ABSTRACT
Background To suppress vascular endothelial growth factor (VEGF) is a researching hot topic for the treatment and prevention of retinal neovascularization.Some detectable efficacy of VEGF small interference RNA (VEGF siRNA) in anti-tumor neovascularization has been well-known.But relevant study on VEGF siRNA on retinal neovascularization is seldom.Objective Present study was to investigate the inhibiting effect of VEGF siRNA on retinal neovascularization.Methods The 48 clean C57BL/6J mice aged 7-day-old were randomly divided into normoxia group,hypoxia control group,vector group and VEGF siRNA group and 12 mice for each.Hypoxia models were established by raising the pups with mother mice in the airtight oxygen-cabin for 5 days.The lipofectamineTM 2000 (LF2000)-mediated vector plasmids or VEGF siRNA recombinant plasmids were then injected intravitreally in 12 12-day-old pup mice respectively.The animals were sacrificed in 1 week after intravitreal injection,and the numbers of vascular endothelial cell nuclei extending beyond the internal limiting membrane (ILM) were counted by hematoxylin-eosin stain.The expressions of VEGF protein and mRNA in retina were assayed by immunoinfluorescence technique and RT-PCR.Results The numbers of vascular endothelial cell nuclei extending beyond the ILM were 0.19±0.09,24.89±2.03,23.65±2.15 and 8.83±1.12 in normoxia group,model control group,vector group and VEGF siRNA group separately,showing significant decrease in VEGF siRNA group compared with model control group or vector group (q=5.67,q=4.97,P＜0.01).RT-PCR revealed that VEGF mRNA was faintly expressed in mouse retina in normoxia group.However,in model control group and vector group,the level of VEGF mRNA was 52.3 times and 36.7 times more than that of normoxia group respectively and only 3.5 times in VEGF siRNA group,presenting a inhibitory rate of 43.39% of VEGF siRNA on VEGF.Immunofluorescence showed that the expression of VEGF was weaker in normoxia group and strong positive response in model control group and vector group,but the expression intensity of VEGF protein was significantly weaker in VEGF siRNA group.Conclusion VEGF siRNA recombinant plasmids can efficiently inhibit retinal neovascularization in oxygen-induced retinopathy mouse model through intravitreal injection.