Ghrelin对大鼠离体心脏缺血再灌注损伤的保护作用

目的　研究促生长激素释放肽ghrelin对大鼠心脏缺血 /再灌注 (ischemia/reperfusion ,I/R)损伤的直接保护作用。方法　在大鼠离体心脏I/R模型上 ,观察ghrelin对大鼠离体心脏血流动力学和代谢改变的影响 ,及大鼠缺血和I/R损伤时心肌肌浆膜ghrelin受体变化。结果　ghrelin灌流显著减轻大鼠I/R损伤时的心功能紊乱 ,减少心肌乳酸脱氢酶及肌红蛋白漏出 ,抑制心肌脂质过氧化物生成 ,增加心肌ATP含量 ;受体结合实验表明 ,在大鼠心脏缺血及I/R损伤时 ,心肌肌浆膜ghrelin受体的结合位点增加 ,但亲和力无明显改变。结论　ghrelin对心脏I/R损伤具有非生长激素释放依赖的直接保护作用

Protective effects of ghrelin on ischemic/reperfusion injury of isolated hearts in rats

AIM To investigate the direct cardioprotective effects of ghrelin on ischemic/reperfusion injury of isolated hearts in rats. METHODS Using the ischemic/reperfusion (I/R) model of rat hearts, the effects of ghrelin on hemodynamics of isolated rat hearts were observed, and the ghrelin receptor binding sites in sarcoplasm membrane of ischemic and I/R hearts were also tested. RESULTS Ghrelin obviously improved the disturbance of hemodynamics and metabolism of I/R injury in isolated rat hearts,which showed as increased cardiac contraction ability, decreased LDH, Mb leakage out from rat hearts, and decreased myocardiac MDA generation and increased ATP content. The receptor binding site test showed that the ghrelin receptor binding sites were increased in ischemic and I/R injury hearts in rats, whereas the affinity of ghrelin to ghrelin receptor in heart sarcoplasm membrane has no obviously change. CONCLUSIONS Ghrelin exerts directly protective effects on ischemic/reperfusion injury of isolated heart in rats in a growth hormone-independent manner.