Experimental study on the inhibitory effect of bevacizumab on choroidal neovascularization in rat

Abstract

Objective To observe the inhibitory effects and characteristics of intravitreal injection with bevacizumab on laser-induced choroidal neovascularization (CNV).Methods Twelve male brown norway (BN) rats were divided into the bevacizumab group and control group with six rats in each group.One eye of rats were received a series of 8 diode laser esions around optic disc to induce CNV,then the rats in bevacizumab group and control group underwent intravitreal injection with 2 μl bevacizumab and ringer's lactate.On days 7,14,and 21,the morphology and leakage of CNV were observed by fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA).On day 21 after photocoagulation,thephotocoagulated eyes were enucleated and processed for histopathologie examination,including hematoxylin and eosin (H&E) staining and immunohistochemistry staining for vascular endothelial growth factor (VEGF).Results On day 7 after photocoagulation,ICGA showed that CNV developed in the bevacizumab group and the control group.FFA showed that leakage intensity in the bevacizumab group was significantly lower than that in the control group,but the bevacizumab group gradually increased over time.The mean thickness of CNV significantly decreased in the bevacizumab group.The CNV in the bevacizumab group were negative for VEGF according to the result of immmuohistochemistry staining.Conclusions Early intravitreal injection with 2 μl bevacizumab can reduce the thickness of CNV and inhibit the leakage of CNV.However,bevacizumab could neither block the formation of CNV,nor suppress the permeability permanently.Combined other therapies with bevacizumab may be more potential to treat CNV effectively. Key words: Choroidal neovascularization/drug therapy; Angiogenesis inhibitors/therapeutic use; Antibodies,monoclonal/therapeutic use; Antibodies,monoclonal/administration & dosage; Disease models,animal