心肌肥厚和心力衰竭时左心室收缩力及钙瞬变的变化  

Changes of the Contraction and Calcium Transients in Myocytes of Left Ventricle in Patients with Cardiac Hypertrophy and Heart Failure

作　　者：李行[1] 杨梓琪[1] 张光宇[1] 常旦琪 钱成[1] 王扬淦[1] 

机构地区：[1]武汉大学中南医院心内科,湖北武汉430071

出　　处：《武汉大学学报（医学版）》2017年第5期699-703,共5页Medical Journal of Wuhan University

摘　　要：目的:研究心肌肥厚和心力衰竭时左心室收缩力及钙瞬变的变化。方法:采用主动脉缩窄术构建压力负荷型心衰小鼠模型及心肌肥厚小鼠模型,小动物超声机测量小鼠心室壁厚度及射血分数,Langendorff灌流术分离小鼠左心室心肌细胞,高速CCD摄像机系统和双激发荧光倍增系统同步测量左心室心肌细胞肌小节收缩舒张功能和胞内钙瞬变。结果:与假手术组相比,肥厚小鼠心室壁明显增厚,胞质基础钙浓度、钙瞬变振幅增高,钙瞬变达峰时间、恢复时间和肌小节舒张时间明显延长,肌小节初长度缩短;心衰组小鼠心腔扩大,射血分数(EF)、钙瞬变峰值、峰高、达峰时间及胞质内钙恢复的速度明显下降,肌小节初始长度显著缩短,收缩幅度下降,静息期基础钙浓度显著上升,收缩及舒张时间均明显延长。结论:在心力衰竭的发展过程中,随着心脏结构的改变,心肌细胞对胞内钙的释放和回收能力均下降,使单个心肌细胞收缩无力、舒张时间延长,进而影响整个心脏的收缩舒张功能。改善心肌细胞钙循环可能在缓解心衰患者临床症状和改善预后方面起到关键作用。Objective：To study the alterations of contraction and calcium transients of left ventricular myocytes in mice with cardiac hypertrophy and heart failure.Methods：Cardiac hypertrophy and heart failure in C57/BL6 mice were induced by severe thoracic aortic banding（sTAB）.The ventricular wall thickness of mice were measured by using ultrasound.Myocytes were isolated from mice by Langendorff perfusion.Sarcomere contraction and Ca2＋transient were recorded simultaneously using a high speed CCD video camera and a dual excitation fluorescence photomultiplier system.Results：Compared with normal mice,ultrasonic examination of cardiac hypertrophic mice showed significantly increased left ventricular wall thickness.Calcium transient manifested remarkable increases in baseline calcium,peak height of calcium,time to peak,and tau value,with a significant decrease in original sarcomere length.Compared with normal mice,ultrasonic examination showed significantly expanded left ventricular internal diameter（LVID）and decreased ejection fraction（EF）in heart failure mice.Calcium transient manifested substantial increase in baseline calcium,while the peak and peak height of calcium,time to peak,tau value,and the original sarcomere length reduced.Conclusion：During the course of heart failure,the re-lease and recycling of intracellular calcium were both decreased in cardiac myocytes along with the development of cardiac remodeling,which weakens the contraction and prolongs the relaxation time in single cardiac myocyte,thus affecting the systolic and diastolic function of the whole heart.The improvement of myocardial calcium cycling may play a key role in relieving clinical symptoms and improving prognosis in patients with heart failure.

关 键 词：心肌肥厚 心力衰竭 钙瞬变 肌小节收缩 

分 类 号：R541.61[医药卫生—心血管疾病]