褪黑素对缺血再灌注心律失常的作用

目的:探讨外源性褪黑素(M LT)对在体大鼠心脏缺血再灌注心律失常的作用。方法:34只大鼠随机分为对照组、缺血再灌注(I/R)组及缺血再灌注 褪黑素(I/R M LT)组,I/R组及I/R M LT组在体大鼠心脏左冠状动脉前降支完全阻断10 m in,再灌15 m in,监测记录室性心动过速、室颤的发生情况,并测定局部再灌注心肌中M DA(丙二醛)的含量和SOD(超氧化物歧化酶)的活性。结果:室性心动过速、室颤的发生率I/R M LT组明显低于I/R组(P<0.05);I/R组M DA的含量明显高于对照组及I/R M LT组(P<0.01),SOD活性明显低于对照组及I/R M LT组(P<0.01),I/R M LT组M DA含量及SOD活性与对照组无明显差异(P>0.05)。结论:褪黑素可抑制在体大鼠心脏缺血再灌注心律失常的发生,其作用机制可能与其作为自由基清除剂抗氧化作用有关。

Effects of melatonin on acute ischemia-reperfusion induced arrhythmias in rats in vivo

Objective:To investigate the effects of MLT(melatonin) on acute ischemia-reperfusion induced arrhythmias in rats in vivo.Methods:A total of 36 anesthetized rats were separated randomly into 3 groups: 1) control group(n=12),without LAD(left anterior descending coronary artery) ligation and MLT;2) I/R(ischemia reperfusion) group(n=12),LAD was ligated for 10 min and reperfused for 15 min without MLT;3) I/R MLT group(n=12),MLT(10 mg/kg) was injected via peritonium 10 min before LAD ligation.ECG was continuously monitored and recorded throughout the whole process,MDA(malondialdehyde,lipid peroxidation product,an index of myocardium damage) and SOD(superoxide dismutase) activity were tested in the injured myocardium.Results:The incidences of ventricular tachycardia and ventricular fibrillation during reperfusion were significantly lower in I/R MLT group than those in I/R group(P<0.05).The levels of MDA were significantly higher while the SOD activities were lower in I/R group compared to I/R MLT and control group(P<0.01),but there isn't significant difference between I/R MLT and control group(P>0.05).Conclusion:These results suggest that melatonin can significantly inhibit ischemia/reperfusion induced ventricular arrhythmias in rats in vivo.Its mechanism may be the MLT related to role of anti-oxydation.