糖尿病大鼠视网膜病变中促血管生成因子的表达及意义

目的：检测血管内皮生长因子(VEGF)和基质细胞衍生因子-1α(SDF-1α)及其受体CXCR-4在糖尿病大鼠视网膜病变(DR)组织中的表达，探讨其在DR发病机制中的作用。 方法：以链脲佐菌素诱导建立糖尿病大鼠模型。随机分为1月病程组(M1)、3月病程组(M3)和5月病程组(M5)。分别进行透射电镜观察视网膜微血管。视网膜消化铺片后行VEGF和SDF-1α/CXCR-4免疫组织化学检测。半定量逆转录聚合酶链反应(RT-PCR)和Western印迹分别检测VEGF，SDF-1α和CXCR-4 mRNA和蛋白在大鼠视网膜中的表达。结果：血管透射电镜观察：正常对照未见异常改变，M1开始出现异常改变，M5最明显。随着病程的延长，免疫组织化学示视网膜中VEGF，SDF-1α和CXCR-4表达水平逐渐增高，与正常对照组相比，造模后M1就有明显增高，M5差异有统计学意义（P<0.05）。RT-PCR示VEGF，SDF-1α和CXCR-4 mRNA的表达造模后M1就有明显增高，M5差异有统计学意义（P<0.05）。Western印迹示VEGF，SDF-1α和CXCR-4的蛋白表达造模后M1无明显改变，M3升高（P<0.05），M5时升高最明显（P<0.05）。 结论：DR时VEGF，SDF-1α和CXCR-4在视网膜中的表达水平随糖尿病病程延长逐步增高，是DR的重要因素。

Expression and meaning of pro-angiogenic factors inretinopathy of diabetic rats

Objective To detect the expression of vascular endotheilal growth factor (VEGF), stromal cell-derived factor-1α (SDF-1α), and its receptor CXCR-4 in the retinopathy of diabetic rats, and to explore the relationship between those factors and diabetic-retinopathy(DR). Methods Diabetes was induced in 40 rats with a single intraperitional injection of streptozotocin(STZ). Experimental rats were randomly divided into M1 (diabetic for 1 month), M3 (diabetic for 3 months), and M5 (diabetic for 5 months) groups, and another 10 rats served as a normal control group (NC). Retinal vascular status was observed by transmission electron microscope. After retinal stretched preparation, VEGF, SDF-1α and CXCR-4 immunohistochemistry were done. Retinal VEGF, SDF-1α, and CXCR-4 mRNA were detected by semi-quantitative RT-PCR. Protein expression was measured by Western blot. Results Under transmission electron microscope, change in vascular status was found in M1 to M5 groups, but not in the NC group. The changes became increasingly serious with the prolongation of the disease. By immunohistochemistry, we found the expression of VEGF, SDF-1α, and CXCR-4 on the retina increased gradually. It increased after injecting STZ for 1 month and increased significantly after 5 months.VEGF, SDF-1α, and CXCR-4 mRNA expression increased obviously after injecting STZ for 1 month and increased significantly after 5 months. Western blot showed that protein of VEGF, SDF-1α, and CXCR-4 had no change after injecting STZ for 1 month. It began to increase in the M3 group and increased most in the M5 group. Conclusion The expression of VEGF, SDF-1α, and CXCR-4 on the retina in retinopathy of diabetic rats increases gradually with the prolongation of the disease. It is an important factor for diabetic retinopathy.