针刺“内关”预处理对大鼠缺血再灌注心肌的保护作用及机制研究

Electroacupuncture Preconditioning at “Neiguan” Prevents Myocardial Ischemia-reperfusion Injury in Rats by Activating p38-MAPK Pathway

目的探讨电针"内关"预处理是否通过p38 MAPK信号通路来影响心肌缺血再灌注损伤。方法选用3月龄Wistar雄性大鼠40只,体重(220±23)g,编号后按随机数字表分入对照组(仅穿线,不结扎)、模型组、电针预处理组、电针预处理+SB230580组,每组10只。通过阻断左冠状动脉前降支缺血30min,再灌注120min,检测心肌缺血再灌注损伤后各项心功能指标(舒张末期压力、左室收缩期平均压、短轴缩短率和射血分数),检测心肌组织中活性氧(ROS)含量,超氧化物歧化酶SOD活性,丙二醛(MDA)含量及ATP含量,透射电镜下观察心肌超微结构的变化。结果与对照组比较,模型组各项心功能指标中舒张末期压力升高,左室收缩期平均压、短轴缩短率和射血分数均降低(均P<0.05),梗死面积和梗死程度均升高(均P<0.01),心肌肌纤维溶解、断裂,间质增大,心肌细胞肿胀明显,SOD活性及ATP含量明显下降,ROS及MDA含量明显上升(均P<0.05),电针预处理可明显减轻这种变化,差异具有统计学意义(均P<0.05),SB230580抑制剂可减弱电针"内关"预处理的这种作用(均P<0.05)。结论电针"内关"预处理能显著改善心肌缺血再灌注损伤后心功能及心肌细胞活性,降低心肌梗死面积,减轻线粒体的肿胀程度,保护线粒体的完整性。这种保护作用可能与改善心肌细胞的呼吸功能有关。

Objective To investigate the protective mechanism of electroacupuncture preconditioning at ＂Neiguan＂ in preventing myocardial ischemia-reperfusion injury（MIRI）in rats.Methods Forty male Wistar rats,3 months old,weighting about（220±23）g,were randomly divided into four groups：sham operation group（sham group）,MIRI model group（model group）,electroacupuncture preconditioning group（EA group）and electroacupuncture preconditioning＋SB203580 group（EA ＋SB group）,with 10 rats in each group.The MIRI model was achieved by the ligation of the left anterior descending artery to cause ischemia for 30 min and then deligation for 120-min reperfusion.Before the model establishment,rats in the EA group and EA＋SB group received electric acupuncture for 20min（1mA,continuous wave）.After MIRI,the cardiac function indexes including left ventricular end-diastolic pressure（LVEDP）,left ventricular systolic mean pressure（LVSP）,fractional shortening（FS）and ejection fraction（EF）were evaluated.Myocardial tissues were later obtained,the contents of ROS,SOD,MDA and ATP were detected and the ultrastructures were observed.Results Rats in the model group had increased infarction size when compared with those in the sham group.Their LVSP,FS and EF were much lower,and LVEDP much higher than those in the sham group（P0.05）.There were dissolved and necrotic muscle fibers,increased myocardial interstitial gap and edema in the model group.The contents of ROS and MDA were increased,and those of ATP and SOD activity decreased in the model group as compared with those in the sham group（P0.05）.These indexes were greatly improved in rats experiencing electroacupuncture preconditioning,whereas the effects were suppressed after addition of SB230580（P0.05）.Conclusion Electroacupuncture preconditioning at＂Neiguan＂significantly improves the cardiac function,increases the cell activity,decreases the infarction area,mitigates the mitochondrial swelling and protects the integrity of the mitochondria,which may be associated with the improvement of the respiratory function of myocardiocytes.