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心肌细胞肥大程度与收缩功能的变化

陈焱, 王云英，张蓝宁，常 惠，张 琳，宋 振，余志斌*

第四军医大学航空航天生理学教研室，西安 710032

摘要

为探明压力超负荷性心脏肥厚转向心力衰竭过程中，心肌细胞形态与收缩功能的动态变化，本研究建立腹主动 脉缩窄(transverse abdominal aortic constriction, TAC)高血压大鼠模型，观测在TAC 后1、8、16 与20 周时，单个心肌细 胞形态与无负荷缩短幅值的变化。结果显示：TAC 手术后大鼠体重增长明显慢于同步对照假手术组，且用左心室质量与 体重比不能准确衡量心肌肥厚程度，而用胶原酶分离心肌细胞后，直接测量单个心肌细胞长度与宽度的结果显示，TAC 术后8、16 和20 周时，心肌细胞长度、宽度和表面面积均较同步对照组显著增加，较好地反映了心肌细胞的肥大程度。 TAC 心肌细胞面积的增长速率在早期至中期较快，后期明显下降。肥大心肌细胞的长度与宽度在TAC 后8 周开始明显增 加，但肌节长度保持不变，而肌节数量呈显著性增加。与同步对照组相比，单个心肌细胞的无负荷缩短幅值在1 周TAC 组明显增加，8 周组无统计学差别，16 与20 周组则显著降低。上述结果提示：肥大心肌细胞收缩功能降低与其细胞内分 子功能改变有关。

关键词： 压力超负荷; 高血压; 心肌细胞; 肌节; 收缩功能

分类号：Q46

[Cardiac hypertrophy and changes in contractile function of cardiomyocyte.] [Ariticle in Chinese]

CHEN Yan, WANG Yun-Ying, ZHANG Lan Ning, CHANG Hui, ZHANG Lin, SONG Zhen, YU Zhi-Bin*

Department of Aerospace Physiology, the Fourth Military Medical University, Xi’an 710032, China

Abstract

To investigate the cellular mechanisms of pressure-overload cardiac hypertrophy transition to heart failure, we observed time course of changes in morphology and contractile function of cardiomyocytes in transverse abdominal aortic constriction (TAC) rats. Since TAC rats suffered higher stress, body weight had a slower growth rate compared with that of synchronous control rats. Therefore, the left ventricular to body weight ratio produced experimental bias to evaluate the degree of cardiac hypertrophy. Length and width of collagenase-isolated cardiomyocyte were directly measured. Length, width and calculated surface area of cardiomyocyte showed a progressive increase in 8-, 16-, and 20-week TAC rats. The increasing rate of surface area in cardiomyocytes was higher at the middle stage of TAC (from the eighth to sixteenth week). Due to the constraint of fibrosis formation, the increasing rate of surface area in cardiomyocytes was slower at the late stage of TAC (from the sixteenth to twentieth week). The sarcomere length of cardiomyocytes was unchanged, whereas sarcomere numbers were significantly increased in 8-, 16-, and 20-week TAC rats. Shortening amplitude of unloaded contraction in single cardiomyocyte was significantly enhanced in 1-week TAC rats, but not altered in 8-week TAC rats compared with that in the synchronous control rats. On the contrary, unloaded shortening amplitude of single cardiomyocyte was significantly reduced in 16- and 20-week TAC rats. The above results suggest that the reduced shortening amplitude may be associated with intrinsic molecular alterations in hypertrophied cardiomyocytes.

Key words: pressure-overload; hypertension; myocytes; cardiac; sarcomeres

收稿日期：2010-07-30　　录用日期：2010-09-07

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引用本文：

陈焱, 王云英，张蓝宁，常 惠，张 琳，宋 振，余志斌*. 心肌细胞肥大程度与收缩功能的变化[J]. 生理学报 2010; 62 (6): 517-523.

CHEN Yan, WANG Yun-Ying, ZHANG Lan Ning, CHANG Hui, ZHANG Lin, SONG Zhen, YU Zhi-Bin*. [Cardiac hypertrophy and changes in contractile function of cardiomyocyte.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (6): 517-523 (in Chinese with English abstract).