在培养的鸡心肌细胞中，乙醇暴露会损害线粒体基因表达。

Mitochondrial gene expression is impaired by ethanol exposure in cultured chick cardiac myocytes.

作者信息

Kennedy J M

机构信息

University of Illinois at Chicago, Department of Physiology and Biophysics 60612-7342, USA.

出版信息

Cardiovasc Res. 1998 Jan;37(1):141-50. doi: 10.1016/s0008-6363(97)00198-3.

DOI:10.1016/s0008-6363(97)00198-3

PMID:9539868

Abstract

OBJECTIVE

A depression in cytochrome c oxidase (COX) activity occurs following chronic embryonic ethanol exposure in vivo. The aim of this study was to examine the effect of chronic ethanol exposure on COX activity in isolated cardiac cells maintained in vitro. Additionally, the mechanism by which ethanol produces an impairment in COX activity was evaluated by examining mitochondrial gene expression.

METHODS

Spontaneously beating cardiac myocyte cultures were established from 10-day embryonic chick hearts. Various concentrations of ethanol (0-250 mM) were introduced at the time of plating and cells were harvested over 7 days. COX activity was determined in myocyte homogenates. The levels of nuclear-encoded (COXIV) and mitochondrial-encoded (COXII) subunit proteins were measured by Western blotting. Relative levels of mitochondrial DNA and the mitochondrially-encoded COXIII mRNA were determined by Southern and Northern blotting.

RESULTS

A consistent decrease in COX activity in ethanol-exposed cardiac myocytes of approximately 30% was observed with an ethanol concentration of 25 mM. Increasing the ethanol concentration to 250 mM produced only a minor enhancement of this effect, while severely decreasing cellular viability. The content of the mitochondrially-encoded COXII subunit was reduced by ethanol exposure, while that of the nuclear-encoded COXIV subunit was unchanged. The content of the mitochondrially-encoded COXIII mRNA was unchanged by ethanol exposure. However, prolonged ethanol exposure produced an increase in mitochondrial DNA levels in cardiac myocytes.

CONCLUSIONS

Ethanol exposure of cardiac myocytes produces deficits in COX activity in the absence of systemic variables, indicating that ethanol has a direct effect on cardiac mitochondria. The ethanol-induced decrease in COX activity is correlated with a specific decrease in at least one mitochondrially-encoded gene product, COXII. No changes were observed in the level of the nuclear-encoded COXIV subunit, indicating that expression of this nuclear-encoded gene is not impaired by ethanol exposure.

摘要

目的

体内长期胚胎乙醇暴露后细胞色素c氧化酶（COX）活性会降低。本研究的目的是检测慢性乙醇暴露对体外培养的分离心肌细胞中COX活性的影响。此外，通过检测线粒体基因表达来评估乙醇导致COX活性受损的机制。

方法

从10日龄胚胎鸡心脏建立自发搏动的心肌细胞培养物。接种时加入不同浓度的乙醇（0 - 250 mM），并在7天内收获细胞。测定心肌细胞匀浆中的COX活性。通过蛋白质印迹法测量核编码（COXIV）和线粒体编码（COXII）亚基蛋白的水平。通过Southern和Northern印迹法测定线粒体DNA和线粒体编码的COXIII mRNA的相对水平。

结果

在乙醇浓度为25 mM时，观察到乙醇暴露的心肌细胞中COX活性持续降低约30%。将乙醇浓度增加到250 mM仅使这种效应略有增强，同时严重降低细胞活力。乙醇暴露使线粒体编码的COXII亚基含量降低，而核编码的COXIV亚基含量未改变。乙醇暴露未改变线粒体编码的COXIII mRNA的含量。然而，长期乙醇暴露使心肌细胞中的线粒体DNA水平增加。