摘要
为观察家兔短期快速心房起搏所致心房肌电重构及其对钙平衡调节蛋白mRNA表达水平的影响 ,探讨心房肌电重构的发生机制 ,取新西兰大耳白兔 36只 ,随机分为 6组 ,经颈内静脉切开置入电极导管 ,以最快的心房 1∶1起搏的频率于右房行快速心房起搏 ,监测起搏前后心房有效不应期 (AERP)的变化 ,按分组分别于起搏 0 .5 ,1,2 ,4 ,8h后终止起搏 ,取右房组织 ,行半定量逆转录 聚合酶链式反应测定钙平衡调节蛋白基因表达的相对水平。结果 :快速心房起搏后AERP缩短 ,起搏后 0 .5h内AERP变化速率最大 ,最小值出现在快速心房起搏后 8h ,在 0 .5h后的整个短期起搏过程中变化不大 ;0 .5h至 8h的快速心房起搏使肌浆网钙泵和L型Ca2 + 通道基因表达水平逐渐下调 ,至起搏后 4h较起搏前有显著性差异 ;Na+ Ca2 + 交换的基因表达水平上调 2 3.71% ,但无统计学意义。磷酸受纳蛋白、Ryanodine受体的基因表达水平无明显变化。结论 :心房肌电重构的电生理变化发生于快速心房起搏0 .5h ,起搏 4h可引起钙平衡调节蛋白基因表达的变化 ,推测心房肌电重构的形成有细胞内钙超载机制的参与。
To investigate the effect of short-term atrial rapid pacing on mRNA expression of calcium-handling proteins, thirty-six rabbits were randomly divided into six groups (n=6 for each). The electrode catheter was localized in right atrium through right internal jugular vein. Pacing was performed up to maximal atrial capture rate for 0,0.5,1,2,4,8hours respectively. Right atrium tissue was obtained for measurement of calcium-handling proteins mRNA using reverse transcription-polymerase chain reaction (RT-PCR). Results:There was a prompt decrease in AERP as the result of rapid atrial pacing. The minimum value of AERP occurred after 8 hours of rapid atrial pacing and an initial drop was taken in first 0.5 hour. The mRNA level of L-type Ca 2+ channel α1C subunit and sarcoplasmic reticulum calcium ATPase decreased gradually and progressively during a 0.5 to 8hours pacing period. Significant difference was observed 4 hours after the onset of pacing. No significant difference was observed in the mRNA level of sodium-calcium exchanger, phospholamban and Ryanodine receptor type2.Conclusion: Even short-term atrial rapid excitation could decrease the mRNA level of L-type Ca 2+ channel α1C subunit and sarcoplasmic reticulum calcium ATPase. This change implies that calcium loading is at least partially responsible for atrial electrical remodeling.
出处
《中国心脏起搏与心电生理杂志》
2003年第6期454-457,共4页
Chinese Journal of Cardiac Pacing and Electrophysiology
