Influence of fluvastatin on left ventricular remodeling after myocardial infarction in rats

Abstract

To investigate the effect of long-term administration of fluvastatin on improvement of ventricular remodeling of rats after myocardial infarction and its mechanism. Sprague-Dawley rats were subjected to ligation in anterior descending branch of coronary artery and treated with fluvastatin (20 mg.kg(-1) d(-1)) or distilled water for 8 weeks. Doppler echocardiography, hemodynamic study and cardiac histomorphometry were used to estimate the ventricular remodeling and cardiac function. Laser scanning confocal microscope was used to definite the distribution of superoxide anion (O(2)(*-)) and nitrogen monoxide. RT-PCR and immunohistochemistry were used to detect the expression of NOS2 and p22phox in mRNA and protein level. The level of lipid peroxidation, glutathione peroxidase, nitrogen monoxide and total cholesterol were detected too. Administration of fluvastatin ameliorated left ventricular remodeling without affecting the infarct size [(40 +/- 6 vs 42 +/-5)%, P>0.05]. The level of left ventricular end-diastolic pressure [(18.24 +/-6.58 vs 10.74 +/-4.71) mmHg, P<0.05], right ventricular ameliorated relative weight [(0.92 +/-0.19 vs 0.71 +/-0.13) g/kg, P<0.05], the thickness of left ventricular posterior wall [(3.04 +/-0.28 vs 2.60 +/-0.36) mm, P<0.05] decreased after fluvastatin treatment. The left ventricular ejection fraction was not influenced, the relative lung weight and the left atrium diameter reduced [(5.79 +/-2.92 vs 3.69 +/-0.68) g/kg, (0.55 +/-0.12 vs 0.45 +/-0.04) mm, P<0.05]; the expressions of LPO in the plasma and myocardium [(8.64 +/-0.59 vs 7.71 +/-0.66) U/dl, P<0.05; (3.12 +/-0.38 vs 1.93 +/-0.40) ng/microg.pro, P<0.01] were reduced, and the overexpressed NO was inhibited [(436.87 +/-47.22 vs 313.78 +/-34.35) mg/dl, P<0.01], but the expression of GPx increased [(66.13 +/-8.31 vs 79.78 +/-2.38) mg/dl, P<0.01]. The expression of O(2)(*-) and the activity of NADPH oxidase subunit p22phox increased; NOS2 and its products NO were over-expressed too. Ventricular remodeling and hemodynamics are improved profoundly in MI rats treated with fluvastatin. The effect of antioxidative stress of fluvastatin might be involved in the mechanism.