Melatonin protects against streptozotocin-induced diabetic cardiomyopathy by the phosphorylation of vascular endothelial growth factor-A (VEGF-A).

The aim of the present study is to investigate if the melatonin has any protective effect on diabetic cardiomyopathy and antioxidant enzymes via phosphorylation of vascular endothelial growth factor-A (VEGF-A). A total of 40 male Wistar rats were enrolled in the study. Rats were divided into four groups: group 1 (control, n=10), group 2 (DM, n=10), group 3 (melatonin, n=10), and group 4 (melatonin DM, n=10). Melatonin was injected intraperitoneally at a dose of 50 mg/kg/day for 56 days to group 3 and group 4. We investigated expression and phosphorylation of the VEGF-A in coronary vessels of all groups. Staining intensities, biochemical, immunohistochemistry analysis, and transthoracic echocardiography were performed. In comparison to the group 1, DM induced a decrease in p-VEGF-A in coronary vessels of group 2. The lower constitutive phosphorylation of VEGF-A in the group 2 was also increased in coronary vessels after melatonin treatment (p<0.05). Diabetic rats developed myocardial hypertrophy with preserved cardiac function (p<0.05). Cardio-protective effect of melatonin may reduce the damages of diabetes mellitus on the heart muscle fibers and coronary vessels via the phosphorylation of VEGF-A. Melatonin-dependent phosphorylation of VEGF-A in coronary angiogenesis may be associated with the physiological as well as with the pathological cardiac hypertrophy.