[The protective effect of captopril during myocardial ischemia and reperfusion and its mechanism].

OBJECTIVE

To investigate the myocardial protective effect of captopril (Cpl) during ischemia and reperfusion injury.

METHODS

Sixteen mongrel dogs were randomly divided into the control and Cpl groups. In the control group, only modified St. Thomas cardioplegia was used. In the Cpl group, St. Thomas cardioplegia and reperfusional blood containing captopril 4.6 mumol/L were used. The plasma renin activity (RA), contents of angiotensin II (AT-II) and endothelin-1 (ET-1) in arterial blood were determined before cardiopulmonary bypass (CPB) and 5, 35, 60 min after reperfusion. The myocardial RA, contents of AT-II, ET-1 and malondyldialdehyde (MDA) were also measured. Parameters of cardiac function were monitored simultaneously.

RESULTS

In the control group the plasma RA, AT-II and ET-1 contents were increased after reperfusion and significantly higher than those before CPB (P < 0.01). However, the content of AT-II in the Cpl group was not increased after reperfusion. The content of ET-1 in the Cpl group was increased but significantly lower than that in the control group (P < 0.01). The myocardial AT-II, ET-1 and MDA contents in the Cpl group were significantly lower than those in the control group. The cardiac index (CI) and coronary blood flow (CBF) in the Cpl group regained normal after reperfusion at 35 min.

CONCLUSIONS

Cardioplegia and reperfusion blood containing 4.6 mumol/L captopril could ameliorate the cardiac performances by inhibiting myocardial and systemic RAS and decreasing the ET-1 production.