中文摘要：

目的：探讨血管内皮生长因子（ⅦGF）在激光诱导的大鼠脉络膜新生血管（CNV）生成中表达的时相变化。 方法：应用532nm倍频激光对30只有色大鼠的实验眼进行视网膜光凝，建立CNV模型，分别于光凝后3d；1，2，3和4wk行荧光素眼底血管造影（FFA）后处死大鼠，摘除眼球，制作组织病理学标本，原位杂交法检测VEGF mRNA表达，免疫组织化学法和免疫荧光染色法检测VEGF蛋白的表达。 结果：正常大鼠视网膜神经节细胞层、内核层、色素上皮层、视网膜及脉络膜血管内皮细胞中均有VEGF mRNA和蛋白表达。光凝后3d，Ⅷ因子阳性的内皮细胞由破裂的Bruch膜长入视网膜下，但尚未形成CNV；光凝后7d，Ⅷ因子阳性的内皮细胞围成的血管样结构，FFA检查可见相应区域有圆盘状荧光素渗漏，表明CNV生成。同时发现，光凝后3d，在光凝区外核层缺损处，增生和移行的色素上皮细胞、色素性巨噬细胞、成纤维细胞和增生的内皮细胞中VEGF mRNA和蛋白的表达呈强阳性；CNV中VEGF mRNA和蛋白在1wk时表达最强（P〈0．01），2wk后其表达迅速下降。 结论：VEGF的表达早于CNV的生成，提示其潜在的重要作用。

英文摘要：

AIM： To investigate the phase change of vascular endothelial growth factor （VEGF） expression in laser-induced choroidal neovascularization （CNV） in rats. METHODS： CNV was induced in 30 eyes of 30 pigmented rats by 532nm laser photocoagulation. The eyes were followed up by fluorescein angiography （FFA） at 3d;1,2,3 and 4wk post-photocoagulation. The expression of VEGF mRNA and protein post photocoagulation were studied by in situ hybridization, immunohistochemistry and immunofluorescence. RESULTS： In normal rat retina, VEGF expression was mainly observed in ganglion cells, inner nuclear layer, retinal pigment epithelial cells and microvessels of the neural retina and choroid. Three days after photocoagulation, Factor VB-labeled endothelial cells grew into the subretinal space through the broken Bruch＇s membrane, but CNV was not detected. CNV was firstly observed on 7d after photocoagulation by FFA and histopathology. VEGF expressed strongly in the lasered lesion, including retinal pigment epithelial cells, pigment-laden macrophages, fibroblast cells and proliferated endothelial cells at 3d. The level of VEGF mRNA and protein expression in CNV was the strongest at 1wk after photocoagulation, and decreased rapidly after 2wk. CONCLUSION： Our findings demonstrate that VEGF expression is prior to CNV formation, which indicates that the key role of VEGF in the formation of CNV. It may be effective for the prevention and treatment of CNV by inhibiting VEGF expression in the early stage of CNV formation.