Melatonin protects against cardiac damage induced by a combination of high fat diet and isoproterenol exacerbated oxidative stress in male Wistar rats

In the current study, it was found that high fat diet (60% of total kCal) (H) or/and isoproterenol (I) exacerbated oxidative stress and caused myocardial damage. This was indicated by increased levels of LPO, PCO, abnormal mitochondria and altered activities of metabolic as well as antioxidant enzymes in myocardium of rats. Melatonin at different doses (10, 20 and 40 mg/kg) effectively protected against myocardial damage induced by H or/and I and preserved all of these altered parameters. Morphological analyses showed that combination of H and I treatment led to the extensive myofibril disintegration and neutrophil infiltration. Melatonin at the dose of 40 mg/kg almost completely prevented these pathological alterations. The mechanistical studies have uncovered that the protective effects of melatonin on the myocardial damage induced by H and I are attributed to its direct and indirect antioxidative capacity, i.e., it directly scavenges free radicals and also regulates the gene expression of antioxidant enzymes. Collectively, based on the evidences gathered from the current study, it will not be unwise to suggest that melatonin can serve as an ideal therapeutic agent for those cardiovascular diseases caused by oxidative stress.