摘要OBJECTIVE:To observe the effects of electroacupuncture at Neiguan(PC6)at different time points on reperfusion arrhythmia(RA)after myocardial ischemia and reperfusion in rats,and to investigate the correlation of this protective effect with nerve growth factor(NGF),tyrosine kinase A(TrkA),tyrosine hydroxylase(TH),and norepinephrine(NE).METHODS:A total of 72 Sprague-Dawley male rats were randomly divided into six groups(n=12 rats/group):normal group(Norm),sham operation group(Sham),ischemia reperfusion group(I/R),pre-ischemic electroacupuncture group(EAⅠ),pre-reperfusion electroacupuncture group(EAⅡ),post-reperfusion electroacupuncture group(EAⅢ).The myocardial ischemia-reperfusion injury(MIRI)model was induced by occlusion of left anterior descending coronary artery for 20 min followed by reperfusion for 40 min in rats.With no intervention in the Norm group and only threading without ligation in the Sham group.Electroacupuncture pre-treatment at 20 min/d for 7 d before ligation in the EAⅠgroup,20 min of electroacupuncture before reperfusion in the EAⅡ group and 20 min of electroacupuncture after reperfusion in the EAⅢ group.The electrocardiogram(ECG)of each group was recorded throughout the whole process,and the success of the MIRI model was determined based on the changs of J-point and T-wave in the ECG.The arrhythmia score was used to record premature ventricular contractions,ventricular tachycardia and ventricular fibrillation during the reperfusion period to assess the reperfusion induced arrhythmias.The expression levels of NGF,TrkA,TH protein were measured by Western blot.Moreover,the expression levels of plasma and myocardial NE levels were detected by enzyme linked immunosorbent assay.RESULTS:The differences between Norm group and Sham group were not statistically significant in all indexes.Arrhythmia score,myocardial NGF,TrkA,TH,and NE expression were significantly higher in the I/R group compared with the Sham group.Arrhythmia score,myocardial NGF,TrkA,TH,and NE expression were significantly lower in each EA group compared with the l/R group.CONCLUSION:Electroacupuncture at Neiguan(PC6)at different time points can reduce the incidence and severity of reperfusion arrhythmias in rats.This protective effect is related to electroacupuncture regulating NGF,TrkA,TH,NE expression and reducing sympathetic hyperactivation.