替米沙坦对猪心动过速性心肌病心肌细胞Fas/FasL、FADD、Bcl-2/Bax、caspase-3蛋白的影响

The effect of telmisartan on Fas/FasL, FADD, Bcl-2/Bax, and caspase-3 in cardiomyocytes of porcine tachycardiomyopathy model

目的 研究替米沙坦对猪心动过速性心肌病（tachycardiomyopathy,TCM）心肌细胞Fas/FasL、Fas相关死亡结构域（Fas-associated death domain,FADD）、Bcl-2/Bax、caspase-3蛋白的影响,探讨替米沙坦对心肌细胞的保护作用及其作用机制.方法 18头家猪随机分为3组（每组n=6）：快速右心房起搏组（TCM组）,实验猪植入永久起搏器,起搏频率500次/min;快速右心房起搏加替米沙坦组（TCM＋TS组）,起搏器植入前3天至起搏2周后,每日给予替米沙坦（1.5 mg·kg-1·d-1）混于饲料中喂服;对照组,实验猪未植入起搏器也未服药.每周记录1次心电图,实验前后经胸心脏超声观测猪左心室舒张末期内径（LVEDD）和左心室射血分数（LVEF）.2周后处死动物,取左心室组织,Western blot技术检测Fas/FasL、FADD、Bcl-2/Bax、caspase-3蛋白含量,逆转录聚合酶链反应（RT-PCR）检测fas、caspase-3 mRNA转录水平.结果 TCM组较对照组左心室心肌细胞Fas/FasL、FADD、Bcl-2/Bax、caspase-3蛋白表达量均明显增高（P〈0.05）,TCM＋TS组较TCM组Fas/FasL、FADD、Bcl-2/Bax、caspase-3蛋白表达量均明显降低（P〈0.05）.TCM组较对照组左心室心肌细胞fas及caspase-3 mRNA表达明显增高（P〈0.05）,TCM＋TS组较TCM组fas及caspase-3 mRNA表达明显降低（P〈0.05）.Fas与caspase-3蛋白表达呈明显正相关（r=0.987,P〈0.01）;fas与caspase-3 mRNA表达呈明显正相关（r=0.950,P〈0.01）.结论 替米沙坦通过抑制Fas/FasL通路相关蛋白的表达,进而减少细胞凋亡,延缓TCM病情进展.

Objective To investigate the effect of telmisartan on Fas/FasL, Fas - associated death domain （FADD） , Bcl- 2/Bax, and caspase- 3 in cardiomyocytes of porcine tachycardiomyopathy （TCM） model and to expound the protective effect and mechanism of telmisartan in cardiomyocytes. Methods Eighteen healthy pigs were ran- domly divided into 3 groups （n = 6 each）. Rapid right atrial pacing group （TCM group） ： permanent pacemaker was im- planted into experimental pigs, and pacemaker electrodes were imbedded into right anricle of pigs through vena jugularis interna （pacing frequency at 500 times/rain ）. Rapid right atrial pacing and telmisartan treating group （TCM ＋ TS group） ： pacemaker was implanted as TCM group, telmisartan （ 1.5 mg ~ kg - l . d - 1 ） mixed with daily forage was fed to the animals beginning 3 days before implantation and continued until day 14 after implantation. Control group： neither pacemaker was implanted nor telmisartan was administered. Electrocardiogram （ECG） examination was implemented to each animal, left ventricular end - diastolic diameter （LVEDD） and left ventricular ejection fraction （LVEF） were meas- ured using transthoracic echocardiography at the beginning and end of experiment. At day 14 after implantation, animals were euthanized and tissues of left ventricle were harvested. The contents of Fas/FasL, FADD, Bcl - 2/Bax, and caspase - 3 were detected by Western blot. The expression of fas and capase - 3 mRNA was detected using reverse tran- scription polymerase chain reaction （RT - PCR） method. Results The expression of the protein of Fas/FasL, FADD,Bel - 2/Bax, and caspase - 3 in cardiomyocytes of left ventricle raised obviously in TCM group compared to control group （P 〈0.05 ）. The expression of the protein of Fas/FasL FADD, Bel - 2/Bax, and easpase - 3 in eadiomyoeytes of left ventricle decreased obviously in TCM ＋ TS group compared to TCM group （ P 〈 0.05）. The expression of the mRNA of Fas and caspase -3 in eardiomyoeytes of left ventricle raised obviously in TCM group eompared to control group （P 〈 0.05 ）. The expression of the mRNA of Fas and caspase - 3 in cadiomyocytes of left ventricle decreased obviously in TCM ＋ TS group compared to TCM group （ P 〈 O. 05 ）. Correlated statistics datas showed that the expression of the protein of Fas and easpase - 3 was positively con＇elated （r = 0. 987, P 〈 0.01 ）. The expression of the m]]NA of Fas and caspase - 3 was positively correlated （r = 0. 950, P 〈 0.01 ）. Conclusion Telmisartan can postpone TCM progression by decrea- sing apoptosis of cardiomyocytes through suppression of Fas/FasL pathway.