慢性心力衰竭大鼠心肌细胞凋亡及Fas基因、FasL（Fas蛋白配体）的变化

目的　本实验将探讨腹主动脉缩窄所致慢性心力衰竭大鼠心肌细胞凋亡与Fas及Fas蛋白配体 (FasLigand ,FasL)基因表达的变化 ,揭示二者与心力衰竭发展过程的关系。方法　以腹主动脉缩窄法建立大鼠慢性心力衰竭模型。 3 0只大鼠随机分成假手术组、手术左室代偿性肥厚组 (简称肥厚组 )及手术心衰组。采用原位末端脱氧核糖核苷酸转移酶介导的dUTP缺口末端标记法 (TUNEL)观察发生心衰的大鼠和同期仅左室肥厚而未发生心衰的大鼠的心肌细胞凋亡情况 ,同时以免疫组化ABC显色法分别检测Fas与FasL蛋白水平变化 ,以逆转录聚合酶链反应法检测Fas基因mRNA的表达改变 ,从而探讨心肌组织中Fas基因的蛋白与mRNA表达水平与心肌细胞凋亡的关系以及二者在心衰发展过程中的作用。结果　假手术组心肌中仅有少许心肌细胞凋亡 ,实施手术的代偿性肥厚组与心衰组大鼠均有心肌细胞凋亡发生 ,但心衰组心肌细胞凋亡的数目明显高于对照组。大鼠经腹主动脉缩窄术后 4周 ,左室肥厚而未发生心衰的大鼠其心肌组织Fas蛋白阳性染色指数明显高于假手术组 ,但Fas配体蛋白阳性染色指数与假手术组间无显著性差异 ;而发生心衰的大鼠其心肌组织Fas及Fas配体蛋白阳性染色指数明显高于肥厚组 ,差异有显著性意义 (P <0 0 5)。与假手术组和肥厚组相比

Changes of Apoptosis and Expression of Fas and FasL Genes in Heart Failure in Wistar Rats by Gradually Constricting the abdominal aorta

Objective To investigate myocardial apoptosis and the expression in Fas and Fas ligand (FasL) genes in myocardium of rats with congestive heart failure. Methods Model of chronic heart f ailure was created by gradually constricting the abdominal aorta of Wistar rats. Thirty rats were divided randomly into sham group, operated group-left ventricular compensated hypertrophy group and operated group-heart failure group. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and ABC immunohistochemical staining were used to detect the changes of apoptosis and protein expression of Fas and FasL genes.\ mRNA expression of Fas gene was evaluated by RT-PCR analysis. Results Few apoptotic myocardial cells were shown in sham-operated group, while apoptotic myocardial cells were found frequently both in congestive heart failure group and compensated hypertrophy group. The number of apoptotic myocardial cells in congestive heart failure group increased significantly in comparison with that in compensated hypertrophy group (P<0 05). There was significant difference (P<0 05) in positive index (PI) of Fas protein, but no significant differen ce (P>0 05) in PI of FasL protein between sham-operated group and compensa ted hypertrophy group. When the congestive heart failure occurred, positive index (PI) of Fas and FasL protein in myocardial cells were increased very significantly (P<0 05) than those in myocardium of Wistar\|kyoto rats with compensated hypertrophy. The expression of Fas gene in myocardium of rats with congestive heart failure was significantly higher than that in sham-operated group and compensated hypertrophy group (P<0 05). Conclusions Incre ased myocardial apoptosis may be the important mechanism by which the transition from compensated hypertrophy to heart failure. Changes of myocardial apoptosis and the expression of Fas and FasL gene s suggest that apoptosis and Fas/FasL system are involved in the experimental congestive heart failure rats.