Exogenous erythropoietin aggravates retinal neovascularizationin a murine model of proliferative retinopathy.

Background/aim: Erythropoietin (EPO) has been proven recently to be a critical mediator in retinal neovascularization (RNV). Previous studies have indicated that the use of recombinant human EPO (rEPO) is a high risk factor in the development of retinopathy of prematurity. In this study, we aimed to investigate the effect of rEPO administration on RNV and its underlying mechanism in a mouse model of oxygen-induced retinopathy (OIR). Materials and methods: A murine model of OIR was used to generate RNV. After daily intraperitoneal injection of rEPO from postnatal day 12 (P12), mice were euthanized at P17. Whole-mount retina staining was used to indicate the nonperfused area and neovascularization tufts. Preretinal neovascular cells were calculated through hematoxylin and eosin staining. The expression levels of vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS) were detected via western blot analysis. Results: We found that injection of rEPO promoted the severity of RNV. The areas of neovascular tufts and preretinal neovascular cells were increased after administration of rEPO. When mice were injected with rEPO, a dose-dependent upregulation in VEGF and iNOS was observed. Conclusion: The study indicates the proangiogenic role of EPO, suggesting that rEPO contributes to the pathogenesis of RNV.