The Role of Apelin in the Retina of Diabetic Rats

PURPOSE Apelin is a novel adipocytokine participating in diabetes, but its role in diabetic retinopathy (DR) is unknown. Our study aimed to investigate the effect of apelin on the proliferative potential in DR along with its antagonist inhibitory effects. PRINCIPAL FINDINGS Strong staining of apelin, co-localized with glial fibrillary acidic protein (GFAP) and vascular endothelial growth factor (VEGF) was observed in the retina of diabetic rats. Apelin, GFAP, and VEGF mRNA and protein levels were significantly increased in the sample's retinas. Moreover, exogenous apelin promoted retinal Müller cell proliferation in vivo. Simultaneously, apelin induced GFAP and VEGF expression. F13A markedly reduced retinal gliosis caused by diabetes. Furthermore, F13A suppressed both GFAP and VEGF expression in vivo. SIGNIFICANCE Our results strongly suggest that apelin is associated with the development of DR and contributes to changes in the retinas of diabetic rats. Apelin induced promotion of cell proliferation lends support to the possibility that apelin may play a role in the progression of DR to a proliferative phase. This possible role deserves further investigation, which may offer new perspectives in the early prevention and treatment of DR.