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    Effects of carvedilol injection on the cardiac function and left ventricular collagen remodeling after myocardial infarction in rats

    ZHANG Jun, JIA Guoª²Liang, WANG Haiª²Chang, ZHANG Rongª²Qing

    Department of Cardiovasology, Xijing Hospital, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM£º To observe the effects of carvedilol injection on the left ventricular function and collagen remodeling of non-infarcted area after myocardial infarction. METHODS£º Six sham operated SD rats served as controls (sham). Fifty rats with a model of myocardial infarction were randomly divided into nine groups. The rats were treated with carvedilol injection (2 mg¡¤d-1 intraperitoneal injection) and/or captopril (2 g¡¤L-1 drinking water). Acute myocardial infarction (AMI) group did not receive any drug treatment. The animals were sacrificed 4 weeks or 8 weeks after coronary artery ligation. The levels of plasma angiotensin ¢ò and plasma aldosterone (by RIA) and left ventricle function (by catheter measuring ) were studied at different times. The collagen content (hydroxyproline levels) and the ratio of type ¢ñ and ¢ó collagen (by immunohistochemical staining) of noninfarcted area were also assessed in all rats at the fourth or the eighth week. RESULTS£º Compared with those of the AMI group, both carvedilol and captopril decreased the levels of plasma and myocardium angiotensin ¢ò and plasma aldosterone at the eighth week ( P<0ª±05) and carvedilol improved systolic and diastolic function (P<0ª±05). Compared with those of the sham group, both collagen content (hydroxyproline levels) and the ratio of type ¢ñ/¢ó collagen of noninfarcted area (including the infarct border) increased in AMI 4 and AMI 8 group (P<0.05) . The hydroxyproline levels and the ratio of type ¢ñ/¢ó collagen significantly decreased after carvedilol and/or captopril treatment compared with those of the AMI group at the fourth or the eighth week (P<0.05). CONCLUSION£º Carvedilol can improve the cardiac function after myocardial infarction and has beneficial effects on the left ventricular collagen remodeling . ......