高甲状腺素对心房和肺静脉缝隙连接、电生理特性的影响

Effects of hyperthyroidism on the electrophysiological characteristics between atrium and gap junction between atrium and pulmonary vein

目的研究高甲状腺素对心房和肺静脉缝隙连接、电生理特性的影响。方法24只实验兔随机分为正常对照组和甲亢组。测定心房有效不应期(AERP),然后取心房、肺静脉组织,用Western blot和半定量逆转录聚合酶链反应法分别测定连接蛋白43(cx43)及连接蛋白40(Cx40)的蛋白表达和mRNA水平。结果甲亢组的AERP均明显短于对照组(P＜0．01),且AERP的频率适应性较对照组明显下降(P＜0．01)。甲亢组心房及肺静脉的Cx43蛋白和mRNA表达量较对照组明显增加,而Cx40的蛋白表达量低于对照组(P＜0．05)。心房及肺静脉的Cx40 mRNA表达量在两组之间差异无统计学意义。结论高甲状腺素可引起心房电生理重构和心房及肺静脉的缝隙连接重构。

Objective To investigate the effects of hyperthyroidism on the electrophysiological characteristics of atrium and gap junction between atrium and pulmonary vein. Methods Twenty-four rabbits were randomly divided into control group and hyperthyroid group. Atrium and pulmonary vein were dissected after the atrial effective refractory period （AERP） was measured. Cormexin 43 （Cx43） and Cormexin 40 （Cx40） protein and mRNA were determined by Western blot and semi-quantitative reverse transcription-polymerase chain reaction, respectively. Results In comparison with control group, AERP and rate adaption of AERP in hyperthyroid group were significantly shorter than that of control group （ P 〈 0.01 ）. The concentration of Cx43 protein in hyperthyroid group was significantly higher than that of control group, but Cx40 protein was significantly lower than that of control group （ P 〈 0.05）. The expression of Cx43 mRNA in atrium and pulmonary vein was found to be up-regulated in hyperthyroid group as compared with that of control group （ P 〈 0.01 ）. With the level of Cx40 mRNA, there was no significant difference between two groups. Conclusion Thyroid hormone could lead to remodeling of both atrial electrophysiology and gap junction between atrium and pulmonary vein.