The effects of nitric oxide on the cardiac function of ischemic and reperfused myocardium of rats in vivo / 中华胸心血管外科杂志

ABSTRACT

Objective To determine whether nitric oxide may result in different effects on cardiac function at the different time points during the course of myocardial ischhemia and reperfusien of rats in viwo, and if so, to investigate the mechanisms involved.Methods Male adult rats were subjected to 30 minutes of myocardial ischemia followed by 5 hours of reperfusien. L-arginine was administrated at a bolus at both 10 minutes before and 50 minutes after reperfusion in early treatment group. The L-arginine was administrated at a bolus at both 3 and 4 hours after reperfusion in late treatment group. The following variables were measured cardiac hemodynamic parameters, myocardial easpase 3 activity, iNOS and total NO content. Results Compared with vehicle group, administration of L-arginine at early reperfusion markedly reduced myocardial caspase 3 activity, and improved cardiac function. In strict contrast, administration of L-arginine at late reperfusion resulted in a significant increase in myocardial NOx content, myocardial apoptosis, and depressed the cadiac function. Conclusion Timely administration of L-arginine might inhibit apoptosis while late administration of L-arginine might enhance apoptosis.