血管内皮生长因子在氧诱导小鼠新生血管中的表达及意义

Expression of VEGF mRNA and protein in oxygen-induced retinopathy in mouse

目的探讨血管内皮生长因子(VEGF)在小鼠视网膜新生血管中的表达及意义。方法对新生c57BL/6N小鼠高氧后相对低氧饲养,诱导产生视网膜新生血管。在出生后12d、17d摘除眼球,应用RT-PCR,Western Blot以及视网膜血管荧光灌注造影技术检测全视网膜VEGF mRNA、蛋白表达水平以及视网膜新生血管的发生程度。结果视网膜血管造影显示高氧造成血管发育受限,相对低氧后产生新生血管。伴随新生血管的发生,VEGF mRNA升高2·3倍;VEGF蛋白含量也升高7·3倍。结论VEGF表达改变与新生血管发生成正相关,其升高也是造成病理性视网膜新生血管发生的机制之一。减少内源性VEGF表达可能成为治疗视网膜新生血管的新方法。

Objective Retinopathy of prematurity （ROP） is a potential eye disease leading to blindness. The main pathology of ROP is retinal new blood vessel formation. This study aimed to investigate the expression and signification of vascular endothelial growth factor（ VEGF）in oxygen-induced retinopathy of mouse and elucidate the possible mechanism of occurrence of neovascularization in retinopathy of prematurity. Methods 104 newborn c57BL/6 mice were randomly divided into oxygeninduced retinopathy group and control group. Fifty-two newborn c57BL/6 mice were exposed to hyperoxia（75% oxygen）for 5 day to induce retinal neovascularization and then returned to normoxia（ room air）. In control group,52 mice were raised in room air. Experimental mice were sacrificed at postnatal day 12 or 17. RT-PCR and Western blot analyses were used for determination of expression levels of retinal VEGF mRNA and its protein respectively. Fluorescein angiography was used to observe morphologic changes of retinal vessels. Results In oxygen-induced retinopathy group,development of new vasculature in retina of mice was inhibited under the condition of high oxygen, and unperfusion area was seen and neovascularization occurred under the condition of relative hypoxia. The expression level of VEGF mRNA in control group was 1.6 times more than that of oxygen-induced retinopathy group（0. 65 ±0.05 vs 0. 40 ±0.02）in postnatal 12-day mice. However,expression of VEGF mRNA increased by 1.7 times in comparison with controls （0. 91 ± 0.02 vs 0. 91 ± 0. 02）because of relative low oxygen in postnatal 17-day mice. Expression of VEGF protein followed a similar pattern. With neovascularization development,expression levels of retinal VEGF mRNA and protein in oxygen-induced retinopathy group increased by 2.3 fold and 7.3 fold respectively course of the VEGF change correlated with the progression of retinal neovascularization. One of the mechanisms retinal neovascularization may be up-regulation of VEGF.