Effect And Mechanism Of Electroacupuncture At Neiguan On Ventricular Arrhythmia After Myocardial Infarction

Objective:To investigate the preventive and therapeutic effect of electroacupuncture at Neiguan on ventricular arrhythmia after myocardial infarction and its effect on sympathetic remodeling.Methods:Fourteen adult healthy beagle dogs were randomly divided into two groups:Electroacupuncture group(n=7):ligation of coronary artery,electroacupuncture stimulation of Neiguan point(continuous four weeks,stimulation 1times every other day,stimulation of 2 hours every time).Control group(n=7):ligation of coronary artery,acupuncture at Neiguan point,pseudo stimulation.The incidence of ventricular arrhythmia(VA),ventricular effective refractory period(VERP),left ventricular function and histopathological changes were compared between the two groups.The distribution of vagal and sympathetic nerve and the changes of protein xpression in the ventricular myocardium were measured.Results:(1)Two groups of dogs with myocardial infarction within 24 hours after infarction VA incidence increased significantly compared to the baseline values,the electroacupuncture group stimulation after 4 weeks of episodes of VA were significantly lower than the control group(P<0.05).(2)Electroacupuncture group showed a significant decrease in the number of sympathetic trunk[(3137±537)μm/mm~2 vs(13654±1160)μm/mm~2]in the left ventricle(4510±657μm/mm~2 vs 9674±1330μm/mm~2/(8745±778)μm/mm~2 vs(14350±1554)μm/mm~2],the density of tyrosine hydroxylase(TH)-positive nerve fibers was significantly decreased(P<0.05)(5891±598)μm/mm~2 vs(10257±1030)μm/mm~2,P<0.05),while the number of CHAT-positive nerve fibers in the electroacupuncture group was significantly lower than that in the control group[(7591±922)μm/mm~2 vs(654±120)μm/mm~2],and the density of nerve fibers positive for choline acetyltransferase(CHAT)was significantly increased in[(8745±752)μm/mm~2 vs(5341±365)μm/mm~2/P<0.05).The protein expressions of ADRB1,TrkA and P75NGFR in EA group were significantly lower than those in control group(P<0.05).Conclusion:Acupuncture at Neiguan can inhibit spontaneous ventricular arrhythmia after myocardial infarction,reduce the threshold of ventricular fibrillation,reverse and improve myocardial infarction caused by VERP shortening,dERP increased change.Acupuncture at Neiguan can improve cardiac autonomic nerve remodeling after infarction,reverse the state of sympathetic nerve activity after myocardial infarction,inhibit the sympathetic nerve regeneration after infarction,and improve the abnormal distribution of adrenoceptors.