Increased Atrial Expression Of HCN4 Gene MRNA In Atrial Fibrillation Patients With Mitral Stenosis Of Rheumatic Heart Disease

Objective: Through the analysis of HCN4 gene expression in rheumatic heart disease patients with mitral valve stenosis and in control group ,we aim to lay the theoretical foundation of atrial fibrillation, and to explore the possible adjustment mechanism of atrial fibrillation in mitral valve stenosis of rheumatic heart disease.Methods: 1. Through semi-quantitative reverse transcriptase-PCR method (RT-PCR) to study HCN4 gene mRNA expression at two group rheumatic heart disease patients with mitral valve stenosis, one group with atrial fibrillation as experimental group and the other without atrial fibrillation as control group. We used the ratio of HCN4 gene mRNA expression and theβ-actin mRNA expression for evaluating the mRNA expression level of HCN4 gene.2. Through the sequence analysis of HCN4 gene PCR product , we studied the homology of HCN4 gene.3. Through the application of fluorescent dye SYBR GreenⅠ, we set up real-time fluorescence quantitative-PCR (Real Time PCR) to detect HCN4 gene mRNA in right atrial appendage tissue, and quantitative result serve as HCN4 mRNA gene expression and theβ-actin mRNA expression.Results: 1. By RT-PCR analysis of atrial fibrillation patients with mitral valve stenosis of rheumatic heart disease and control group, the ratio of HCN4 gene mRNA expression andβ-actin mRNA expression values (?) were 0.685±0.168 and 0.127±0.012 respectively, the difference of the two groups was significant (t=20.351, P＜0.01).2. The homology of HCN4 gene cDNA sequence was 100%, that indicates the amplification product was PCR target gene.3. Setting up the real-time fluorescence quantitative PCR method at 10~3-10~7 copies/ul of the standard dilution, and the correlation coefficient is 0.999. The quautitative result of the ratio of HCN4 gene mRNA expression andβ-actin mRNA expression values (?) in patients with atrial fabrillation and the control group were 1.323±1.226 and 0.116±0.192 (t=5.877, P＜0.01) respectively, which indicated that the HCN4 gene expression signicantly rise in atrial fibrillation patients with mitral valve stenosis of rheumatic heart disease.Conclusion: 1.HCN4 gene expression in atrial fibrillation patients with mitral valve stenosis of rheumatic heart disease increases, which may affect the hyperpolarization-activated cation current (If), resulting in atrial fibrillation.2. Controling atrial HCN4 gene expression and regulating hyperpolarization-activated cation current (If) probably prevent atrial fibrillation appearence and stop atrial fibrillation maintenance.