MELATONIN PRETREATMENT CAN ENHANCE THE PROTECTIVE ACTION AGAINST ISOPROTERENOL - INDUCED ALTERATION ADVERSELY AFFECTING CARDIAC FUNCTION.

Abstract

Myocardial infarction (MI) is the acute condition of necrosis of the myocardium that poses a major public health problem in the world. The purpose of this study was to appraise the possible cardio-protective effects of melatonin against isoproterenol (ISO)- induced MI in rats. Two days after ISO administration to male Wistar rats (150 mg/kg b.wt/day) exhibits cardiotoxicity that is associated with an increase in serum levels of C - reactive protein (CRP) and cardiac troponin - I (cTn - I), as well as excessive production of free radicals along with profound increase in the serum levels of cardiac injury markers, creatinine kinase- MB (CK- MB), lactate dehydrogenase (LDH), aspartate transaminase (AST) and alanine transaminase (ALT), and a significant decrease in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione - S- transferase(GST) and the levels of reduced glutathione (GSH), malondialdehyde (MDA), total nitric oxide (TNO) and myeloperoxidase (MPO). Pretreatment of ISO- injected rats with melatonin at a dose of 10 mg/kg b. wt. daily for 30 days showed a significant decrease in the levels of lipid peroxidation and improved the antioxidant status by increasing the activities of antioxidant enzymes and non - enzymatic antioxidants as well as reduction of inflammatory markers. The results suggested the potential role of melatonin pretreatment to diminish the ISO - induced cardiac injury and possess anti - oxidant and free radical scavenger with cardio- protective properties.