| IntroductionVentricular remodeling after acute myocardial infarction (MI) is one of the most common phenomenon, which can lead to ventricular dilatation and heart failure finally. It is now becoming increasingly clear that matrix metalloproteni-nases (MMP) is involved in the pathogenesis of cardiovascular disease, including atherosclerosis, restenosis, dilated cardiomyopathy, in particular MI some studies have shown that the important role of MMP in ventricular remodeling process after myocardial infarction. Since recent studies documented the level of MMP - 2, MMP - 9, tissue inhibition of metalloproteinase( TIMP) ,Collagen I and Collagen Iff raise after MI. Based on these data, this experiment was made to detect the expression of MMP - 2, MMP - 9, TIMP - 1, Collagen I and Collagen HI in myocardial interstitium after MI and after MI treatment by telmisartan so as to evaluate the roles MMP may play in MI and further confirm the protective action of telmisartan in ventricular remodeling after MI.Material and Methods1. Animal and group division; Forty healthy SD rats weighing 250g ~ 300g were randomly divided into three groups: AMI group, telmisartan treatment group and MI group.2. Building of MI model: MI group and telmisartan treatment group rats received isoprenaline (7mg. kg-1) ,and repeated after 24 hours. It was estimated success through rising of the ST - Segment in electrocardiogram. Telmisartan groups rats were treatment with telmisartan (3mg. kg-1 . d-1 ) after MI.3. Assay of MMP -2,MMP -9,TIMP,Collagen I and Collagen Iff immuni-zation chemicobiological MMP -2,MMP -9,TIMP,Collagen I and Collagen I were detected using SABC immunization method and the levels of MMP - 2, MMP - 9, TIMP, Collagen I and Collagen HI were obtained from OD values through computer.4. Statistical analysis ;The data were expressed as mean SE. Statistical a-nalysis was performed by analysis of SPSS 10.0 system.Results1. Change of MMP -2 and MMP -9: MMP -2 and MMP -9 in MI group and telmisartan treatment group were significantly higher than that of control group ( p < 0. 05 ). While the level of treatment groups were significantly lower than that of MI group( p <0.05 ).2. Change of TIMP - 1: The level of TIMP - 1 in MI group and treatment group were higher than that of control group (p < 0. 05 ) . There were no significant difference between MI group and treatment group(p <0.05) .3. Change of Collagen I Collagen III and the proportion of Collagen I and collagen IE : Not only collagen level in MI group and treatment group were higher than that of control group(p <0.05) ,but also the level in treatment group was lower than that of MI group. The proportion of collagen I and collagen III in MI group was higher than that of control group and treatment groups and there was no significant between control group and treatment groups (p >0. 05).DiscussionIn this study, we observed that the increase of MMP - 2, MMP - 9 TIMP, collagen I and collagen HI expression after MI. In addition, telmisartan treatment could decreased the level of MMP -2, TIMP, Collagen I and collagen III Recent experiment studies had reported that MMP may potentially contribute to ventricular remodeling in the post - MI period. MMP - 2 and MMP - 9 over expression is implicated in the vascular remodeling events proceeding plaque rupture (the most common cause of acute myocardial infarction). It can create in-crease of the level of collagen I and collagen III, and play a important role in ventricular remodeling. The present study demonstrated that myocardial MMP activation could occur with the MI region in the absence of reperfusion. There have been a number of previous studies that have identified a mechanistic role of MMP action in the myocardial remodeling process after MI.It was shown in this study that TIMP level of MI groups increased significantly. Total MMP activity is determined by the amount of the activated enzyme and the abundance of the endogenous TIMP. TIMP bind to activated MMP in sto-ichiometric ratio... |
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