Myocardial Protective Effects of Nicorandil on Rats with Type 2 Diabetic Cardiomyopathy

BACKGROUND Diabetic cardiomyopathy (DCM) is a common but underestimated cause of heart failure in patients with diabetes. This study investigated the myocardial-protective effects of nicorandil (Nic) on rats with DCM. MATERIAL AND METHODS A total of forty-seven 180-220 g male Wistar rats were randomly divided into 4 groups: a control group (control, n=8), a DCM group (DCM, n=13), a nicorandil-pretreated DCM group (Nic1, n=13), and a nicorandil-treated DCM group (Nic2, n=13). A rat model of type 2 diabetes was induced by high-fat and high-sugar diet and intraperitoneal injection of streptozotocin (STZ). Nicorandil (3 mg/kg/d) was orally administrated to rats in the Nic1 group starting at week 4. Nicorandil (3 mg/kg/d) was orally administrated only after the induction of diabetes in the Nic2 group. The serum lipoids, plasma glucose, insulin levels, heart weight index, serum creatine kinase (CK), lactate dehydrogenase (LDH) levels, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) were analyzed in all groups. RESULTS The DCM group showed increased heart weight index, serum LDH, CK, and MDA content and decreased serum SOD activity, as compared with the control group (P<0.05). The DCM-induced increases in heart weight index, serum LDH, CK, and MDA content and decrease in serum SOD activity were attenuated in both Nic1 and Nic2 groups (P<0.05). However, there was no significant difference between Nic1 and Nic2 groups (P>0.05). CONCLUSIONS Nicorandil has protective effects on cardiac hypertrophy in DCM rats through increased SOD activity and decreased MDA content. Therefore, nicorandil may be a therapeutic method for diabetic patients with DCM.