葛根素通过调控NF-κB通路对大鼠心肌梗死后室性心律失常及体表心电图参数的影响

Effect of Puerarin on Ventricular Arrhythmia and Surface Electrocardiogram Parameters after Myocardial Infarction in Rats by Regulating NF-κB Pathway

目的:探讨葛根素对大鼠心肌梗死后室性心律失常(VA)和体表心电图参数的影响及其可能作用机制。方法:选取65只SD大鼠,结扎冠状动脉制备心肌梗死模型,造模成功后随机分为模型组、葛根素组、脂多糖(LPS)组、LPS+葛根素组,另取15只大鼠只剪开心包不结扎冠状动脉作为假手术组。葛根素组腹腔注射120 mg/kg葛根素,每日1次,连续7 d;LPS组腹腔注射0.5 mg/kg LPS 1次;LPS+葛根素组腹腔注射0.5 mg/kg LPS 1次后,再注射120 mg/kg葛根素,每日1次,连续7 d;假手术组和模型组实验期间给予腹腔注射等量生理盐水。程序电刺激室性期前收缩法诱发大鼠VA后检测有效不应期(ERP)、心室颤动阈值。肢体导联心电图机检测大鼠体表心电图。酶联免疫吸附实验(ELISA)法检测血清肿瘤坏死因子α(TNF-α)和白细胞介素1β(IL-1β)含量。2,3,5-氯化三苯基四氮唑(TTC)染色观察大鼠心肌梗死面积。蛋白免疫印迹(Western Blot)法检测心肌组织中核转录因子κB(NF-κB)通路相关蛋白表达水平。结果:与模型组比较,葛根素组VA诱发率、T波幅度、ST段抬高幅度、心肌梗死面积比例、血清TNF-α和IL-1β水平、p-p65相对表达量降低,ERP延长,心室颤动阈值、NF-κB抑制剂α(IκBα)相对表达量升高,心电图QT间期缩短,均P<0.05;LPS组VA诱发率、T波幅度、ST段抬高幅度、心肌梗死面积比例、血清TNF-α和IL-1β水平、p-p65相对表达量升高,ERP缩短,心室颤动阈值、IκBα相对表达量降低,心电图QT间期延长,均P<0.05。与葛根素组比较,LPS+葛根素组VA诱发率、T波幅度、ST段抬高幅度、心肌梗死面积比例、血清TNF-α和IL-1β水平、p-p65相对表达量升高,ERP缩短,心室颤动阈值、IκBα相对表达量降低,心电图QT间期延长,均P<0.05。与LPS组比较,LPS+葛根素组VA诱发率、T波幅度、ST段抬高幅度、心肌梗死面积比例、血清TNF-α和IL-1β水平、p-p65相对表达量降低,ERP延长,心室颤动阈值、IκBα相对表达量升高,心电图QT间期缩短,均P<0.05。结论:葛根素可以改善大鼠心肌梗死后VA,影响体表心电图参数,其作用机制可能与调控NF-κB通路有关。

Objective:To investigate the effects of puerarin on ventricular arrhythmia(VA)and surface electrocardiogram parameters after myocardial infarction(MI)in rats and its possible mechanism.Methods:Sixty-five SD rats were randomly divided into model group,puerarin group,lipopolysaccharide(LPS)group,and LPS+puerarin group after successful modeling.Another 15 rats were selected as sham operation group.The rats in puerarin group were intraperitoneally injected with 120 mg/kg puerarin once a day for 7 days.The rats in LPS group were intraperitoneally injected with 0.5 mg/kg LPS once.The rats in LPS+puerarin group were intraperitoneally injected with 0.5 mg/kg LPS,and then 120 mg/kg puerarin was injected once a day for 7 consecutive days.The rats in sham operation group and model group were intraperitoneally injected with the same amount of saline during the experiment.Effective refractory period(ERP)and ventricular fibrillation threshold were detected after VA induced by programmed electrical stimulation.Body surface electrocardiogram of rats was detected by limb lead electrocardiogram machine.Serum tumor necrosis factor-α(TNF-α)and interleukin-1β(IL-1β)levels were detected by enzyme linked immunosorbent assay(ELISA).Tripheye tetrazolium chloride(TTC)staining was used to observe the myocardial infarction area of rats.Western Blot was used to detect the expression levels of nuclear factorκB(NF-κB)pathway-related proteins in myocardial tissue.Results:Compared with model group,VA induction rate,T wave amplitude,ST segment elevation amplitude,myocardial infarction area ratio,serum TNF-αand IL-1βlevels,p-p65 relative expression level were decreased,ERP was prolonged,ventricular fibrillation threshold,inhibitor of NF-κBα(IκBα)relative expression level were increased,QT interval was shortened in puerarin group,VA induction rate,T wave amplitude,ST segment elevation amplitude,myocardial infarction area ratio,serum TNF-αand IL-1βlevels,p-p65 relative expression level were increased,ERP was shortened,ventricular fibrillation threshold,IκBαrelative expression level were decreased,QT interval was prolonged in LPS group,all P<0.05.Compared with puerarin group,VA induction rate,T wave amplitude,ST segment elevation amplitude,myocardial infarction area ratio,serum TNF-αand IL-1βlevels,p-p65 relative expression level were increased,ERP was shortened,ventricular fibrillation threshold,IκBαrelative expression level were decreased,and QT interval was prolonged in LPS+puerarin group,all P<0.05.Compared with LPS group,the VA induction rate,T wave amplitude,ST segment elevation,myocardial infarction area ratio,serum TNF-αand IL-1βlevels,and p-p65 relative expression level in the LPS+puerarin group were decreased,the ERP was prolonged,the ventricular fibrillation threshold and the relative expression level of IκBαwere increased,and the QT interval of ECG was shortened,all P<0.05.Conclusion:Puerarin can improve VA after MI in rats and affect the surface electrocardiogram parameters.The mechanism may be related to the regulation of NF-κB pathway.