摘要
目的比较青年与老年小鼠在程序性电刺激下诱发室性心律失常的易感性,为后续老龄化相关心律失常研究奠定基础。方法分别对C57BL/6J青年小鼠(8~12周龄)和老年小鼠(16+月龄)做体表心电图和程序性电刺激,观察其室性心动过速(ventricular tachycardia,VT)的发生情况。通过小鼠心脏超声检测相关心功能指标,并用光学标测方法测量心室肌电位和Ca^(2+)变化。结果与青年小鼠相比,老年小鼠的R-R间期延长,电刺激和ISO诱导VT发生率增加,差异有统计学意义(P<0.01)。心脏超声提示,与青年小鼠相比,老年小鼠的射血分数(ejection fraction,EF)降低、缩短分数(fractional shortening,FS)降低、左室舒张期末后壁厚度(end-diastolic left ventricular posterior wall thickness,LVPWd)增加,差异均具有统计学意义(P<0.01)。组织形态学显示,与青年小鼠相比,老年小鼠心重胫骨长度比值增大、心肌细胞横截面积增大、胶原容积增加,差异均具有统计学意义(P<0.001)。光学标测结果显示老年小鼠动作电位及钙瞬变时程延长,差异具有统计学意义(P<0.05),在电刺激及ISO刺激下老年小鼠出现明显的电传导折返,提示老年小鼠心脏电传导异常,易发心律失常。结论与青年小鼠相比,老年小鼠心脏组织形态改变和心功能下降,尤其是增龄导致的心脏电生理的改变,增加了老年小鼠心律失常的易感性。
Objective The aim of this study was to compare susceptibility differences in ventricular arrhythmias induced by pro⁃grammed electrical stimulation between young and old mice,and to lay a foundation for subsequent research in this area.Methods C57BL/6J young mice(8~12 weeks old)and old mice(16+months old)were included in this study.ECG and programmed electrical stimulation were used to observe the occurrence of ventricular tachycardia(VT).Cardiac function indicators were detected by echocar⁃diography,while membrane voltage and Ca2+were also measured by optical mapping.Results Compared with young mice,old mice had a significantly prolonged R-R interval and increased occurrence rate of VT induced by electrical stimulation and ISO(P<0.01).Echo⁃cardiography results showed that compared with young mice,old mice had decreased ejection fraction(EF)and fractional shortening(FS)(P<0.01),but increased end-diastolic left ventricular posterior wall thickness(LVPWd)(P<0.01).Histomorphology results demonstrated that compared with young mice,old mice had an increased ratio of heart weight to tibia length,an enlarged cross-sectional area of cardiomyocytes,and an increased collagen volume(P<0.001).Optical mapping results showed that the action potential dura⁃tion(APD)and Ca^(2+)transient duration(CaTD)of old mice were prolonged with statistically significant differences(P<0.05),and that old mice also exhibited obvious electrical reentrant under electrical stimulation and ISO stimulation,indicating that aging increased ab⁃normal electrical conduction and susceptibility to arrhythmia.Conclusion Compared to young mice,aged mice exhibited morphologi⁃cal changes in cardiac tissue and a decline in cardiac function,particularly alterations in cardiac electrophysiology resulting from aging,which increased susceptibility to cardiac arrhythmias in aged mice.
作者
罗弦
刘竹
李阳鹏
胡剑
欧贤红
谭晓秋
陈唐葶
LUO Xian;LIU Zhu;LI YangpengHU Jian;OU Xianhong;TAN Xiaoqiu;CHEN Tangting(Key Laboratory of Medical Electrophysiology of Ministry of Education,Medical Electrophysiology Key Laboratory of Sichuan Prov-ince,Institute of Cardiovascular Research,Southwest Medical University,Luzhou 646000,China;School of Basic Medical Science,Southwest Medical University,Luzhou 646000,China)
出处
《西南医科大学学报》
2023年第4期308-313,共6页
Journal of Southwest Medical University
基金
国家自然科学基金(81900277)
四川省自然科学基金(2022NSFSC1602)
四川省科技计划资助项目(2022YFS0607)。
