持续房颤患者的2型小电导钙激活钾通道(KCNN_2)基因表达研究

Expression of type 2 small conductance calcium activated potassium channels (KCNN_2) gene in sustained atrial fibrillation

目的 2型小电导钙激活钾通道(SK2)的功能亚基由KCNN2(Potassium intermediate/small conductance calcium-activated channel,subfamily N,member 2)基因编码。本研究通过分析持续心房纤颤(以下简称房颤)患者的KCNN2基因表达情况探讨其与房颤的相关性。方法将我院心胸外科自2012年7月—2013年7月期间收治的25例风湿性心脏病实施二尖瓣置换成形术的持续性房颤患者作为持续房颤组,其中2例患者既往合并脑栓塞;将同期收治的窦性心律患者20例作为窦性心律组。取两组患者在体外循环插管前的新鲜右心耳组织,分别用于逆转录聚合酶链反应(RT-PCR)。结果与持续房颤组比较,窦性心律组患者的二尖瓣狭窄病变较少,左房内径及心胸比率则较大,两组比较差异有统计学意义(P<0.05),两组其他各项指标比较无统计学差异(P>0.05)。持续房颤组的KCNN2与内参基因表达水平的比值明显低于窦性心律组(P<0.05),表明持续房颤组患者心房组织的KCNN2基因表达水平降低。结论与以往的动物实验结果截然不同,人发生持续房颤后KCNN2基因表达水平降低,在防治动物阵发性房颤中显示有效的特异性阻断剂对持续性房颤患者是否有效尚需深入研究。

Objective To analyze type 2 small conductance calcium activated potassium channels （ KCNN2 ） gene expression in the patients with persistent atrial fibrillation （Af）. Methods During July 2012 to July 2013, cardiothoracic surgery （ mitral valve replacement） were performed in 25 inpaticnts with rheumatic heart disease accompanied by persistent Af （ Af group） in our hospital, including 2 ones complicated with cerebral embolism. Meanwhile, another 20 patients with sinus rhythm （ sinus rhythm group） were enrolled in the study. Fresh tissues of right atrial appendage were taken out for reverse transcription polymerase chain reaction （RT-PCR） in advance of extracorporeal circulation intubation. Results Compared with the persistent Af group, the sinus rhythm group suffered from significantly less mitral valve stenosis and possessed significantly larger left atrial diameter and cardiothoracic ratio （ P 〈 0.05 ）. There were no significant differences in other indicators between the two groups（ P 〉 0.05 ）. The ratio of KCNN2 to internal reference gene expression was significantly lower in the Af group than in the sinus rhythm group （ P 〈 0.05 ）, suggesting that the KCNN2 gene expression in the atrial tissue of the Af group continued to reduce. Conclusion Different from the outcomes of animal experiments in the past, the level of KCNN2 gene expression in the patients with sustained Af is reduced. Whether the specific blockade applied to prevention and treatment of paroxysmal Af in animal is effective or not needs to be further researched.