心房颤动犬心房肌细胞2型理阿诺受体的分布和表达

The expression of RyR_2 in atrial myocytes during atrial fibrillation in dogs

目的探讨心房颤动(房颤)时心房肌细胞2型理阿诺受体表达和分布的改变。方法杂种犬10只,分为正常对照组和单纯房颤组,每组5只。单纯房颤组用起搏器进行房颤式快速起搏,起搏频率(500±20)次/min,正常对照组不植入起搏器。24周后取出心脏,用逆转录聚合酶链反应、免疫荧光染色技术检测犬心房肌细胞2型理阿诺受体在mRNA水平的表达和蛋白水平的表达和分布。结果与正常对照组比较,单纯房颤组犬2型理阿诺受体在mRNA和蛋白水平的表达明显低于正常对照组(P<0.05);在细胞质、细胞膜2型理阿诺受体分布均显著减少。结论房颤时心房肌细胞2型理阿诺受体表达下调,2型理阿诺受体可能不是心房肌细胞主要的钙信号调控的受体。

Objective To investigate the changes of expression and distribution of type-2 ryanodine receptor （RyR2） in atrial tissue during atrial fibrillation in dogs. Methods Ten adult mongrel dogs were randomly divided into 2 groups： 5 dogs underwent continuous rapid atrial pacing （500 ± 20）beats/min to create persistent atrial fibrillation, and the other 5 size-matched dogs without pacemaker implantation were. used as controls. Twenty-four weeks later, the dog＇ s hearts were taken out and the expression of RyR2 in canine atrial tissue was examined. The distribution of RyR2 was measured by immmunofluorescence staining. The mRNA and protein level of RyR2 were measured by reverse transcriptase-polymerase chain reaction and histochemistry. Results In atrial tissue of the dogs with atrial fibrillation, the distribution of RyR2 was found within the cytoplasm and cellular membrane of myocytes, but was not found in nuclear membrane and intercalated discs. The expression levels of RyR2 mRNA and protein were decreased significantly compared with the normal dogs （ P 〈 0.05）. Conclusions The expression of RyR2 is down-regnlated and the function of RyR2 is decreased during atrial fibrillation. The role of RyR2 in Ca^2＋ signal regulation may be not important during atrial fibrillation in dogs.