEGF表达增加(IOD/area 0.66±0.28,空白组0.25±0.03),PEDF表达减少(IOD/area0.07±0.06空白0.19±0.04),与血-视网膜屏障相关的occludin蛋白表达下降70%,炎症因子ICAM-1增加2.58倍,AR活性升高3倍。结论 STZ糖尿病大鼠视网膜病变发生在多个位点,借助该模型对糖尿病视网膜病变的研究可以从多层次、多角度进行。

Objective The aim of this study is to revaluate the experimental animal model of diabetic retinopathy induced by streptozotocin （STZ） rats systematically. Medthods 75 Sprague- Dawley rats were divided into two groups randomly ： 30 for control and 45 for diabetic. Diabetes was induced by a single injection of 60 mg/kg STZ and monitored for 6 months. Body weight and blood glucose were determined dynamically. Three indexes of hemorheology were assayed. Retinal morphometry were determined by trypsin digest preparations. Expression of vascular endothelial growth factor （VEGF）, pigment epithelium derived factor （PEDF） of retina were analysed by immunohistochemistry. Expression of occludin and intercellular adhesion molecule- 1 （ ICAM-1 ） of retina were measured by Western blotting. The activity of aldose reductase of retina was assayed by ultraviolet spectrophotometry. Results Compared with control group, the whole blood viscosity, plasma viscosity and erythrocyte aggregation index of STZ rats reduced, the basement membrane of retinalvessel thickened, numbers of capillaries degenerated with occlusion, retinal venular caliber dilated, the number of pericytes reduced obviously. The expression of retinal VEGF raised（ IOD/area 0. 66±0. 28 vs control 0. 25±0.03） , the expression of retinal PEDF declined（ IOD/area 0. 07 ± 0.06 vs control 0. 19± 0.04）, occludin protein decreased to 70% , ICAM-1 protein increased by 2. 58 times, the activity of aldose reductase increased by 3 times. Conclusion The diabetic retinopathy model in rat with STZ-induced diabetes occurs in multiple sites, and this animal model can be researched for diabetic retinopathy through multiple aspects and levels.