肥胖对家兔心房肌组织结构和电生理特性的影响

目的:探讨肥胖对家兔心房肌组织结构和电生理特性的影响,为进一步了解肥胖影响房颤(AF)易感性的相关机制和AF的早期干预提供实验依据。方法:将30只家兔随机分为正常组、肥胖组和肥胖+他汀药物组,雌雄各半,每组10只。肥胖组给予高脂饲料,造模成功后,采用Langendorff离体灌注法对3组家兔分别进行离体心脏灌注。采用心脏电生理刺激仪监测心房肌的电生理特性参数:肥胖组家兔房内传导时间(HRA-HIS)、心房有效不应期(AERP)、窦房结恢复时间(SNRT)、校正后窦房结恢复时间(CSNRT)。剪取部分心耳组织,经MASSON染色观察心房肌纤维化的程度。采用TUNEL法测定心房肌细胞的凋亡率。结果:与正常组相比,肥胖组家兔HRAHIS、AERP、SNRT和CSNRT等电生理参数均出现不同程度的延长,并导致AERP频率自适应性降低。与肥胖组比较,肥胖+他汀药物组的心肌基质胶原纤维显著减少(P0.05),心肌胶原容积分数(CVF)显著减低(P0.01),心肌细胞凋亡率(%)明显降低(P0.01)。结论:肥胖可引起家兔心房肌组织结构与电生理基质改变,利于AF的发生与维持,而应用他汀类药物干预后,这些改变有所改善。

IInfluence of obesity on rabbit atrial muscle tissue structure and electrical physiological characteristics

AIM:To explore the influence of obesity on rabbit atrial muscle tissue structure and electrical physiological characteristics and to better understand the mechanism of atrial fibrillation (AF) susceptibility induced by obesity and to provide an experimental basis for early intervention AF. METHODS: Thirty rabbits were randomly divided into three groups: normal group, obesity group and obesity statin group, with ten rabbits in each group. After the successful establishment of the obesity model, Langendorff perfusion in vitro was used for rabbit heart perfusion in vitro. The cardiac electrophysiological stimulator was then used to detect the electrical physiological characteristic parameters including atrium room conduction time (HRA-HIS), atrial effective refractory period (AERP), sinoatrial node recovery time (SNRT), and corrected sinoatrial node recovery time (CSNRT). After shearing part of the rabbit auricle tissue, atrial muscle fibrosis was observed using Masson stain and atrial muscle cell apoptosis was detect by TUNEL. RESULTS: The electrical physiological parameters including HRA-HIS, AERP, SNRT and CSNRT were all extended to some degree and AERP frequency adaptability significantly reduced in obesity group. The myocardial matrix collagen fiber and CVF obviously decreased, whereas cardiomyocyte apoptosis rate significantly increased in the obesity group compared with those in the obesity statin group (all P<0.05). CONCLUSION: Obesity can change the rabbit atrial muscle tissue structure and electrical physiological characteristics, which is propitious to the occurrence and maintenance of AF.