再灌注房性心律失常大鼠心房肌电传导降低与Cx40和Cx43的关系

Relationship between decreased atrial myoelectric conduction and Cx40 and Cx43 in rats with reperfusion atrial arrhythmia

目的评价再灌注房性心律失常大鼠心房肌电传导降低与缝隙连接蛋白40(Cx40)和Cx43的关系。方法取成功建立的Langendorff离体灌注模型的心脏16个,采用随机数字表法分为对照组(C组)和缺血再灌注组(IR组),每组8个。根据是否发生再灌注房性心律失常将IR组分为再灌注非房性心律失常亚组(R-NAA组)和再灌注房性心律失常亚组(R-AA组)。C组使用37℃K-H液平衡灌注120 min。IR组使用37℃K-H液平衡灌注30 min,停止灌注后注射4℃Thomas液20 ml/kg使心脏停搏60 min,心脏周围用4℃Thomas液保护,停搏30 min时复灌4℃Thomas液10 ml/kg,然后再次灌注37℃K-H液30 min。于平衡灌注120 min或再灌注30 min时,测定右心房有效不应期(ERP)和传导速度(CV),采用Western blot法检测右心房肌Cx40和Cx43的表达,计算Cx40/Cx40+Cx43比值和Cx43/Cx40+Cx43比值。结果IR组再灌注房性心律失常发生率为38%。与C组比较,R-NAA组和R-AA组ERP延长,CV降低,Cx40和Cx43表达下调,Cx40/Cx40+Cx43比值升高,Cx43/Cx40+Cx43比值降低(P<0.05);与R-NAA组比较,R-AA组ERP延长,CV降低,Cx40和Cx43表达下调,Cx40/Cx40+Cx43比值升高,Cx43/Cx40+Cx43比值降低(P<0.05)。结论再灌注房性心律失常大鼠心房肌电传导功能降低可能与Cx40和Cx43表达下调有关。

Objective To evaluate the relationship between decreased atrial myoelectric conduction and gap junction protein 40(Cx40)and Cx43 in rats with reperfusion atrial arrhythmia.Methods Sixteen Langendorff-isolated heart perfusion models were randomly divided into control group(group C)and ischemia-reperfusion group(group IR),with 8 rats in each group.According to whether the atrial arrhythmia occurred after reperfusion,group IR was further divided into reperfusion non-atrial arrhythmia subgroup(group R-NAA)and reperfusion atrial arrhythmia subgroup(group R-AA).Group C was balanced perfusion with K-H solution(37℃)for 120 min.In group IR,hearts were perfused with K-H solution(37℃)for 30 min,perfusion was then stopped,Thomas solution(4℃,20 ml/kg)was injected to induce cardiac arrest for 60 min,the surrounding of the heart was protected with 4℃Thomas solution,and hearts were perfused with Thomas solution(4℃,10 ml/kg)again after 30 min of cardiac arrest and then with K-H solution 37℃for 30 min.At 120 min of equilibration or 30 min of reperfusion,the effective refractory period(ERP)and conduction velocity(CV)of the right atrium were measured,the expression of Cx40 and Cx43 in the right atrial myocardium was detected by Western blot,and ratio of Cx40 to Cx40+Cx43 and the ratio of Cx43 to Cx40+Cx43 were calculated.Results The incidence of reperfusion atrial arrhythmia was 38%in group IR.Compared with group C,ERP was significantly prolonged,CV was decreased,the expression of Cx40 and Cx43 was down-regulated,the ratio of Cx40 to Cx40+Cx43 was increased,and the ratio of Cx43 to Cx40+Cx43 was decreased in R-NAA and R-AA groups(P<0.05).Compared with group R-NAA,ERP was significantly prolonged,CV was decreased,the expression of Cx40 and Cx43 was down-regulated,the ratio of Cx40 to Cx40+Cx43 was increased,and the ratio of Cx43 to Cx40+Cx43 was decreased in group R-AA(P<0.05).Conclusion The decreased atrial myoelectric conduction may be related to the down-regulation of Cx40 and Cx43 expression in rats with reperfusion atrial arrhythmia.