Effect of losartan on ventricular remodeling induced by matrix metalloproteinase-2 after myocardial infarction in rats

Objective To study the effect of the MMP-2 on the protein expression of I,Ⅲcollagen following myocardial infarction in the rats and the intervening effects of losartan.Methods One hundred and ten adult male Sprague -Dawley rats underwent the left descending coronary artery ligation,then were divided randomly into AMI control group(26 cases)and AMI losartan treatment group(24 cases)(30mg·kg-1·d-1) . The rats in these two groups were redivided into 3 sub-groups according to the course of treatment: 1-week,2-week,4-week sub-groups.Eight rats underwent sham operation,and were killed after 4w.Cardiac function and ventricular remodeling were evaluated by echocardiography and morphological examination.The protein expression of I, Ⅲ collagen was assessed by the method of immunohistochemical stain.The protein expression of MMP-2 was examined by immunohistochemistry.Results Compared with sham operated rats,the protein expression of MMP-2 were enhanced in all subgroups (all P0.05).The I/Ⅲ collagen ratio in the noninfarcted myocardium increased subsequently at 2,4 week(all P0.05).In comparison with the AMI control group,the protein expression of MMP-2 were significantly lower in the 2-week and 4-week sub-groups of losartan group(all P0.05).Ⅰ/ Ⅲ collagen ratio were also significantly decreased in the 2-week,4-week sub-groups of the losartan group (all P0.05).Conclusion MMP-2 play,a key role in postinfarction extracellular matix remodeling.Losartan can prevent ventricular remodeling by suppressing the enhanced expression of MMP-2 and reversing the ratio of I / Ⅲ collagen.