AIM:To observe the effect of Huang Qi injection on left
ventricular function and collagen remodeling of noninfarcted area
myocardial infarction.Prolonged inotropic stimulation with digoxin during healing after myocardial infarction increased infarct bulging. Huang Qi is an inotropic durg, but its effect on left
ventricular remodeling is unknown. METHODS: Ten sham operated SD rats served as controls (sham). Eighty-eight rats with a moderate to large myocardial infarction were randomly divided into eight groups. The rats were treated with Huang Qi injection (2 mg/d intraperitoneal injection) and/or captopril (2g/L drinking water).Acute myocardial infarction(AMI) group did not receive drug treatment. The animals were sacrificed at 2 weeks or 6 weeks after coronary artery ligation. The levels of plasma and myocardial
angiotensin Ⅱ and plasma aldosterone (by RIA) and left ventricle function (by catheter measuring) were studied at different time. The collagen content(hydroxyproline levels) and the ratio of type Ⅰand Ⅲ collagen (by immunohistochemical staining) of noninfarcted area were also assessed in all rats at the second or the sixth week.RESULTS:Compared with AMI groups, both Huang Qi and captopril decreased the levels of plasma and myocardium angiotensin Ⅱ and plasma aldosterone at the sixth week ( P<0.05 ) and Huang Qi improved systolic and diastolic function ( P<0.05 ).Compared with sham group,both collagen content (hydroxyproline levels) and the ratio of type Ⅰ/Ⅲ collagen of noninfarcted area (including infarct border) increased in AMI2 and AMI6 group ( P<0.05 ).The hydroxyproline levels and the ratio of type Ⅰ/Ⅲ collagen significantly decreased after Huang Qi and/or captopril treatment compared with AMI group at the second or the sixth week( P <0.05).CONCLUSION:Huang Qi can improve cardiac function after myocardial infarction and has beneficial effect on left ventricular collagen remodeling.