MicroRNA-126 regulates the expression of inflammationrelated genes in vascular smooth muscle cells of diabetic rats

Purpose: To investigate the regulatory role of miR-126 in inflammation-associated gene expression in vascular smooth muscle (VSMCs) cells of diabetic rats.Methods: Diabetes was induced in rats by intraperitoneal injection of streptozocin (STZ) at a dose of 50 mg/kg. VSMCs were isolated from the aortic intimal-medial layers of the rats by a standard protocol. Expression of miR-126 was determined by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Transfection was performed with Lipofectamine 2000 reagent.Results: Expression of miR-126 was significantly (p < 0.05) downregulated in the VSMCs of diabetic rats. Similarly, expressions of SOD, APX and CAT were downregulated, while those of COX, LOX and NOS were significantly upregulated in VSMCs. However, transfection-induced miR-126 overexpression in the VSMCs of diabetic rats led to significant (p < 0.05) upregulation of SOD, CAT, APX and downregulation of COX, LOX and NOS. TargetScan analysis revealed that miR-126 exerted these effects by targeting SIRT1 gene. Furthermore, qRT-PCR and western blotting revealed that miR-126 overexpression in diabetic VMSCs caused significant (p < 0.05) upregulation of the expression of SIRT-1.Conclusion: The results indicate that miR-126 regulates the expression of inflammation-related genes by targeting SIRT-1 genes in vascular smooth muscle cells of diabetic rats. Thus, miR-126 may be beneficial in the management of diabetes.