Cardioprotective activity of shilajit in isoproterenol - induced myocardial infarction in rats: A biochemical and histopathological evaluation

Abstract

The cardioprotective effects of shilajit in isoproterenol (ISO) induced cardiotoxicity and the antioxidant activity involved in this protection were investigated in rats. Myocardial infarction was produced in rats with 65, 85, 120 and 200 mg/kg of ISO administered subcutaneously (sc) twice at an interval of 24 h. ISO at the dose of 85 mg/kg was selected for the present study as this dose offered significant alteration in biochemical parameters and moderate necrosis in heart. Effect of shilajit oral pretreatment for 91 days at two different doses (250 & 500mg/kg body weight) were evaluated against ISO (85 mg/kg, sc) induced cardiac necrosis. Levels of marker enzymes such as serum glutamic-oxaloacetic transaminase (SGOT), serum glutamic-pyruvic transaminase (SGPT), Lactate dehydrogenase (LDH) and creatinine kinase (CK) were assessed in serum and heart homogenate, other biochemical parameters viz., reduced glutathione (GSH), Lipid Hydro Peroxide (LHP), Lipid per oxidase (LPO) were also assayed in serum and heart homogenate. Significant myocardial necrosis, depletion of endogenous antioxidants and increase in serum levels of marker enzymes were observed in ISO-treated animals when compared with the normal animals. Shilajit elicited a significant cardioprotective activity by lowering the levels of serum marker enzymes and lipid peroxidation and elevated the levels of GSH. The present findings have demonstrated that the cardioprotective effects of Shilajit in ISO-induced oxidative damage may be due to an augmentation of the endogenous antioxidants and inhibition of lipid peroxidation of membrane.