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目的 研究在心房颤动(简称房颤)时左房肌钙激活中性蛋白酶(calpain1、calpain2)、钙蛋白酶抑素(calG pastatin)与LG型电压依赖钙通道a1c亚基(LVDCCa1c)的表达变化,探讨房颤发生、维持的分子机制.方法 健康杂种犬28只,雌雄不限.根据年龄大小、节律随机分为成年窦律组、老年窦律组、成年房颤组、老年房颤组,每组各7只.各房颤组通过持续快速心房起搏建立持续性房颤犬模型.取100g左房组织,用实时荧光定量聚合酶反应(Realtime PCR)和蛋白免疫印迹(Westernblot)方法检测犬calpain1、calpain2、calpastatin及LVDCCa1c在m RNA和蛋白质表达水平变化.应用光镜、电镜检测细胞病理及超微结构改变,用DNA断裂的原位末端标记法(TUNEL法)检测细胞凋亡情况.结果 与成年组比较,老年组LVDCCa1c在m RNA和蛋白质表达水平显著地降低(P<0.05);同年龄组内与相应窦律组比较,房颤组LVDCCa1c表达显著地降低(P<0.05),而calpain1表达显著地增高(P<0.05),尤其是老年房颤组增高最为明显,老年房颤组LVDCCa1c与calpain1在蛋白质表达水平呈现负相关(r=-0.583,P=0.019).与成年和窦律组比较,老年和房颤组犬心肌纤维化程度加重、细胞超微结构改变(肌原纤维退化,线粒体变性,核固缩)及凋亡指数增加.结论 钙激活中性蛋白酶特异性生物活性随年龄及节律改变,可能是心房重构的分子机制之一.
Objective To investigate the expression of calpain1, calG pastatin and LG-type voltage-dependent calcium channel a1c subunit (LVDCCa1c) in atrial fibrillation (AF) To investigate the molecular mechanism of occurrence and maintenance of atrial fibrillation.Methods 28 healthy mongrel dogs were randomly divided into adult sinus rhythm group, elderly sinus rhythm group, adult AF group and elderly AF group according to the age and rhythm. Group A. The atrial fibrillation group was established by continuous rapid atrial pacing in a continuous atrial fibrillation model.We take 100g left atrium tissue and detect the dogs by Realtime PCR and Western blotting The expression of calpain1, calpain2, calpastatin and LVDCCa1c in m RNA and protein were detected by light microscopy, electron microscopy, cell apoptosis and ultrastructure changes were detected by DNA nick end labeling (TUNEL) Compared with the adult group, the expression of LVDCCa1c in the aged group was significantly lower than that in the sinus rhythm group (P <0.05), while the expression of LVDCCa1c in the aged group was significantly decreased (P <0.05) The expression of calpain1 was significantly increased (P <0.05), especially in elderly patients with atrial fibrillation. The expression of LVDCCa1c and calpain1 was negatively correlated with the protein expression in elderly patients with atrial fibrillation (r = -0.583, P = 0.019) In the law group, myocardial fibrosis was more severe in the aged and atrial fibrillation group, and ultrastructural changes (myofibrillar degeneration, mitochondrial degeneration, nuclear pyknosis) and apoptosis index were increased.Conclusion The specific bioactivity of calcium-activated neutral proteinase Changes with age and rhythm may be one of the molecular mechanisms of atrial remodeling.