乙醇诱导的大鼠肝脏细胞内硫醇区室化和蛋白质氧化还原状态的变化：牛磺熊去氧胆酸的作用

Ethanol-induced changes of intracellular thiol compartmentation and protein redox status in the rat liver: effect of tauroursodeoxycholate.

作者信息

Vendemiale G, Grattagliano I, Signorile A, Altomare E

机构信息

Department of Internal and Occupational Medicine, University of Bari, Italy.

出版信息

J Hepatol. 1998 Jan;28(1):46-53. doi: 10.1016/s0168-8278(98)80201-8.

DOI:10.1016/s0168-8278(98)80201-8

PMID:9537863

Abstract

BACKGROUND/AIMS: Ethanol impairs cellular antioxidant defense and protein metabolism. Hydrophilic bile acids are protective against ethanol-induced cytotoxicity. This study investigated the compartmentation of intracellular thiol and protein redox status after acute ethanol intoxication in the liver and the effect of tauroursodeoxycholate pretreatment.

METHODS

The concentrations of total glutathione, glutathione bound to proteins, sulfhydryl proteins, carbonyl proteins and malondialdehyde were measured in hepatic cytosol, mitochondria and nuclei after oral administration of 25% ethanol (4 g/kg) or isocaloric carbohydrate solution to rats. The metabolisms of ethanol and acetaldehyde were investigated by giving 4-methylpyrazole (1 mmol/kg i.p.) or cyanamide (15 mg/kg i.p.) 1 h prior to ethanol ingestion. One group of rats received tauroursodeoxycholate (12 mg/kg p.os) 1 h before ethanol ingestion.

RESULTS

Ethanol significantly decreased the glutathione concentrations. Significant increases in glutathione bound to proteins, carbonyl protein and malondialdehyde concentrations were also noted, especially at the mitochondrial level. Enhanced carbonyl protein formation was also observed (p < 0.01). The inhibition of acetaldehyde metabolism, but not ethanol metabolism, exaggerated the alterations produced by ethanol. Pretreatment with tauroursodeoxycholate significantly reduced lipid and protein oxidation, particularly in mitochondria. By contrast, no changes were observed in glutathione content and compartmentation.

CONCLUSIONS

Ethanol intoxication differentially impairs thiol and protein redox status in the subcellular fractions of rat liver. These alterations seem dependent on acetaldehyde rather than ethanol. Tauroursodeoxycholate administration protects proteins and lipids from ethanol-induced oxidative damage without influencing the glutathione content and compartmentation.

摘要

背景/目的：乙醇会损害细胞抗氧化防御和蛋白质代谢。亲水性胆汁酸可预防乙醇诱导的细胞毒性。本研究调查了急性乙醇中毒后肝脏细胞内巯基和蛋白质氧化还原状态的区室化情况以及牛磺熊去氧胆酸预处理的影响。

方法

给大鼠口服25%乙醇（4 g/kg）或等热量碳水化合物溶液后，测定肝细胞质、线粒体和细胞核中总谷胱甘肽、与蛋白质结合的谷胱甘肽、巯基蛋白、羰基蛋白和丙二醛的浓度。在摄入乙醇前1小时给予4-甲基吡唑（1 mmol/kg腹腔注射）或氰胺（15 mg/kg腹腔注射），研究乙醇和乙醛的代谢。一组大鼠在摄入乙醇前1小时接受牛磺熊去氧胆酸（12 mg/kg口服）。

结果

乙醇显著降低了谷胱甘肽浓度。还注意到与蛋白质结合的谷胱甘肽、羰基蛋白和丙二醛浓度显著增加，尤其是在线粒体水平。还观察到羰基蛋白形成增强（p < 0.01）。乙醛代谢的抑制而非乙醇代谢的抑制加剧了乙醇产生的改变。牛磺熊去氧胆酸预处理显著降低了脂质和蛋白质氧化，特别是在线粒体中。相比之下，谷胱甘肽含量和区室化未观察到变化。