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DOI: 10.1055/s-0030-1268958
Cardioprotective effect of zinc aspirinate against isoproterenol-induced myocardial ischemia in rats
Oxidative stress, owing to increased production of free radicals and decreased levels of antioxidants in the myocardium plays a major role in cardiovascular diseases. In recent years, zinc complexes have emerged as useful antioxidants. We investigated the effects of zinc-aspirinate on isoproterenol-induced myocardial ischemia in rats and its possible mechanisms.
Rats received vehicle or zinc-aspirinate (100mg/kg) for 5 days. Isoproterenol (85mg/kg) was injected subcutaneously on days 4 and 5 to produce myocardial infarction. After 17–22h, we performed ECG patterns, histological examination and left ventricular pressure-volume analysis to assess cardiac function using a Millar microtip catheter. The effects of zinc-aspirinate on hydrogen peroxide-induced cytotoxicity in cultured cardiomyocytes were investigated. Myocardial mRNA expression was assessed by quantitative real-time polymerase chain reaction.
In isoproterenol-treated rats decreased load-dependent contractility parameters as ejection fraction (65±7%, 37±5%, 57±6%; control, iso, zinc-aspirinate+iso groups respectively), maximal slope of the systolic pressure increment (dP/dtmax, mmHg/s:8757±282, 6615±410, 8332±577; control, iso, zinc-aspirinate+iso groups respectively) and the load-independent, pressure-volume loop derived contractility index, Emax (mmHg/microl:5.1±0.6, 2.6±0.4, 4.6±0.5; control, iso, zinc-aspirinate+iso groups respectively), stroke volume and cardiac output were significantly increased after pre-treatment with zinc-aspirinate. Zinc-aspirinate reduced inflammatory infiltrate into the tissues, reduced cardiomyocytes death in a cellular model of oxidative stress and decreased ST-segment elevation. Moreover, zinc-aspirinate was shown to prevent the decrease in superoxide dismutase 1 mRNA-expression.
Our results show that zinc-aspirinate improves myocardial function against isoproterenol-induced myocardial infarction in rats. Its cardioprotective effects can be explained by the protection of the cell membrane and induction of antioxidant enzymes.