Inhibitory effect of recombinant human endostatin on choroidal neovascularization in a rabbit model / 中华实验眼科杂志

ABSTRACT

Background Choroidal neovascularization (CNV) is a serious complication of many fundus diseases.A variety of factors are associated with CNV.Research showed that recombinant human endostatin ( rhendostatin ) can arrest the vascular endothelial growth factor (VEGF) pathway and inhibit the proliferation of endothelial cells and angiogenesis.Objective This study was to observe the inhibition of rh-endostatin on experimental CNV.Methods The CNV animal models were created by Argon laser with the wavelength 532 nm to irradiate the inferior retina away optical disc 1-2 DD for 25 spots in 32 eyes of 16 chinchilla rabbits.The laser parameters were as followspower 800 mW,spot diameter 75 μm and time shutter 50 ms.The models were then divided into model control group and rh-endostatin group.Rh-endostatin was intravitreously injected via scleral incision in 16 eyes of 8 model rabbits at 1 week after photocoagulation.Fundus fluorescein angiography (FFA) and optical coherence topography(OCT) were performed at 1,2,4 weeks after photocoagulation respectively.The eyeballs were enucleated and the retinal sections were prepared for the histopathologieal examination,and the contents of VEGF and pigment epithelial derived factor(PEDF) in rabbit vitreous,and blood serum were detected by ELISA at 2,4 weeks after photocoagulation.Results Retinal edema and exudes were seen in 1 week and scarring in 4 weeks after photocoagulation.In rh-endostatin injection group,the hyperfluorescence masses were seen in the background phase and early arterial phase in 42％ (84/200) of spots in the first week.The fluorescence leakage was decreased in the rh-endostatin injection group compared with control group in the second week and ceased at the third week on the FFA after injection.Variety forms of hyperreflective zones were found below the retinal pigment epithelium on the seventh day after photocoagulation.But the partial vessel occlusion and fibroplasias were identified in the rh-endostatin injection group in the third week by the OCT.The histopathological examination showed that the morphological abnormality was mild in the rh-endostatin injection group in comparison with model group.The serum PEDF concentration was significantly elevated but the VEGF/PEDF values in vitreous and serum were declined in rhendostatin injection group compared with model group (P ＜ 0.0 1 ).Conclusions Argon laser photocoagulation could induce the experimental CNV in chinchilla rabbit.Intravitreous injection of rh-endostar can effectively inhibit laser-induced CNV in rabbit.