心房肌钙转运调控蛋白的表达改变与增龄及心房颤动关系的实验研究

Experimental study about alterations in the expression of atrial calcium transport handling proteins during aging and atrial fibrillation

目的:为论证是否存在心房肌细胞膜L-型钙通道蛋白和细胞内肌质网钙转运调控蛋白异常表达伴随增龄而显现,致使心肌细胞内钙稳态遭到破坏,以期阐明增龄性心房颤动(房颤)心房电重构的分子机制。方法:通过持续快速心房起搏建立慢性房颤犬模型,用实时荧光定量聚合酶反应(QRT-PCR)和蛋白免疫印迹(Western blot)方法检测4组犬(成年和老年窦性心律犬、成年和老年慢性房颤犬)左心房心肌钙转运调控蛋白在mRNA和蛋白质表达水平的变化。结果:窦性心律时,与成年犬比较,老年犬心电图P波持续时间显著延长,P波离散度显著增大,在mRNA和蛋白质表达水平方面,窦性心律时,与成年犬比较,老年犬左心房肌L-钙通道a1c亚基(LVDCCa1c)显著降低,而Ca2+-ATPase显著升高(P<0.05),RYR2、IP3R1和PLN普遍显示出上调趋势,但无统计学差异(P>0.05);与窦性心律犬比较,相同年龄组房颤犬除受磷蛋白(PLN)之外,LVDCCa1c和肌浆网钙转运调控蛋白均显著下调,尤其是老年房颤犬这种下调趋势更加明显(P<0.05)。结论:伴随增龄与房颤而显现的左房电生理和钙转运调控蛋白特异性改变可能是增龄性房颤心房电重构的分子机制。

Objective：This study is to investigate whether or not the abnormality of intracellular Ca2＋handling protein augment with aging,creating a substrate for initiation and maintenance of atrial fibrillation（AF）.Method：Four groups of dogs were studied：adult and old dogs in sinus rhythm（SR）and with chronic AF（CAF）induced by rapid atrial pacing.The mRNA and protein expressions of Ca2＋handling protein were measured by Quantitative Real-Time Polymerase Chain Reaction（real-time qRT-PCR）and Western-blot method.Result：Compared to adult group,the duration of P waves was prolonged,the P wave dispersion was increased,the mRNA and protein expressions of of L-type calcium channel a1 cwas decreased,whereas the expressions of calcium adenosine triphosphatase was increased.Moreover,compared to SR groups,the expressions of intracellular Ca2＋handling protein except phospholamban was significantly decreased in both adult and aged groups specifically in the latter with AF（all P〈0.05）.Conclusion：These aging-induced electrophysiological and intracellular Ca2＋handling protein changes might be molecular mechanisms for AF during aging.