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

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。

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

AIM:To observe the effects of shortterm 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 Ⅱ lead 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 Ca~(2+)/Mg~(2+)-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~+-AT-Pase,Na~+/K~+-ATPase,Ca~(2+)/Mg~(2+)-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.