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腹主动脉缩窄20周大鼠心肌细胞的自噬通量

崔龙彪, 圣娟娟, 王云英, 余志斌

第四军医大学航空航天医学教育部重点实验室；第四军医大学航空航天生理学教研室，西安 710032

摘要

长期心脏压力超负荷致心衰心肌的自噬水平明显增高，这种自噬增强是对心肌的保护机制，还是诱导代偿性肥大心肌转向心力衰竭的因素，是尚未阐明的问题。本研究旨在明确腹主动脉缩窄(transverse abdominal aortic constriction, TAC) 20周大鼠心肌细胞的自噬通量。将禁食大鼠作为阳性对照，采用超声心动图检测心脏结构和功能变化，用免疫荧光组织化学染色与Western blot检测自噬相关生物分子指标，从而验证心肌细胞自噬通量检测方法的可靠性，然后观测TAC 20周大鼠心肌细胞自噬通量的改变。结果显示，禁食对大鼠心脏室间隔与左心室后壁厚度等结构指标未产生显著性影响，而禁食3 d大鼠心率、舒张末期左心室内径、左心室缩短率、射血分数及二尖瓣血流速度降低。禁食3 d大鼠心肌细胞胞浆LC3与cathepsin D表达明显增加，而ubiquitin与complement 9染色未发生明显改变，表明心肌自噬通量增加。和假手术组相比，TAC 20周大鼠心肌组织LC3、cathepsin D、ubiquitin与complement 9免疫荧光组织化学染色未改变，心肌LC3、cathepsin D与p62蛋白表达水平亦未改变。以上结果表明，在TAC大鼠心肌肥大中后期，心肌细胞自噬通量并未发生明显改变，提示此时心肌细胞肥大产生的抑制自噬作用与压力负荷应激引起的激活自噬作用可能达到平衡状态。

关键词： 自噬; 禁食; 心肌肥大; 心力衰竭

分类号：R337.2

[Autophagic flux of cardiomyocytes from 20-week transverse abdominal aortic constriction rats.] [Article in Chinese]

CUI Long-Biao, Sheng Juan-Juan, WANG Yun-Ying, YU Zhi-Bin

Key Laboratory of Aerospace Medicine, Ministry of Education；Department of Aerospace Physiology, Fourth Military Medical University 169#Changlexi road, Xi'an 710032, China

Abstract

Cardiac autophagy dramatically increases in heart failure induced by sustained pressure overload. However, it has not yet been addressed if enhanced autophagy plays a role in protecting myocardium or mediating progression from compensative hypertrophy to heart failure. The aim of the present study was to detect autophagic flux of cardiomyocytes from 20-week transverse abdominal aortic constriction (TAC) rats. Fasting rats were used as the positive control for detecting cardiac autophagy. Echocardiography was applied to find the changes of cardiac structure and function. Immunofluorescent histochemistry and Western blot were used to analyze the related biomolecular indexes reflecting cardiac autophagic flux. After the previous methods for detecting cardiac autophagy were confirmed, the autophagic flux in cardiomyocytes of rats subjected to 20-week TAC was examined. The results showed that fasting had no obvious influence on parameters of cardiac structure in rats, including interventricular septal wall thickness and left ventricle posterior wall thickness, but heart rate, diastolic left ventricle internal dimension, fractional shortening of left ventricle dimension, ejection fraction and mitral inflow velocity decreased in rats after fasting for 3 d. Meanwhile, positively stained particles of LC3 and cathepsin D, but not ubiquitin and complement 9, distributed within cardiomyocytes of 3-day fasting rats, indicating augmented autophagic flux. Compared with sham rats, 20-week TAC rats did not show any changes of LC3, cathepsin D, ubiquitin and complement 9 in myocardium detected by immunofluorescent histochemistry. In addition, protein levels of LC3, cathepsin D and p62 in myocardium of TAC rats did not changed. These results reveal the unchanged autophagic flux in cardiomyocytes at middle or late phase of cardiac hypertrophy in TAC rats, implying a balance between inhibition of hypertrophy and activation of pressure load stress on autophagy.

Key words: autophagy; fasting; cardiac hypertrophy; heart failure

收稿日期：2012-08-25　　录用日期：2012-12-13

通讯作者：余志斌　　E-mail: yuzhib@fmmu.edu.cn

引用本文：

崔龙彪, 圣娟娟, 王云英, 余志斌. 腹主动脉缩窄20周大鼠心肌细胞的自噬通量[J]. 生理学报 2013; 65 (3): 301-308.

CUI Long-Biao, Sheng Juan-Juan, WANG Yun-Ying, YU Zhi-Bin. [Autophagic flux of cardiomyocytes from 20-week transverse abdominal aortic constriction rats.] [Article in Chinese]. Acta Physiol Sin 2013; 65 (3): 301-308 (in Chinese with English abstract).