Exp Ther Med
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Diabetic retinopathy, a severe complication of diabetes, is the leading cause of blindness in the developed world. This study investigated the effects of quercetin on levels of monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) in serum of rats with diabetic retinopathy, and explored the functional mechanisms of quercetin in the treatment of diabetic retinopathy. Twenty rats with induced diabetes were divided into a model group and a quercetin group, with 10 rats in each group. ⋯ Results of RT-PCR and western blot analysis showed that, compared with the control group, levels of MCP-1, MMP-9 and VEGF mRNA and protein in the retinal tissue of rats in the model group were significantly increased (P<0.01). No significant differences in expression levels of MCP-1 mRNA and protein were found between the model group and the quercetin group, but levels of MMP-9 and VEGF mRNA and protein were significantly decreased in the quercetin group (P<0.01). Quercetin has a certain therapeutic effect on rats with diabetic retinopathy and its effect may be achieved by reducing the expression of MMP-9 and VEGF, but not the inflammatory mediator, MCP-1.