肌浆网钙ATP酶过表达对心房颤动兔心房及L型钙通道a1c蛋白表达的影响

Effects of sarco/endoplasmic reticulum Ca^(2+)-ATPase2a overexpression on the protein expression of L-type voltage dependent calcium channel a1c subunit in a rabbit model of acute atrial fibrillation

目的探讨心肌肌浆网钙ATP酶2a(SERCA2a)基因过表达,对兔急性心房颤动(AF)的心房肌L型电压依赖钙通道蛋白alc亚单位(LVDCCalc)表达的影响。方法 48只成年新西兰兔,随机分成为房颤组(AF组,n=12)、9-型腺相关病毒+增强型绿色荧光蛋白组+房颤组(rAAV9+EGFP+AF组,n=12)、9-型腺相关病毒+肌浆网钙ATP酶2a+增强型绿色荧光蛋白组+房颤组(rAAV9+SERCA2a+EGFP+AF组,n=12),并设假手术组作为对照(Control组,n=12)。rAAV9+EGFP+AF组和rAAV9+SERCA2a+EGFP+AF组起搏前30 d开胸心包腔内注射包含报告基因的rAAV9-EGFP和包含靶基因的rAAV9-SERCA2a-EGFP各500μL(1×1012v.g/μL)。转染30 d后,AF组、rAAV9+EGFP+AF组和rAAV9+SERCA2a+EGFP+AF组,以600 BPM刺激频率,持续起搏兔右心房24h制作AF模型。处死各组动物,倒置荧光显微镜下观察右心房肌组织EGFP表达情况,行HE染色对右心房组织形态检查,应用免疫组化技述检测SERCA2a蛋白及LVDCCalc蛋白在心房肌中的表达情况。结果 rAAV9+EGFP+SERCA2a+AF组SERCA2a蛋白及LVDCCalc蛋白表达量显著高于AF组和rAAV9+EGFP+AF组(P<0.05),但与对照组比较差异无显著性。结论心房肌转SERCA2a基因,显著减少了急性房颤心房肌的LVDCCa1c蛋白表达的降低,有逆转急性AF电重构的作用。

Objective To explore the effects of sareo/endoplasmic reticulum calcium ATPase2a （SERCA2a） overexpression on the protein expression of L-type voltage dependent calcium channel （LVDCCalc） subunit in rabbit mod- els of atrial fibrillation （AF）. Methods Forty-eight New Zealand rabbits were randomly divided into four groups （ n = 12） , including control group, AF group, rAAV9 ＋ EGFP ＋ AF group and rAAV9 ＋ SERCA2a ＋ EGFP ＋ AF group. rAAV9-EGFP and rAAVg-SERCA2a-EGFP in a dose of 1.0 ~ 1012 v. g/μL for each animal were injected into pericardium of the animals of rAAV9 ＋ EGFP ＋ AF and rAAV9 ＋ SERCA2a ＋ EGFP（ enhanced green fluorescent protein） ＋ AF groups at thirty days before rapid atrial pacing. Thirty days after gene transfection, AF was induced by rapid atrial pacing （600 beats/rain） for 24 hours in each animal of the AF group, rAAV9 ＋ EGFP ＋ AF group and rAAV9 ＋ SERCA2a ＋ EGFP ＋ AF group. The animals of the control group were not paced. The animals were sacrificed to observe the expression of green flu- orescent protein in the frozen sections of myocardium of rabbits in the rAAV9 ＋ EGFP ＋ AF group under an inverted fluo- rescence microscope, to assess the right atrial tissue morphology and detect the expressions of SERCA2a protein and LVDC- Calc protein in the fight atrial tissue in each group using HE staining and immunohistochemistry at 24 hours after pacing. Results Compared with the AF group and rAAV9 ＋ EGFP ＋ AF group （P 〈 0. 05 ）, expressions of SERCA2a protein and LVDCCalc protein in the right atrium of rabbits of the rAAV9 ＋ SERCA2a ＋ EGFP ＋ AF group were significantly upregulat- ed, but there was no significant difference in expressions of SERCA2a protein and LVDCCalc protein in the right atrium of rabbits among rAAV9 ＋ SERCA2a ＋ EGFP ＋ AF group, AF group and rAAV9 ＋ EGFP ＋ AF group （P 〉 O. 05 ）. Conclu- sions The transgenic SERCA2a-overexpression in atrial tissue significantly reduces the down-regulation of the expression of LVDCCalc protein and reverse acute AF electrical remodeling in rabbit models of atrial fibrillation.