Taurine Prevents the Electrical Remodeling in Ach-CaCl2 Induced Atrial Fibrillation in Rats

Objective: To study the preventive actions and mechanism of taurine on the electrical remodeling in atrial fibrillation (AF) rats. Methods: Male Wistar rats were injected with the mixture of acetylcholine (Ach) (66 mu g/mL)-CaCl2 (10 mg/mL) (i. v.) for 7 days to establish AF model. Taurine was administered in drinking water 1 week before or at the same time of AF model establishment. The duration of AF was monitored by recording ECG of rats during the model establishment. At the end of the experiment, left atrial appendages were cut down to measure the effective refractory period (ERP) by S1-S2 double stimulation method; atrial tissues were collected in order to detect the concentration of K+ and taurine by flame atomic absorption spectrometry and ELISA respectively; total RNA were extracted from the atrium, gene expressions of Kv1.5, Kv4.3, Kir2.1, Kir3.4 were detected by semi-quantitative RT-PCR. Results: Taurine administration effectively shortened the AF duration of rats and prolonged atrial ERP than the model and taurine depleted rats. In addition, atrial K+ level in taurine treated groups was significantly reduced nearly to the normal level. Moreover, the mRNA expression levels of Kir3.4 and Kv1.5 were significantly increased in the taurine preventive treated groups. Conclusions: Taurine can prevent the atrial electrical remodeling and decrease the duration of AF in rats by reducing the atrial K+ concentration and up-regulating mRNA expression levels of Kir3.4 and Kv1.5.

目的：研究牛磺酸对心房颤动（AF）大鼠电重构的预防作用及其机制。方法：雄性Wistar大鼠静脉注射乙酰胆碱（Ach）（66μg/mL） - 氯化钙（CaCl₂）（10mg/mL）的混合液，连续7天以建立AF模型。在AF模型建立前1周或同时在饮用水中给予牛磺酸。在模型建立过程中通过记录大鼠心电图监测AF持续时间。实验结束时，取下左心耳，采用S1 - S2双刺激法测量有效不应期（ERP）；收集心房组织，分别通过火焰原子吸收光谱法和酶联免疫吸附测定法检测K⁺和牛磺酸的浓度；从心房提取总RNA，通过半定量逆转录 - 聚合酶链反应检测Kv1.5、Kv4.3、Kir2.1、Kir3.4的基因表达。结果：与模型组和牛磺酸缺乏组大鼠相比，牛磺酸给药有效缩短了大鼠AF持续时间并延长了心房ERP。此外，牛磺酸治疗组的心房K⁺水平显著降低，接近正常水平。而且，在牛磺酸预防性治疗组中，Kir3.4和Kv1.5的mRNA表达水平显著升高。结论：牛磺酸可通过降低心房K⁺浓度以及上调Kir3.4和Kv1.5的mRNA表达水平来预防大鼠心房电重构并减少AF持续时间。