Aim To observe the influence of fluvastatin on expression of matrix metalloproteinase-9 (MMP-9) in rats with acute myocardial infarction (AMI) and to investigate the mechanism of statin on improving left ventricular remodeling after acute myocardial infarction. Methods 47 healthy male Wistar rats were randomly divided into AMI group,AMI+fluvastatin group,the sham-operated group (sham) and the sham-operated+fluvastatin group. AMI was established by ligation of the anterior descending coronary artery in rats,fluvastatin was fed to AMI+ fluvastatin group and sham+ fluvastatin group by 10 mg/(kg·d) for 4 weeks while the AMI group and the sham group left untreated,then the hemodynamic parameters and mass index of left ventricular and the expression of matrix metalloproteinase-9 were detected. Results The expression of matrix metalloproteinase-9 and left ventricular end-diastolic pressure (LVEDP)were low in the sham-operated group and the sham-operated+fluvastatin group,and there were no significant difference ( P>0.05). Compared with the shams,the production of matrix metalloproteinase-9 and left ventricular end-diastolic pressure were all increased in the AMI group and AMI+ fluvastatin group (P<0.05),and these indexes were increased significantly in the AMI group than those in the AMI+ fluvastatin group (P<0.05). Compared with the sham-operated group and the sham-operated+fluvastatin group,left ventricular systolic pressure(LVSP) and the maximal rate of rise and fall (±dp/dtmax)of left ventricular pressure in the AMI group and AMI+ fluvastatin group were all decreased (P<0.05),moreover,these indexes decreased significantly in AMI group than those in AMI+ fluvastatin group (P<0.05). The mass index of the left ventricular in each group showed no significant difference ( P>0.05). Conclusions Fluvastatin can inhibit the expression of matrix metalloproteinase-9 to prevent ventricular remodeling after acute myocardial infarction in rats and improve cardic function.