Abstract

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

Dr. Afaf Abbass Sayed Saleh*

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.

Keywords: Melatonin; Isoproterenol; Myocardial infarction; hydroxyl radical; Inflammatory marker.