睡眠剥夺致大鼠心律失常的KV4.3钾离子通道机制研究

The mechanism of KV4.3 voltage-gated potassium channel in arrhythmia induced by sleep deprivation in rat

目的观察睡眠剥夺后大鼠的心电图改变及其心室肌组织KV4.3钾离子通道mRNA和蛋白表达情况,探讨睡眠剥夺致心律失常的发生机制。方法 48只清洁级健康成年雄性SD大鼠随机分6组(每组8只):正常对照(CC)组,大平台实验(TC)组及睡眠剥夺(SD)13、5、7、d组。睡眠剥夺(SD)组以改良多平台睡眠剥夺法(MMPM)建立睡眠剥夺模型,观察13、5、、7d睡眠剥夺后大鼠心电图的变化,并通过RT-PCR及Western blotting方法检测大鼠心肌组织KV4.3钾离子通道基因的mRNA和蛋白表达水平。结果睡眠剥夺后大鼠心电图改变以心律失常为主:与CC组大鼠比较,TC组大鼠心电图表现为窦性心动过速;SD1d组出现频发房性早搏;SD3d组出现室性心律失常(表现为频发的多形性室性早搏及短阵室速);SD5d组呈不完全性右束支传导阻滞波形;SD7d组房性心律与室性心律分离,呈三度房室传导阻滞波形,伴室性逸搏、窦性停搏,ST段明显抬高并与高尖的T波融合。随着睡眠剥夺时间的延长,心肌组织KV4.3钾离子通道mRNA及蛋白表达水平均呈逐渐下调趋势,至睡眠剥夺7d时,mRNA及蛋白表达量分别仅为正常大鼠的1/9和1/4。结论睡眠剥夺可致大鼠心律失常,并随剥夺时间的延长而加重;心肌组织KV4.3钾离子通道基因表达下调可能是睡眠剥夺致心律失常的机制之一。

Objective To investigate the effect of sleep deprivation（SD） on the changes in electrocardiogram and mRNA and protein expression of KV4.3 voltage-gated potassium channel in rats,and explore the related mechanisms of arrhythmia induced by SD.Methods A total of 48 adult male SD rats were randomly divided into 6 groups（8 each）： normal control（CC） group,tank control（TC） group,1-,3-,5-and 7-day SD group.Animal model of SD was established by modified multiple platform method,and electrocardiogram was recorded on 1st,3rd,5th,and 7th of experiment.Protein and mRNA expressions of KV4.3 voltage-gated potassium channel were measured by real-time PCR and Western blotting analysis.Results The main changes on electrocardiogram following SD were arrhythmia.Compared with the CC group,rats in TC group showed sinus tachycardia in electrocardiogram： frequent atrial premature beats were observed one day after SD;ventricular arrhythmias,such as frequent polymorphic ventricular premature beats and paroxysmal ventricular tachycardia were observed three days after SD;incomplete right bundle branch block wave occurred five days after SD;the electrocardiogram showed third-degree atrioventricular（AV） block wave seven days after SD,which indicated atrial arrhythmia and ventricular arrhythmia respectively.Ventricular escape beat,sinus arrest as well as the fusion of obviously elevated ST segment and T-wave were also observed.The expression levels of KV4.3 voltage-gated potassium channel decreased with prolongation of SD time.The expression of mRNA and protein of KV4.3 potassium channel in 7-day SD rats were only the one ninth and one fourth of levels in CC group.Conclusion Sleep deprivation can cause arrhythmia,and decreased expression of KV4.3 voltage-gated potassium channel may possibly be one of the reasons of arrhythmia induced by SD.