Dynamic Expression of Transforming Growth Factor β1(TGFβ1),Metalloproteinase(MMP-8) and Tissue Inhibitor of Metalloproteinase(TIMP-1) in Myocardial Remodeling

Objective: To study the expression and the effects of metalloproteinase(MMP-8),tissue inhibitor of metalloproteinase(TIMP-1) and transforming growth factor β1(TGFβ1) in pressure overload rats.Methods: Myocardial remodeling model of adult Wistar rats was established by coarctating of abdominal aorta and creating pressure load in left ventricular to cause myocardial remodeling.Expression of MMP-8,TIMP-1,and TGFβ1,and myocardial remodeling index were evaluated in the 2nd,4th,8th and 12th weeks after operation and sham operation.Collagen contents were measured with Masson stained sections of cardiac muscle.Expression of MMP-8,TIMP-1,and TGFβ1was tested with immunohistochemistry SABC method and protein immunoblotting.Results: Myocardial remodeling and fibrosis predominantly occurred in left ventricle of rats in model groups.The left ventricular hypertrophic index,expression of collagen and protein of TGFβ1 were higher in rats of model groups than in rats of sham operation group(P0.01).Expression of protein of MMP-8 elevated in the 2nd,4th and 8th weeks in rats of model groups,which was higher than that in sham operation group,and,then,decreased to the level of sham operation group in the 12th week(P0.01).The expression of TIMP-1 elevated only in the 2nd week after operation(P0.01).Conclusion: The expression elevation of TGFβ1 and MMP-8/TIMP-1 might relate with myocardial remodeling in pressure overload rats.