轴突导向因子-1 mRNA在氧诱导血管增生性视网膜病变中的表达

目的研究高氧诱导的视网膜新生血管模型鼠中轴突导向因子-1（Netrin-1）mRNA的表达差异。方法采用高氧诱导的方法制作鼠视网膜新生血管模型；运用荧光造影视网膜铺片及视网膜切片苏木精-伊红染色观察视网膜新生血管的形态。于出生后第12、14、17d取小鼠视网膜，采用RT-PCR测定Netritt-1mRNA的表达水平。结果模型组视网膜铺片及组织切片可见大量视网膜新生血管形成。出生后12d，模型组与正常组视网膜组织中Netrin-1mRNA表达水平无明显差异；出生后14d，模型组视网膜组织中Netrin-1mRNA表达水平明显上调；出生后17d模型组视网膜组织中Netrin-1mRNA表达水平仍高于正常组。结论模型鼠视网膜新生血管发生过程中，持续缺氧的视网膜组织可能从转录水平增加Netrin-1的表达，从而诱导视网膜新生血管的发生。

Expression of netrin-1 mRNA in retina with experimental retinal neovascularization induced by oxygen

Objective It has been well-known that retinal neovascularization is associated to multiple factors. However, recent research showed that netrin-1 mRNA can promote the neovascularization. This study was to evaluate the expression of netrin-1 mRNA in retina in experimental retinal neovascularization induced by oxygen. Methods Fifty one-week-old C57BL/ 6J mice were divided into control group and hyperoxic group. The mice of hyperoxic group were exposed to 75% oxygen for 5 days and then returned to the room air to induce retinal neovascularization, and the mice in control group were raised in the environment of room air for the same time. The morphological observation of retinal neovascularization was performed using angiography by fluorescein dextran injection under the fluorescence microscope,and the new blood vessels were quantified after 5 days in room air（17-day-old） by counting the vascular epithelial cell nuclei protruding into viteous cavity using HE stain. RT-PCR were used to examine retinal netrin-1 mRNA level in postnatal day 12,14 and 17 respectively. Results A lots of new blood vessels were seen surrounding the optic disk with irregular distribution and large area of non-perfused area and fluorescine leakage in the mouse retina in hyperoxic group. However,in the normal mouse retina,retinal blood vessels showed the network distribution under the fluorescence microscope. The neovascular nuclei protruding into viteous cavity was 17.2 ＋ 2.6 in hyperoxic group, and no similar neovascular nuclea was found in control group. No significant difference was found in retinal netrin-1 mRNA level in postnatal 12 days between hyperoxic group and control group but was significantly higher in postnatal 14-day mice and 17-day mice compared with control mice （ t = 8.61, P = 0. 008 ; t = 7. 12, P = 0. 009）. Conclusion Netrin-1 mRNA level increases in hypoxia murine retina,which may play an important role in inducing retinal neovascularization.