| Objective To study the activities of matrix metalloproteinases(MMPs) and the expression of c - Myc on left ventricular remodeling following myocardial infarction in the rats.At the same time,to abserve the intervening effects and mechanisms of Mongolian Drug RouKouWuWei Pill on ventricular remodeling compared with captopril.Methods Ninety - six male SD rats were randomly divided into normal control group,yocardial infarction group,Captopril group and Mongolian drug group,then the latter separated into three subgroups: low,mid and high dosage.The rats of myocardial infarction group and drug - treated groups were given isoproterenol(ISO) and successful models were judged by Electrocardiogram. Subsequently drug- treated groups were orally given captopril 50mg/kg·d,low dosage Mongolian drug 0.2g/kg·d,mid dosage 0.5g/kg·d and high dosage 1g/kg·d respectively until this experiment terminal.Control and myocardial infarction group was given the same volume N.S.Six rats were killed each group on 1d,7d,28d after administering drugs.Left ventricular weight indexes were calculated and the activities of MMPs were measured by zymography. Proto - oncogene translated protein c - Myc was studied by immunohistochemical staining.The pathologic change of myocardium was observed with microscope.Results(1) Left ventricular weight index in the myocardial infarction group increased significantly compared with normal control(p＜0.01,p＜0.05).It was decreased in every drug- treated groups.(2) The activities of MMP - 2,MMP - 9 in the myocardial infarction group increased compared with normal control.The activity of MMP - 2 in Mongolian drug high dosage group decreased by 3.6%,7.8%(p＜0.05),4.1%(p＜0.05)on 1d,7d,28d respectively compared with myocardial infarction group and MMP - 9 decreased by 1.7%,3.6% (p＜0.05),3.6%(p＜0.05).(3) Immunohistochemical staining showed the expression of c - Myc in the myocardial infarction group increased significantly compared with normal control (p＜0.01),and expression of c - Myc decreased significantly in captopril group and Mongolian drug mid,high dosage group compared with myocardial infarction group(p＜0. 01,p＜0.05,p＜0.05).(4)In control,myocytes were normal,but the structure of cardiac muscle was destroyed in the myocardial infarction group rats by microscope.There were cell nucleus condense and cataclasm in myocytes of infracted region.Conclusion The activities of MMPs in the interstitium increased in some trends following myocardial infarction,and this change may be one of the major causes of ventricular remodeling.The expression of c-Myc increased in the early stage of ventricular remodeling,which suggest c - Myc relate to ventricular remodeling.Captopril and Mongolian drug can decrease the expression of MMPs and c - Myc,so effects of Mongolian Drug RouKouWuWei Pill on the activities of MMPs and expression of c - Myc may be one side of mechanisms on the ventricular remodeling following myocardial infarction. |
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