Enalapril Confers Protective Effect on Isoproterenol-Induced Myocardial Infarction in Rats through Downregulation of Cardiac Troponin, C-reactive Protein, Upregulation of IL-10β as Well as Anti-Oxidant and Anti-inflammatory Activities

Myocardial infarction is an irreversible death of heart muscle secondary due to prolonged lack of oxygen supply. The present study was designed to evaluate the protective effect of enalapril in isoproterenol-induced myocardial infarction in rats using changes in haemodynamic, biochemical, histopathological and immunohistochemistry parameters. Twenty-one male Wistar rats divided into three groups were used where the control (group A) was administered for normal saline which continued for 7 days, group B animals received normal saline for 7 days and thereafter isoproterenol (ISO) at 85 mg/kg on day 8 and 9. Group C animals were pretreated with enalapril (10 mg/kg) for 7 days and thereafter received ISO on day 8 and 9. On day 10, the blood pressure change in the animals were measured and thereafter sacrificed by cervical dislocation. The heart of each rat was removed, homogenized and used to assay for some oxidative stress markers and some antioxidant parameters. In this study, ISO caused myocardial infarction as seen by significant decrease in systolic, diastolic and mean arterial pressure but was corrected by enalapril. Enalapril caused significant increase in the levels of SOD, GPx, GST and GSH but significant decrease in MDA content and H 2 O 2 generation. But reverse was the case for group B animals. Immunohistochemistry showed that ISO caused higher expressions of cardiac C-reactive protein (CRP) and cardiac troponins 1 (CTn1) and decrease in IL-10 β but vice-versa for enalapril. No histopathological changes were recorded for enalapril. The study thus showed that enalapril significantly exhibits cardioprotective effects.