The Effect Of Zandan-3 Decoction On Action Potential And Nav1.5,Kv4,3,hERG Current In Rat Cardiomyocytes

Objective:Previous studies have shown that Zandan-3 decoction can prolong the QRS interval of the heart and reduce arrhythmia caused by myocardial ischemia-reperfusion.This experiment used whole cell patch clamp technology to study the effect of Zandan-3 decoction on action potential and Nav1.5,Kv4.3,hERG current of acutely isolated rat ventricular myocytes,so as to provide experimental basis for clinical application.Method:(1)Take 10 adult male SD rats and acutely isolate ventricular myocytes;CHO cells stably expressing Nav1.5 channel protein,HEK 293 cells stably transfected with Kv4.3 and hERG channels.(2)Divide the cells into four groups:normal group,low dose group(1.25mg/ml)given Zandan-3 decoction,medium dose group(6.25mg/ml),and high dose group(12.5mg/ml).(3)Current clamp technique was used to record the action potential(AP)of ventricular myocytes and the effect of Zandan-3 decoction on AP in low dose group(1.25 mg/ml),medium dose group(6.25 mg/ml)and high dose group(12.5 mg/ml).(4)Voltage clamp was used to record the current of Nav1.5,Kv4.3,hERG channel and the influence of low dose group(1.25 mg/ml),medium dose group(6.25 mg/ml)and high dose group(12.5 mg/ml)of Zandan-3 decoction on ion channel.Result:(1)Zandan-3 decoction can prolong APD30,APD50,and APD90 of ventricular myocytes in a dose-dependent manner(n=10,p<0.05),affecting the ventricular repolarization process and leading to prolonged ERP;There was no significant effect on resting membrane potential of ventricular myocytes,in addition,there was no significant change in action potential amplitude.(2)Compared with the normal group,the low dose group(1.25mg/ml),medium dose group(6.25mg/ml),and high dose group(12.5mg/ml)of Zandan-3 decoction can shift the activation curve of Nav1.5 to the left,but have no significant effect on inactivation and recovery.(3)The study on HEK 293 cells with stable Kv4.3 channel has a certain inhibitory effect(n=4,p<0.05),but has no effect on activation kinetics,with varying degrees of left shift in inactivation;(4)Zandan-3 decoction significantly inhibited hERG current(n=4,p<0.05),causing the activation curve to shift to the left.Conclusion:(1)After the action of Zandan-3 decoction,the APD of rat ventricular muscle was significantly prolonged.The detection of ion channel current shows that Zandan-3 decoction has a certain inhibitory effect on Kv4.3,but has no effect on the activation kinetics,with varying degrees of deactivation.It also significantly inhibits hERG current,causing the activation curve to shift to the left.This indicates that Zandan-3 Wei Tang is an inhibitor of the K channel,leading to prolonged myocardial APD.(2)Zandan-3 decoction reduces arrhythmia caused by myocardial ischemia-reperfusion,which may be closely related to its dose-dependent prolongation of APD30,APD50,APD90 in ventricular myocytes and inhibition of Kv4.3 and hERG currents.