Resveratrol blocks diabetes-induced early vascular lesions and vascular endothelial growth factor induction in mouse retinas

Purpose: Vessel leakage and loss of pericytes are early signs of diabetic retinopathy (DR), which leads to vision loss. Upregulation of the vascular endothelial growth factor (VEGF) during diabetes plays a key role in mediating these vascular lesions. The aim of this study is to investigate the effects of resveratrol, a natural plant-derived phytoalexin, on vascular damage and VEGF induction in mouse retinas of early diabetes. Methods: Diabetes was induced in C57BL/6 mice by five consecutive-intraperitoneal injections of 55 mg/kg of streptozotocin (STZ). Animals injected with buffer only were used as controls. Beginning 1 month after the fifth injection of STZ or buffer, 20 mg/kg of resveratrol was administered by oral gavage daily for 4 weeks to diabetic and control mice, and all mice were killed 2 months after the injections. We assessed vessel leakage, pericyte loss and VEGF protein expression in mouse retinas of 2-month diabetes compared with controls with or without resveratrol treatment. Results: Diabetes led to increase vessel leakage, pericyte loss and VEGF protein level in the mouse retinas compared with controls; however, these changes were effectively blocked by resveratrol treatment. Conclusion: Our data suggest that resveratrol is effective to decrease vascular lesions and VEGF induction in mouse retinas of early diabetes.