L-精氨酸-NO途径在心肌缺血再灌注损伤中的作用

Role of L arginine Nitric Oxide Pathway in Myocardial Ischemia Reperfusion Injury

目的 观察大鼠心肌缺血前给予含不同浓度的L-精氨酸和L-NAME的KH灌注液的心肌保护作用。方法 在心肌缺血前给予含不同浓度的L-精氨酸和L-NAME的KH灌注液,再灌注期间测定心脏功能指标及冠脉流出液中心肌酶释放量,观察心肌超微结构改变。结果 心肌缺血前给予含低浓度L-精氨酸的KH液(10 m m ol/L)灌注心脏,能明显减轻心肌缺血再灌注损伤,心肌缺血前给予含高浓度L-精氨酸的KH 液(100 m m ol/L)灌注心脏明显加重心肌缺血再灌注损伤,而给予含L-NAME的KH液无明显心肌保护或损害作用。结论 L-arg-NO 途径在心肌缺血再灌注损伤中有双重作用,既有有益一面,又有有害一面。

Objective To evaluate the myocardial protective effects of L arginine (L arg) added to KH buffer before myocardial ischemia in isolated rat heart model undergoing both myocardial ischemia and reperfusion.Methods 40 SD rats were divided into four groups randomly, namely LA10group,LA100 group,L NAME group and control group.In the control group the isolated working rat hearts were perfused with KH buffer only,but in LA10 group,LA100 group and L NAME group, 10 mmol/L L arg, 100 mmol/L L arg and 1 mmol/L L NAME were added to KH buffer respectively for the last 10 minute perfusion before myocardial ischemia occurred.Then,90 minutes after myocardial ischemia, all rat hearts were subjected to 30 minute reperfusion with KH buffer.Cardiac function indices and outflow of LDH and CPK from reperfusion were tested during reperfusion.The ultra microscopic structure of myocardium was also observed.Results The percent recoveries of LVSP,±dp/dtmax and CF in group LA10 were significantly better than those in control group (P<0.01) during reperfusion (10 30 minutes).In LA10 group, the outflows of LDH and CPK were less than those in control group during early reperfusion (P<0.01).On the other hand, the study showed that the percent recoveries of left ventricular function, in terms of LVSP,±dp/dtmax and CF,were significantly worse in LA100 group than those in control group and outflows of LDH and CPK were more in LA100 group than those in control group during reperfusion (P<0.05).Conclusion These data suggest that administration of low dose L arginine before myocardial ischemia might ameliorate myocardial ischemia reperfusion injury on enhancing functional recovery of heart, reducing resistance of coronary vessels, and decreasing outflows of LDH and CPK while high dose L arginine added to KH buffer might aggregate reperfusion injury.