螺内酯对高甲状腺素诱导的兔心房颤动和心房重构的影响

目的:探讨螺内酯对高甲状腺素诱导的兔心房颤动(AF)和心房重构的影响。方法:新西兰兔33只随机分为3组:正常对照组(C)、高甲状腺素组(H)和螺内酯组(S)。H和S组腹腔注射甲状腺素4周建立兔甲亢性AF模型,之后,S组给予螺内酯灌胃2周。给药结束后,通过心内电生理高频刺激诱发AF,计算AF诱发率,测量心房有效不应期(AERP)。荧光定量PCR测定L型钙通道亚基(Cav1.2)、钾通道相关亚基(Kv1.5、Kv4.3)和缝隙连接蛋白(Cx40、Cx43)的mRNA表达,Western blot和免疫组化测定上述指标的蛋白表达。结果:螺内酯降低AF诱发率。H组和S组的AERP无明显差异(P0.05)。S组Cav1.2蛋白表达水平明显高于H组(P0.05)。S组Kv1.5的mRNA和蛋白表达水平均明显低于H组(P0.05),S组Kv4.3的蛋白表达水平显著低于H组(P0.05)。S组Cx43的mRNA表达水平明显低于H组(P0.01),S组Cx40的蛋白表达水平显著低于H组(P0.05)。结论:螺内酯可降低高甲状腺素所致的AF诱发率,改善其引起的心房重构。

Effect of spironolactone on hyperthyroxine-induced atrial fibrillation and atrial remodeling in rabbits

AIM: To detect the effect of spironolactone on hyperthyroxine-induced atrial remodeling. METHODS: New Zealand rabbits were divided into control group (C), hyperthyroxine group (H) and spironolactone group (S). Thyroxin was given to the rabbits in group H and group S by intraperitoneal injection for 4 weeks, and then spironolactone was given in group S by gavage for 2 weeks. Atrial fibrillation (AF) was induced by "burst" stimulation after administration. The inducing rate of AF and atrial effective refractory period (AERP) were tested by intra-cardiac electrophysiologic instrument. The expression of AF-related Ca²⁺ channel (Cav1.2), K⁺ channels (Kv1.5 and Kv4.3) and connexins (Cx40 and Cx43) at mRNA and protein levels was detected by real-time PCR, immunohistochemistry and Western blot. RESULTS: Spironolactone reduced the inducing rate of AF. No significant difference of AERP between group H and group S was observed (CONCLUSION: Spironolactone attenuates the hyperthyroxine-induced atrial remodeling in rabbits, and reduces the susceptibility of the myocardium to AF.