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目的分析氧诱导视网膜病变动物模型血管内皮生长因子(VEGF)基因的调节规律,阐明早产儿视网膜病变(ROP)新生血管形成的可能机制。方法将36只7d龄C57BL/6J幼鼠暴露在(75±2)%浓度的高氧状态下5d,随后在正常氧环境下5d,作为氧诱导模型组;另24只同日龄幼鼠作为正常对照组。采用荧光素血管灌注及视网膜铺片法观察视网膜血管形态;半定量逆转录-聚合酶链反应(RP-PCR)观察各组VEGFmRNA的变化。结果氧诱导模型的视网膜血管形态特征为高氧状态下表层和深层血管的中心区出现无灌注,相对低氧状态下2d后开始出现新生血管,其部位在中周部。RF-PCR结果显示,VEGF的表达与眼内新生血管的发生存在明确的时空对应关系,即高氧状态下,VEGFmRNA转录下降,相对低氧状态下,VEGFmRNA过度转录。结论缺氧是视网膜新生血管发生的主要原因;高氧之后的相对低氧使VEGF表达增加,可能会降低ROP新生血管的发生。
OBJECTIVE: To analyze the regulation of vascular endothelial growth factor (VEGF) gene expression in animal model of retinopathy of oxygen-induced retinal neovascularization and to explore the possible mechanism of neovascularization in retinopathy of prematurity (ROP). Methods Thirty-six 7-day-old C57BL / 6J infants were exposed to hyperoxia (75 ± 2)% for 5 days, followed by normal oxygen for 5 days, then used as oxygen-induced model group. Control group. The morphology of retinal vessels was observed by fluorescein perfusion and retinal tamponade. The changes of VEGF mRNA in each group were observed by semi-quantitative reverse transcription-polymerase chain reaction (RP-PCR). Results The morphological changes of retinal vessels in oxygen-induced model showed no perfusion in the central area of superficial and deep vessels under hypoxic condition. The neovascularization began to appear after 2 days in hypoxic condition, with the part located in the middle part. The results of RF-PCR showed that there was a clear spatial-temporal relationship between the expression of VEGF and the occurrence of neovascularization in the eye. That is to say, the expression of VEGF mRNA decreased in hypoxia and VEGFmRNA was overexpressed in hypoxia. Conclusion Hypoxia is the main reason of retinal neovascularization. The relative hypoxia after hyperoxia increases the expression of VEGF, which may reduce the occurrence of ROP neovascularization.