Objectives To investigate the influences of bradykinin （BK） on hemodynamics, left ventricular hypertrophy and interstitial collagen metabolism after myocardial infarction （MI） in rats and the contribution of BK in...Objectives To investigate the influences of bradykinin （BK） on hemodynamics, left ventricular hypertrophy and interstitial collagen metabolism after myocardial infarction （MI） in rats and the contribution of BK in angiotensin-converting enzyme （ACE） inhibition therapy. Methods By means of hemodynamic measurements, morphometric study of myocyte hypertrophy and SDS-PAGE technique, the effects of enalapril （500 μg.kg^-1.day^-1 ）, enalapril （500 μg.kg^-1.day^-1） with BK B2 receptor antagonist Hoe-140 （500 μg . kg^-1.day^-1）, angiotensin Ⅱ （AgⅡ） type 1 （AT1） receptor antagonist losartan （3 mg.kg^-1.day^-1 ） on mean arterial pressure （MAP）, left ventricular end-diastolic pressure （LVEDP）, as well as maximum positive left ventricular pressure change （ ＋ dp/dtmax）, V（m） n, collagen content and the ratio of type Ⅰ to type Ⅲ collagen （ Ⅰ / Ⅲ ） of noninfarcted area were observed in rats after MI. Treatments were started on the 3rd day after MI and continued for another 28 days. Results Enalapril reduced LV- EDP, V （m） n and collagen content as well as collagen Ⅰ /Ⅲ compared with the untreated MI group （ P 〈 0. 05 ）, and all of these effects of enalapril were partly blunted by concomitant treatment with hoe-140 （ P 〈 0. 05 ）. Losartan was less effective than enalapril （P 〈 0. 05 ）. However, three treatment groups had no significant differences in ＋ dp/dtmax and had similar reductions in MAP compared with untreated MI group. Conclusions BK can improve cardiac function and prevent left ventricular hypertrophy with myocardial fibrosis independent of blood pressure. The mechanisms of ACEI are both blockade of Ang Ⅱ formation and inhibition of BK degradation.展开更多
文摘Objectives To investigate the influences of bradykinin （BK） on hemodynamics, left ventricular hypertrophy and interstitial collagen metabolism after myocardial infarction （MI） in rats and the contribution of BK in angiotensin-converting enzyme （ACE） inhibition therapy. Methods By means of hemodynamic measurements, morphometric study of myocyte hypertrophy and SDS-PAGE technique, the effects of enalapril （500 μg.kg^-1.day^-1 ）, enalapril （500 μg.kg^-1.day^-1） with BK B2 receptor antagonist Hoe-140 （500 μg . kg^-1.day^-1）, angiotensin Ⅱ （AgⅡ） type 1 （AT1） receptor antagonist losartan （3 mg.kg^-1.day^-1 ） on mean arterial pressure （MAP）, left ventricular end-diastolic pressure （LVEDP）, as well as maximum positive left ventricular pressure change （ ＋ dp/dtmax）, V（m） n, collagen content and the ratio of type Ⅰ to type Ⅲ collagen （ Ⅰ / Ⅲ ） of noninfarcted area were observed in rats after MI. Treatments were started on the 3rd day after MI and continued for another 28 days. Results Enalapril reduced LV- EDP, V （m） n and collagen content as well as collagen Ⅰ /Ⅲ compared with the untreated MI group （ P 〈 0. 05 ）, and all of these effects of enalapril were partly blunted by concomitant treatment with hoe-140 （ P 〈 0. 05 ）. Losartan was less effective than enalapril （P 〈 0. 05 ）. However, three treatment groups had no significant differences in ＋ dp/dtmax and had similar reductions in MAP compared with untreated MI group. Conclusions BK can improve cardiac function and prevent left ventricular hypertrophy with myocardial fibrosis independent of blood pressure. The mechanisms of ACEI are both blockade of Ang Ⅱ formation and inhibition of BK degradation.
