The cardioprotective role of melatonin against myocardial injury in patients undergoing coronary artery bypass grafting surgery

BACKGROUND: Myocardial ischemia/reperfusion injury associated with coronary artery bypass graft (CABG) surgery characterizes as a clinically critical problem. The incidence of oxidative stress, inflammation, and apoptosis are induced throughout the reperfusion of the cardiac muscles following ischemia. The present study aims to examine the protective role of melatonin in ameliorating the degree of myocardial injury in patients undergoing bypass surgery, and whether this effect is dose related. PATIENTS AND METHODS: A total of 45 patients who were undergoing CABG in (Al-Najaf Cardiac Center, Al-Najaf, Iraq) were enrolled in this study between January 2015 and November 2015. Patients were randomly allocated into three study groups: placebo-controlled group (C), low-dose melatonin treatment group, 10 mg capsule once daily (M1) and high-dose melatonin treatment group 20 mg capsule once daily (M2). RESULTS: Compared to the control group, there was a significant increase in the plasma level of melatonin associated with a significant reduction in plasma levels of high sensitive C-reactive protein, creatine kinase isoenzyme muscle/brain, and cardiac troponin-I, in the melatonin groups (Group M1 and M2) compared to the control group, (P < 0.05) in melatonin-treated groups. Comparing the two melatonin study groups, the changes in the parameters mentioned above were more significant in the M2 group compared to the M1 group (P < 0.05). CONCLUSION: These findings suggested that melatonin administration can ameliorate the degree of myocardial injury, dose-dependent effects