Résumé
ObjectiveTo investigate the effect of heart-regulating and mind-calming acupuncture on the expression of gap junction protein connexin43 (Cx43) in myocardial cells in a rabbit model of ventricular arrhythmia.MethodA rabbit model of ventricular arrhythmia was made by injecting barium chloride into the marginal ear vein. Forty New Zealand rabbits were randomized into control, model, acupuncture and medication groups. The acupuncture group received heart-regulating and mind-calming acupuncture[at Lingtai(GV10), Shendao(GV11), bilateral Neiguan(PC6)and Baihui(GV20)]and the medication group, oral gavage of propafenone. Rabbit left ventricle was taken after the completion of the experiment. Cx43 expressions were compared and analyzed usingan immunohistochemical staining technique and a computer image processing system.ResultCx43 expression decreased significantly in the model group compared with the control group (P0.05).Conclusion Adjusting Cx43 expression in myocardial cells may be one of the target points for this acupuncture treatment of arrhythmia.
Résumé
Objective To determine whether specific angiotensin-conventing enzyme inhibitor with ramipril would affect ventricular arrhythmia generation in rabbits after myocardial infarction and discuss the mechanism of its antiarrhymic efficacy.MethodsTwenty-four New Zealand rabbits (Wuhan Laboratory Animal Research Center) were separated into 3 groups:sham-operated (SHAM) group (n =8 ),myocardial infraction (MI) group ( n =8) and myocardial infraction with ramipril (RAM) group ( n =8).SHAM group received a median sternotomy without left ventricular coronary artery ligation.MI and RAM groups' rabbits received a median sternotomy followed by left coronary artery ligation. The successful anterior MI was confirmed by elevation of the ST segment with more than 0.2 mV in lead Ⅱ and Ⅲ.After MI,RAM group rabbits were fed with ramipril [ 1mg/ ( kg · d) ]by intragastric administration for 12 weeks.Before and after MI 12 weeks in three groups.Ventricular tachycardia or fibrillation episodes and the monophasic actionpotential duration in epicardium,mid-myocardium and endocardium cadiocytes were recorded.The statistical technique was t-test and ANOVA.Results Ventricular tachycardia or fibrillation episodes were markedly decreased in RAM group than that in MI group after 12 weeks [ (2.6 ± 0.8) vs.(12.4 ± 2.9),P ＜0.05 ].After MI 12 weeks,the action potential duration of repolarization 90％ (APD90) of three-tier ventricular myocytes in MI group was prolonged than that before MI [ (258.2 ±21.1 ) vs.(230.1 ±23.2),( 278.0±23.8 ) vs.(245.8±25.4),(242.6±22.7) vs.(227.0±21.7),P＜0.05]; however,it was not significant difference between before and after MI 12w in RAM group (P ＞ 0.05 ).Moreover,the transmural dispersion of repolarization(TDR) was markedly increased after MI 12w in MI group than in SHAM and RAM group [ (36.2 ± 10.2 ) vs.( 18.7 ± 6.2 ),(24.9 ± 8.7 ),P ＜ 0.05 ]; but the TDR was not significant difference between RAM and SHAM group ( 18.7 ± 6.2 ) vs.( 24.9 ± 8.7 ),P ＞ 0.05].ConclusionsRamipril significantly reduced the malignant arrhythmia incidence in rabbits after MI.Mended the abnormal TDR was the mechanism for ramipril to therapy.