Investigation on the expression of cardiac matrix metalloproteinases and brain natriuretic peptide during the progression of rat acute myocardial infarction

Objective: To investigate the change of activities of cardiac matrix metalloproteinases-9(MMP-9) and brain natriuretic peptide(BNP),and the relationship of MMP-9 and BNP with ventricular remodeling and heart function during the progression of acute myocardial infarction(AMI) in a rat model.Methods:Forty-eight male Sprague Dawley(SD)rats were divided randomly into control and AMI group.AMI group rats underwent acute myocardial infarction by ligation of the anterior descending cornary artery and were divided randomly into four groups of 1,7,14 and 28 days after infarction.Control group rats were also randomlized into four groups corre-sponding to the four infarcted groups.Heart function and left ventricular remodeling were confirmed by hemodynamic measurements.The rats were killed at 1,7,14and 28 days after MMP-9 and BNP was assessed.Left ventricular weight(LVW)/body weight(BW) ratio,myocardial infarction size and collangen volume fraction(CVF%) were dete mined.Result: Diastolic end pressure of the left ventricular in AMI group(LVEDP) was increased significantly than that in the control group,left ventricular(LV) pressure maximal rate of rising and falling(dp/dtmax and dp/dtmin)was obviously reduced after acute myocardial infarction.MMP-9and BNP activities rose afterinfarction and kept high levels.MMP-9and BNP activities were significantly higher for each timepoint in the infarction rats than those in control group ones(P0.01).BNP in the AMI groups wassignificantly correlated with MMP-9(r=0.81,P0.01).Conclusion: MMP-9and BNP are associatedwith ventricular remodeling and heart function in a rat model of AMI.They may play an importantrole in promoting ventricular remodeling,and perhaps,BNP has effect on expressing of MMP-9.