Interactions between Endostatin and Vascular Endothelial Growth Factor (VEGF) and Inhibition of Choroidal Neovascularization

Abstract: This study was designed to evaluate the inhibitory effect of endostatin onchoroidal neovascularization (CNV) in laser-induced rat model. Choroidalneovascularization was induced in Brown Norway (BN) rats by diode-laserphotocoagulation. Rats were randomly divided into five groups (10 animals in each group):endostatin 20mg/kg group, endostatin 10mg/kg group, laser injury group, normal salinegroup and blank control group. The animals were treated with endostatin, normal saline,laser injury or without treatment on day 0 to day 13 after laser photocoagulation. On day 7and 14 after laser photocoagulation, the CNV formation was assessed by fluoresceinangiography and histopathological analysis. VEGF expression in retina was determined byimmunohistochemical assay. In two endostatin groups, the incidence of CNV formation andthe intensity of fluorescein leakage were reduced compared with the two control groups. Nosignificant difference was found between laser injury group and normal saline group. Theexpression of VEGF reached peak at day 7 and then decreased from day 14 afterphotocoagulation. The expression of VEGF was significantly reduced in the two endostaingroups than laser injury group in a dose-dependent way. Endostatin can inhibit the formationof experimental CNV in the rat. Down-regulation of VEGF expression could be one of themechanisms underlying the inhibition of CNV by endostatin.