褪黑素对鼠心肌缺血再灌注损伤的保护作用

Protective effects of melatonin on isolated rat myocardium after ischemic-reperfusion

目的探讨不同浓度褪黑素预处理对成年大鼠心肌缺血再灌注损伤的影响。方法32只成年SD大鼠(350～400g)随机分为4组(n=8),利用Langendorff模型灌注其离体心脏,对照组平衡30min后缺血再灌注,实验组用不同浓度褪黑素预处理液灌注30min后缺血再灌注。各组均为常温(37℃)缺血25min,复灌60min。观察各组冠脉流出液中心肌肌钙蛋白(cTnI)、心肌超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量及心肌细胞超微结构的变化。结果复灌后,cTnI含量(μg/L)Ⅰ组为2.69±0.18,Ⅱ组为1.75±0.13,Ⅲ组为1.06±0.08,Ⅳ组为0.45±0.11;心肌组织SOD(nu/mg蛋白)和MDA(nmol/mg蛋白)含量Ⅰ组为207.4±7.9和1.815±0.018,Ⅱ组为238.3±2.9和1.472±0.518,Ⅲ组为268.3±5.7和1.122±0.263,Ⅳ组为315.6±9.0和0.961±0.223。心肌细胞电镜观察显示预处理组心肌细胞损伤轻于对照组。结论褪黑素预处理对成年大鼠缺血再灌注心肌有保护作用。

Objective To investigate the protective effects of Melatonin on myocardial ischemia/reperfusion injury in isolated Sprague-Dawley rat myocardium.Methods Thirty-two adult Sprague-Dawley rats (350-400 g) were randomly divided into 4 groups.Hearts were subjected to 25 min of normothermic global ischemia followed by 60 min of reperfusion.Results cTnI and MDA levels were the lowest in 100μmol/L melatonin pretreatment group,and melatonin groups also had a higher level of tissue SOD.Conclusion Melatonin is an effective agent for protection against postischemic reperfusion injury.