短期禁食对大鼠心肌缺血/再灌注心律失常及心肌能量代谢的影响

Effects of short-term fasting on energy metabolism and arrhythmia after myocardial ischemia/reperfusion in rats

目的:观察短期禁食(STF)对大鼠心肌缺血/再灌注(I/R)心律失常及心肌能量代谢的影响。方法:80只SD大鼠,随机分为对照组、I/R组、STF组、胺碘酮组、联合应用组。采用结扎冠状动脉左前降支30min,再灌注120min,建立心肌I/R模型。监测标准肢体Ⅱ导联心电图(ECG),记录缺血期间室性心律失常(VA)的发生情况。实验结束取心肌,提取线粒体,测定线粒体细胞色素氧化酶(COX)及H+-ATPase活性,采用HPLC法测定心肌组织中高能磷酸化合物ATP、ADP和AMP的含量,以试剂盒测定心肌组织Na+/K+-ATPase、Ca2+/Mg2+-ATPase活性,观察STF对心肌的保护作用,并与胺碘酮作比较。结果:与I/R组比较,STF组室性早搏(VPC)出现时间明显推迟(P<0.01),持续时间明显缩短(P<0.01),室性心动过速(VT)和心室纤颤(VF)发生率都明显降低(P<0.05);I/R组COX和H+-AT-Pase活性、心肌腺苷酸含量、ATPase的活性均显著降低(P<0.01),STF可使上述各种酶的活性及心肌腺苷酸的含量有所提高(P<0.01)。以STF与胺碘酮联合应用对心肌的保护作用最为显著。结论:STF具有抗大鼠心肌I/R心律失常的作用,其机制可能与改善心肌组织的能量代谢有关。

AIM：To observe the effects of short-term fasting （STF） on myocardial energy metabolism and arrhythmia after myocardial ischemia/reperfusion （I/R） in rats. METHODS：80 SD rats were randomly divided into 5 groups：normal control group,I/R group,STF group,amiodarone group,combination group （STF＋amiodarone）. The I/R model of SD rats was established by deligation left anterior descending coronary artery 30 min,reperfusion 120 min.The standard limbs Ⅱlead electrocardiogram （ECG）was monitered and the occurrence condition of ventricular arrhythmia （VA） was recorded. The activities of cytochrome-oxydase（COX） and H＋-ATPase were detected,after the myocardial mitochondria was extracted. The high energy phosphates （ATP,ADP and AMP） levels in myocardium were measured by HPLC. The activities of Na＋/K＋-ATPase and Ca2＋/Mg2＋-ATPase in myocardium tissues were determined. The protection was observed to myocardium,and the results were compared with the protection in amiodarone group. RESULTS：Compared with I/R group,the onset of ventricular premature contraction （VPC） was delayed markedly （P〈0.01）,the duration of VPC was shorted （P〈0.01）,the incidences of ventricular tachycardia （VT） and ventricular fibrillation （VF） were decreased （P〈0.05） in STF group. The activities of COX,H＋-ATPase,Na＋/K＋-ATPase,Ca2＋/Mg2＋-ATPase and the contents of myocardial adenine nucleotide were decreased signifcantly in I/R group. STF could increase the levels of COX,ATPase and myocardial adenine nucleotide contents （P〈0.01）. The myocardial protective effects of the combination group was the best. CONCLUSION：STF has antiarrhythmic effect in rats,the protective action is related to the improvement of energy metabolism.