Expression and significance of MiR-126 and VEGF in proliferative diabetic retinopathy

OBJECTIVE: To study the expression and significance of micro ribonucleic acid (miR)-126 and vascular endothelial growth factor (VEGF) in the vitreous body and proliferative membrane tissues of affected eyes and plasma in proliferative diabetic retinopathy (PDR). PATIENTS AND METHODS: A total of 50 PDR patients admitted to our hospital from January 2017 to January 2018 were collected, including 17 cases in stage IV, 20 cases in stage V, and 13 cases in stage VI according to the DR staging criteria. Another 30 patients with an idiopathic macular hole were selected as control group. After admission, the examinations were performed, venous blood was drawn, and vitrectomy was performed, during which the vitreous body and proliferative membrane tissues were taken. The plasma VEGF content was detected via enzyme-linked immunosorbent assay (ELISA). The VEGF protein expression level was detected via Western blotting in vitreous body and proliferative membrane tissues. Moreover, the miR-126 expression was detected via quantitative polymerase chain reaction (qPCR). RESULTS: In the vitreous body tissues, proliferative membrane tissues and plasma, the expression level of miR-126 was significantly lower in control group than that in stage IV, V, and VI groups (p<0.05). The miR-126 expression was significantly lower in stage IV group than that in stage V and VI groups (p<0.05), meanwhile, miR-126 expression was significantly lower in stage V group than that in stage VI group (p<0.05). In the vitreous body tissues, proliferative membrane tissues and plasma, the VEGF mRNA and protein expression levels were significantly higher in control group than those in stage IV, V, and VI groups (p<0.05). The VEGF expressions were significantly higher in stage IV group than those in stage V and VI groups (p<0.05). In addition, VEGF expressions were significantly higher in stage V group than those in stage VI group (p<0.05). Furthermore, the VEGF expression level was negatively correlated with the miR-126 expression level. CONCLUSIONS: We found that the abnormally high expression of miR-126 negatively regulates VEGF, which may be one of the important mechanisms of occurrence of PDR. The miR-126 and VEGF content can serve as important predictors for the condition of PDR.