Effects Of Electroacupuncture At "Neiguan Point" On Ventricular Myoelectric Conduction And Connexin 43 After Ischemia-reperfusion In Rats

Objective:We established a model of myocardial ischemia/reperfusion injury in rats,and observed the effects of electroacupuncture at "Neiguan acupuncture point" on myocardial electrical conduction and expression of connexin 43 in rats with ischemia/reperfusion.The study was conducted to investigate the specific mechanism of reperfusion arrhythmias alleviated by electroacupuncture at "Neiguan point",so as to provide theoretical basis for clinical prevention and treatment of reperfusion arrhythmias.Methods:A total of twenty-four adult male Sprague Dawley(SD)rats were randomly assigned into sham operation group(SH group),ischemia reperfusion group(I/R group)and electroacupuncture group(EA group),three groups with 8 in each group.The model of myocardial ischemia-reperfusion injury was established by ligating the left anterior descending coronary artery(LAD)for 30 min and reperfusion for 30 min in rat.The myocardial ischemia reperfusion model was established in I/R and EA groups,and Neiguan point was needled after the EA model was successfully established.Heart rate(HR)and mean arterial blood pressure(MAP)before coronary artery ligation(T0),ischemia for 30min(T1)and reperfusion for 30min(T2)were recorded,and the arrhythmias during reperfusion were recorded.The DF-5A cardiac stimulator was used for stroke controlled stimulation at 30 min of reperfusion,and the conduction velocity(CV),effective refractory period(ERP)and the ventricular fibrillation threshold(VFT)were measured,the excitation wavelength(λ)was calculated.The expression of Cx43 was detected by Western-blotting.The distribution of Cx43 protein was detected by immunohistochemistry.Results:Compared with SH group,the HR of EA group and I/R group at T1-T2 decreased(P<0.05).Compared with I/R group,the HR in EA group increased at T2(P<0.05).Compared with T0,the HR of I/R group and EA group decreased at T1-T2(P<0.05).Compared with T1,the HR of I/R group and EA group increased at T2(P<0.05).Compared with SH group,the MAP of I/R group and EA group decreased at T1-T2(P<0.05).Compared with I/R group,the MAP of EA group increased at T2(P<0.05).Compared with T0,the MAP of I/R group and EA group decreased at T1-T2(P<0.05).Compared with T1,the MAP of EA group increased at T2(P<0.05).Compared with SH group,the CV,ERP and λ were decreased in I/R group and EA group(P<0.05).Compared with I/R group,the CV,ERP and λ were increased in EA group(P<0.05).Compared with SH group,the expression of Cx43 was decreased in I/R group and EA group(P<0.05).Compared with I/R group,the expression of Cx43 was increased in EA group(P<0.05).Immunohistochemical staining showed that Cx43 positive staining was brownish yellow and distributed in cell membrane and cytoplasm.Compared with SH group,the arrhythmia score and incidence of arrhythmia were increased in I/R and EA group(P<0.05).Compared with I/R group,the arrhythmia score and incidence of arrhythmia were decreased in EA group(P<0.05).There was no significant difference of VFT in SH group,I/R group and EA group(P>0.05).Conclusions:Electroacupuncture at "Neiguan point" could reduce the occurrence of reperfusion arrhythmia by improving the electrical conduction dysfunction of ischemia-reperfusion ventricular muscle and upregulating the expression of Cx43.