Acute treatment with metformin improves cardiac function following isoproterenol induced myocardial infarction in rats

Background: it has been proposed that metformin exerts protective effects on ischemic hearts. in the present study,we evaluated the effects of metformin on cardiac function,hemodynamic parameters,and histopathological changes in isoproterenol-induced myocardial infarction (mi). methods: male wistar rats were divided into six groups (n = 6) of control,isoproterenol (100 mg/kg; mi),metformin alone (100 mg/kg; sham),and metformin (25,50,100 mg/kg) with isoproterenol. subsequently,isoproterenol was injected subcutaneously for two consecutive days and metformin was administered orally twice daily for the same period. results: isoproterenol elevated st-segment and suppressed r-amplitude on ecg. all doses of metformin were found to significantly amend the ecg pattern. isoproterenol also caused an intensive myocardial necrosis along with a profound decrease in arterial pressure indices,left ventricular contractility (lvdp/dtmax) and relaxation (lvdp/dtmin),and an increase in left ventricular enddiastolic pressure (lvedp). histopathological analysis showed a marked attenuation of myocyte necrosis in all metformin treated groups (p < 0.001). metformin at 50 mg/kg strongly (p < 0.01) increased lvdp/dtmax from 2988 ± 439 (mmhg/s) in the mi group to 4699 ± 332 (mmhg/s). similarly,treatment with 50 mg/kg of metfromin lowered the elevated lvedp from 27 ± 8 mmhg in the myocardial infarcted rats to a normal value of 5 ± 1.4 (mmhg; p < 0.01) and the heart to body weight ratio as an index of myocardial edematous from 4.14 ± 0.13 to 3.75 ± 0.08 (p < 0.05). conclusion: the results of this study demonstrated that a short-term administration of metformin strongly protected the myocardium against isoproterenol-induced infarction,and thereby suggest that patients suffering from myocardial ischemia could benefit from treatment with metformin. copyright © 2012 by institute of pharmacology polish academy of sciences.