| Background Atrial fibrillation is one of the most common arrhythmia in clinic.The prevalence of AF is about 2%,which is increasing by years.With the increase of age,the number of people over 80 years old can be up to 9%.In clinical,the atrial fibrillation have serious harm,and the mortality and the rate of disability can not be ignored.It will increases the risk of ischemic stroke by 4-6 times and ventricular arrhythmia and the total mortality and lead to the decrease of cardiac function and sinoatrial node and atrioventricular node function.It has become a serious public health problem which seriously endangers human health.Therefore,it has become an urgent problem to explore the occurrence and maintenance mechanism of atrial fibrillation and to seek new therapeutic targets.1978,Coumel pointed out that autonomic nerve plays a role in the occurrence and development of AF.Exploring the etiology of AF in cardiac innervation and autonomic nervous system is the research focus of atrial fibrillation etiology in recent years.It is found that Wenxin Keli can regulate the function of autonomic nerve and reduce the excitability of sympathetic nerve,but the specific mechanism and effect characteristics are not clear yet.Objective In this study,we used acetylcholine(Ach)and epinephrine(ISO)to mediate acute atrial fibrillation(AF)from the level of isolated heart.Ach simulated as the role of vagus in atrial fibrillation.ISO simulated as the role of sympathetic nerve in atrial fibrillation,and observed the therapeutic effect of Wenxin Keli on it.The expression of sodium and calcium pathway related proteins was detected by molecular biology technique,and the effect of Wenxin Granule on cardiac electrical conduction was investigated by using the mapping technique.Method 1.Study on the effect and mechanism of Wenxin Keli on drug-induced atrial arrhythmia.The isolated hearts of female New Zealand rabbits were perfused by Langendorff.They were divided into Wenxin Keli group,ISO group,ISO+Wenxin granule group,Ach group and Ach+Wenxin granule group.In Wenxin Keli group,different concentrations of Wenxin Keli were perfused in normal hearts.ISO group and Ach group were treated with low concentration of isoproterenol(ISO or 15nM)or acetylcholine(Ach,luM)to induce atrial fibrillation.Before and after administration,atrial programmed stimulation(S1S2 stimulation and fixed pacing circumference of 300ms)induced polymorphic atrial tachycardia and atrial fibrillation.Simultaneously,right atrial phase action potential(MAP)and simulated 12 lead electroc ardiogram were recorded.The parameters of atrial fibrillation load,atrial fibrillation induced window and atrial effective refractory period were measured.After collecting the isolated heart,the content of CaMKII and Nav1.5 protein was detected by Western Blot method.2.The influence of the heart particles on the cardiac electrical conduction by the overall heart 64 channel mapping system.In the whole heart of the female New Zealand rabbit Langendorff,the 64 channel mapping system was used to place the two electrodes in the left and right atrium or the left and right ventricular outer membranes.A fixed frequency(4HZ)was used to stimulate the proximal sinoatrial node of the right auricle,or the ventricular apex of the left ventricle was paced at the apex of the left ventricle after the ablation of 1HZ.After the electrode was fixed,the conduction time,the average excitation time and the conduction sequence of the left and right atrium or left and right ventricles were recorded synchronously.After the concentration gradient was given to Wenxin granule,the changes of atrial and ventricular conduction time,average excitation time and conduction sequence were analyzed.Result 1.Study on the effect and mechanism of Wenxin Keli on drug-induced atrial fibrillation.The effective refractory period(aERP)was significantly prolonged in the isolated heart.At a fixed frequency 3HZ,ISO(15nM)sensitized heart can reduce the effective refractory period,S1S2 programmed electrical stimulation and acute atrial fibrillation was induced,atrial load(21±3)and atrial window(48±3);Wenxin Keli can concentrationdependent prolonged atrial window(17.6±4.9,19.3±5.1,17±5.8,7.6±3,8.3±1.9),and effective refractory period was gradually extended(n=6,p<0.01).When the concentration of Wenxin Keli reached 10g/L,it could completely inhibit AF.The stable heart granule can reduce the atrial fibrillation load and the atrial fibrillation window in a concentration dependent manner,and the effective refractory period is gradually extended(n=6,p<0.01).Under the 3HZ fixed frequency pacing,the normal ERP of the heart was(74.1±2.3).The isolated heart was treated with Ach(1uM),and irregular atrial fibrillation could be induced by S1S2 programmed electrical stimulation.The concentration gradient given Ach(0.01,0.03,0.1,0.3,1,3,5,10),a concentration dependent decrease in cardiac ERP(74±3.5,70±2.5,66.7±1.8,56±2.2,54±0.4,52.7±2,52±2.4),increasing atrial load(0+0,0+0,0.06+0.15,0.2+0.28,2.5+0.35,2.8+0.25,2.97+0.14)and increased AF window(0+0,0+0,0.2+0.39,0.3+0.89,3.5+1,5+0.9,5.6+1.3,6.1+1.03),Ach 1uM can produce AF.Molecular biology research shows that Wenxin Keli can reduce the calcium channel protein(Camk-II,PKC,SERCA)expression.2.The influence of the heart particles on the cardiac electrical conduction by the overall heart 64 channel mapping system.In normal heart,in order to atrial conduction from the sinoatrial node position of right atrial to left and right atrial conduction down,fixed frequency after pacing,right atrial to left atrial conduction time was(27.32±1.26)ms,right atrial conduction time was(14.36±1.47)ms,left atrial conduction time(13.68±1.59)ms,the conduction time of concentration gradient and left atrial conduction time given Wenxin Granule after right atrial and right atrial conduction time to the left atrium were gradually extended,extended to arrive at the concentration of 10g/L(80.38±3.25,40.02±2.48,29.42±2.33)ms,3g/L has statistics the difference(n=8 p<0.05);at the same time,AF time and left and right atrial activation time was gradually increasing(p<0.05),with the increase of Wenxin Keli concentration,atrial activation pattern did not change.ISO(15nM)prolongs only the conduction time and the average exciting time of the left atrium,and the conduction time of the right atrium to the left atrium has no change in the whole.Ach(1uM)significantly shortened atrial conduction time and average activation time,and WXKL 5g/L significantly prolonged atrial conduction time and atrial mean activation time.Conclusion 1.Wenxin Keli increase the effective refractory period and the action potential time of the isolated heart.Wenxin Keli can inhibit AF that induced by Ach and ISO,and reduce the incidence of AF,AF burden and AF window.The expression may be related to the inhibition of calcium channel protein that inhibits the process of the occurrence of AF and has no proarrhythmic effects.2.in the fixed frequency stimulation,conduction time of Wenxin Keli can significantly extend to the right atrial and left atrial conduction time and average activation time,left and right atrial and average activation time,3g/L had significant difference,ISO has no effect on the atrial conduction time,Ach can obviously shorten the conduction time of AF.Wenxin Keli can concentration dependent atrial conduction time and average activation time,Wenxin Granule inhibiting arrhythmia may be related to prolonged atrial electrical conduction time and average activation time,real and Wenxin Granule selective effect.3.Wenxin granule can inhibit atrial fibrillation mediated by autonomic nerve. |
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