不同时间电针“内关”预处理对心肌缺血再灌注大鼠心功能、胰岛素抵抗的影响及机制研究

Effect and Mechanism of Different Preconditioning Time of Electro-Needling PC6 on Cardiac Function and Insulin Resistance in Rats with MIRI

目的:探讨电针“内关”预处理对心肌缺血再灌注大鼠的心功能指标及胰岛素抵抗水平的变化,探讨其保护作用及时间规律。方法:本实验采用SPF级Wistar雄性大鼠60只,随机分为对照组、模型组、电针预处理0.5 h组、电针预处理1 h组、电针预处理2 h组与电针预处理3 h组,每组各10只。对照组开胸后仅暴露心脏不做其它处理;模型组采用左前降支冠状动脉结扎术,缺血20 min,再灌注40 min,制备心肌缺血再灌注损伤模型;其他电针预处理组分别于造模前0.5~3 h选取大鼠双侧“内关”穴进行电针,造模方法同模型组。观察各组左心室功能指标,采用酶联免疫分析法检测大鼠血浆内β-内啡肽、胰岛素、C肽和抵抗素的含量,并在透射电镜下观察心肌组织的变化。结果:与对照组比较,模型组以及各电针预处理组的舒张末期压力、左室收缩期平均压、左心室内压最大上升速率和左心室内压最大下降速率差异有统计学意义(P<0.05)、电针预处理各组与模型组比较,LVEDP显著降低,LVSP、+dp/dtmax和-dp/dtmax水平有所上升(P<0.05)。与对照组比较,模型组以及各电针预处理组的β-内啡肽(β-EP)、胰岛素、C肽和抵抗素的含量升高明显(P<0.05);电针预处理各组与模型组比较,电针干预能显著下调β-EP、胰岛素、C肽和抵抗素的含量(P<0.05)。上述各项指标中,电针预处理2 h组和电针预处理3 h组优于电针预处理0.5 h组和电针预处理1 h组,电针预处理0.5 h组和电针预处理1 h组相比较各项指标差异无统计学意义(P>0.05),电针预处理2 h组和电针预处理3 h组比较各项指标差异无统计学意义(P>0.05)。病理结构方面,模型组较对照组大鼠心肌组织结构破坏显著,电针预处理组与模型组比较其心肌组织结构有所改善。结论:电针预处理能通过调控应激反应及胰岛素抵抗相关因子来降低心肌缺血对心功能的损害,且不同的预处理时间点对心肌组织的保护效应具有差异性。

Objective:To explore the protective effect and different preconditioning time of electro-needling Neiguan(PC6)in rats with myocardial ischemia-reperfusion injury(MIRI)in terms of cardiac function and insulin resistance.Methods:60 male SPF Wistar rats were randomly divided into the control group,the model group,the electro-acupuncture preconditioning groups(0.5 h group,1 h group,2 h group,3 h group),with 10 rats in each group.The rats in the control group were only exposed the heart after the thoracotomy without being given any other treatment.The MIRI models were established by artery ligation of anterior descending coronary(20 minutes of ischemia and 40 minutes of reperfusion).Preconditioning of electro-needling PC6 was conducted at 0.5~3 h before modelling.The left ventricular function indexes were observed,and the plasma contents ofβ-endorphin,insulin,C-peptide and resistin were measured by enzyme-linked immunoassay,and the changes of myocardial tissues were observed under transmission electron microscopy in each group.Results:Compared to those in the control group,LVEDP was significantly increased,and LVSP,+dp/dtmax and-dp/dtmax were significantly decreased in the model group and in the electro-acupuncture preconditioning groups(P<0.05);compared to those in the model group,LVEDP was significantly decreased,and LVSP,+dp/dtmax and-dp/dtmax were significant increased in the electro-acupuncture preconditioning groups(P<0.05).In terms of the contents ofβ-EP,insulin,C-peptide and resistin,they were significantly increased in the model group and in the electro-acupuncture preconditioning groups(P<0.05);compared to those in the model group,they were significantly reduced in the electro-acupuncture preconditioning groups(P<0.05);among the above indicators,the 2 h group and the 3 h group were better than the 0.5 h group and the 1 h group(P<0.05),there were no significant differences between the 0.5 h group and the 1 h group,as well as between the 2 h group and the 3 h group(P>0.05).In terms of pathologic changes of the myocardial tissues,they were significantly damaged in the model group compared to those in the control group;which could be improved by electro-acupuncture preconditioning.Conclusion:Electro-acupuncture preconditioning can reduce the damage of cardiac function by regulating stress response and insulin resistance-related factors in rats with MIRI,and the protective effects on myocardial tissue are different at different preconditioning time points.