Effect of L-Arginine and L-NAME on coronary angiogenesis in male diabetic rats

Diabetes is associated with several vascular abnormalities due to abnormal angiogenesis. Vascular endothelial growth factor (VEGF) and nitric oxide (NO) are among the most important angiogenic factors. The aim of this study was to evaluate the effect of L-arginine (L-Arg) and L-NAME on coronary angiogenesis in male diabetic rats. 24 male rats were randomly divided into four groups: (1) control, (2) diabetic, (3) diabetic + L-Arg (50mg/kg/day, ip), (4) diabetic + L-NAME. (10mg/kg/day, ip). After three weeks, blood samples were taken and the apex of the hearts was stained for immunohistochemistry. Coronary angiogenesis expressed as capillary density/mm2 was lower in diabetic group compared to the control group (P 0.05). L-Arg significantly improved capillary density in myocardial tissue in diabetic animals (P 0.05); however, L-NAME did not alter it (P 0.05). It seems that L-Arginine improves coronary angiogenesis in type I diabetic animals through changes of serum angiogenic factors. More studies are needed to clarify the effect of NO agonists in different experimental models of angiogenesis.