中文摘要：

目的探讨腺病毒介导超极化激活环核苷酸门控通道（HCN4）在猪左心室过度表达的电生理效应。方法应用细菌内同源重组法构建携带人HCN4基因的重组腺病毒载体（Ad-HCN4）和绿色荧光蛋白的重组腺病毒载体（Ad-GFP）。实验动物随机分成3组：Ad-HCN4组（n=6），Ad-GFP组（n=5）和PBS组（n=3）。腺病毒或PBS注入到Yorkshire猪左心室游离壁，3-4d后行房室结消融造成完全性房室阻滞，记录体表心电图并进行心内起搏标测。注射部位心肌组织用酶分离后获得单个心肌细胞，膜片钳记录起搏电流（If）和内向整流钾电流（Ik1）。结果Ad-HCN4组室性心律频率显著快于Ad-GFP组和PBS组，心腔内起搏标测证实该心律起源于Ad-HCN4注射区且可被异丙肾上腺素所调节，无水乙醇消融Ad-HCN4注射区后该心律消失。Ad-HCN4转染心肌细胞表达较大的If;Ik1在3组间差异无统计学意义。结论腺病毒介导HCN4通道基因心室局部高表达发挥了生物起搏器的作用。

英文摘要：

Objective The hyperpolarization-associated, cyclic nucleotide-gated cation channels （HCN4） has been identified as a key factor of cardiac pacemaker activity. The present study investigated the HCN4 for potential use as a biological pacemaker. Methods Two adenoviral vector containing HCN4 and GFP （Ad-HCN4） or GFP alone （Ad-GFP） were constructed. The experimental pigs were separated into three groups. Three or four days after gene injection, the complete AV block was created by radiofrequency catheter. Electrocardiography （ECG） and inter-cardiac electrophysiological mapping were used. Then the injected cardiac tissue was seized, single myocytes were obtained by digestion, patch clamp technique was used to test If and Ik1. Results Sustained ECG recording revealed that a rapid and stable idioventricular rhythm was shown in Ad-HCN4 treated group. Pace mapping indicates that the rapid rhythm originated from the Ad-HCN4 injection region. The rhythm could be modulated by β-adrenergic agonist isoproterenol. The ventricular myocytes trans-fected with HCN4 gene exhibited significantly increased If current. IK1 has no difference in three groups. Conclusion Site-specific gene therapy for heart is feasible using adenovirus vector for over-expressing HCN4 channels.