中文摘要：

背景血管内皮生长因子（VEGF）在血管发育和新生血管形成中起着关键作用。研究表明，组织蛋白酶B（Cathepsin B）参与新生血管的生成，但其具体机制尚不明确。目的探讨Cathepsin B和VEGF在高氧诱导小鼠视网膜新生血管中的表达及二者之间的关系。方法应用随机数字表法将44只7日龄清洁级C57BL/6J小鼠随机分为正常对照组、高氧诱导组、空白对照（NC）-绿色荧光蛋白（GFP）-慢病毒（Lv）组和Cathepsin B-RNA干扰（RNAi）-Lv组，每组11只小鼠22只眼。正常对照组小鼠在自然环境中生长；其余3个组7日龄小鼠置于氧体积分数为（75±2）%的密闭氧箱内饲养5 d，之后返回到正常环境中。高氧诱导组的12日龄小鼠不给予任何药物干预；NC-GFP-Lv组和Cathepsin B-RNAi-Lv组的12日龄小鼠分别给予玻璃体腔注射NC-GFP-Lv和Cathepsin B-RNAi-Lv各1 μl。取各组17日龄小鼠，颈椎脱臼法处死后剥取视网膜，分别采用real-time PCR和Western blot法检测小鼠视网膜中Cathepsin B和VEGF mRNA及蛋白的相对表达量。结果荧光显微镜下Cathepsin B-RNAi-Lv组视网膜新生血管分层和分支均较高氧诱导组和NC-GFP-Lv组少。各组Cathepsin B和VEGF mRNA总体比较，差异均有统计学意义（F＝444.89，P＝0.00；F＝519.78，P＝0.00），其中高氧诱导组、NC-GFP-Lv组和Cathepsin B-RNAi-Lv组小鼠视网膜中Cathepsin B和VEGF mRNA的相对表达量均明显高于正常对照组，Cathepsin B-RNAi-Lv组小鼠视网膜中Cathepsin B和VEGF mRNA的相对表达量均明显低于高氧诱导组和NC-GFP-Lv组，差异均有统计学意义（均P〈0.05）。各组Cathepsin B和VEGF蛋白总体比较，差异均有统计学意义（F＝54.37，P＝0.00；F＝79.65，P＝0.00），其中高氧诱导组、NC-GFP-Lv组和Cathepsin B-RNAi-Lv组小鼠视网膜中Cathepsin B和VEGF蛋白的相对表达水平均明显高于正常对照组，Cathepsin B-RNAi-Lv组小鼠视网膜中Cathepsin B和VEGF蛋?

英文摘要：

BackgroundVascular endothelial growth factor （VEGF） plays a key role in the vascular development and neovascularization.Studies have proved that Cathepsin B is related to the formation of neovascularization, but its mechanism is unclear.ObjectiveThis study was to investigate the expression of Cathepsin B and VEGF in the retinal neovascularization induced by hyperoxia and the relationship between them.MethodsForty-four 7-day-old C57BL/6J mice were randomly assigned into 4 groups： normal control group, hyperoxia-induced group, normal control （NC）-green fluorescent protein （GFP）-lentivirus （Lv） group and Cathepsin B-RNA interference （RNAi）-Lv group, with 11 mice 22 eyes for each group.The mice in normal control group were survival in natural environment.The other three groups of 7-day-old mice were put in a sealed box of oxygen volume fraction （75±2）% for 5 days and then sent back to normal environment.The mice of hyperoxia-induced group did not have any drug intervention, while the 12-day-old mice of NC-GFP-Lv group and Cathepsin B-RNAi-Lv group received intravitreal injection of NC-GFP-Lv 1 μl or Cathepsin B-RNAi-Lv 1 μl.All 17-day-old mice were sacrificed and the retinas were collected.The mRNA expression levels of Cathepsin B and VEGF were performed by real-time PCR; the protein expression levels of Cathepsin B and VEGF were detected by Western blot.ResultsFluorescence microscope results showed that the layer and branch of retinal neovascularization were less in the Cathepsin B-RNAi-Lv group than those in the NC-GFP-Lv group and hyperoxia-induced group.The relative expression levels of Cathepsin B and VEGF mRNA in each group were significantly different （F=444.89, P=0.00; F=519.78, P=0.00）. The relative expression levels of Cathepsin B and VEGF mRNA in hyperoxia-induced group, NC-GFP-Lv group and Cathepsin B-RNAi-Lv group were higher than those in normal control group, and the relative expression levels of Cathepsin B and VEGF mRNA in Cathepsin B-RNAi-Lv group were lower than tho