方法：选取健康雄性Wistar大鼠，随机分成糖尿病组和正常对照组(M0)，用链脲佐菌素大剂量一次性腹腔注射诱导1型糖尿病模型。成模后大鼠随机平均分成1mo(M1)，2mo(M2)，3mo(M3)及5mo(M5)组，免疫组织化学法检测VEGF和PEDF在各组大鼠视网膜及脉络膜的表达。

结果：M1大鼠VEGF在视网膜及脉络膜的表达均与M0无明显差别； M2大鼠VEGF在脉络膜有阳性表达(33.3%)，在视网膜的表达与M0无明显差别； M3大鼠VEGF在脉络膜有阳性表达(55.6%)，在视网膜的表达与M0比较有明显差别(33.3%)； M5大鼠VEGF在视网膜及脉络膜阳性表达(88.9%)； M1和M2大鼠视网膜PEDF表达与M0比较无明显差别，各组脉络膜均无PEDF表达； M3和M5大鼠视网膜PEDF表达均较M0减弱，且随病程延长表达逐渐减弱(P<0.05)，各组脉络膜均无PEDF表达； 随着糖尿病病程延长，VEGF/PEDF比值逐渐增大，与M0相比有显著统计学差异(P<0.01)。

结论：随着糖尿病病程的延长，VEGF在视网膜及脉络膜的表达均逐渐增强，而PEDF与之相反，在视网膜的表达逐渐减弱，且VEGF/PEDF比值逐渐增大，提示VEGF和PEDF均与糖尿病病程密切相关。

METHODS: Healthy male Wistar rats were selected and randomly divided into diabetic group and normal group(M0). Type 1 diabetes rat model was induced by being injected of large-dose streptozotocinum(STZ)into abdominal cavity. The retina and choroid of rats was obtained to detect the VEGF and PEDF expressions by immunohistochemistry at 1^st(M1), 2^nd(M2), 3^rd(M3), 5^th(M5)month after diabetes induction.

RESULTS:VEGF expression in retina and choroid of rats had no obvious difference between M1and M0. M2 VEGF expression in choroid was positive(33.3%), while in retina was not significantly different with M0. M3 VEGF expression in choroid was positive(55.6%), and in inner nuclear layer and ganglion cells layer of retina was positive(33.3%). M5 VEGF expression in choroid was and the whole retina positive(88.9%). PEDF expression in retina of rats had no obvious difference between normal group and M1, M2 group, and there was no PEDF expression detected in choroid of all the groups. In M3 and M5 group, PEDF expression in retina was lower than M0, the expression gradually weakened with the extension of the course(P<0.05), and there was also no PEDF expression detected in choroid of all the groups. The ratio of VEGF/PEDF gradually increased with the extended duration of diabetes, and there was significant difference compared with M0(P<0.01)

CONCLUSION: The expression of VEGF and PEDF in retina of rats was related with the diabetes course, VEGF expression in retina and choroid was increased, while PEDF expression was gradually decreased in the course. There was no PEDF expression in choroid, it might because the experimental model was not in proliferative stage.