Oxidative stress on mitochondria and cell membrane of cultured rat hepatocytes and perfused liver exposed to ethanol.
OBJECTIVE
The precise pathogenic significance of oxidative injury in the evolution of alcohol-induced liver disease is still obscure. The present report was designed to investigate whether ethanol alters the production of active oxidants and biological activities of hepatocytes.


METHODS
The following parameters in rat hepatocytes were investigated by using fluorescence probes in vitro and ex vivo: (1) mitochondrial membrane potential and membrane permeability transition, (2) oxygen radicals generation, (3) membrane barrier function, and (4) glutathione level.


RESULTS
Ethanol (50 mmol/L) increased oxidative stress in hepatocytes and subsequently induced an increased mitochondrial permeability transition and a decreased membrane potential. These ethanol-induced alterations were attenuated by an inhibitor of alcohol dehydrogenase and an intracellular oxidant scavenger, whereas they were enhanced by diethyl maleic acid, a glutathione depletor. Ethanol plus diethyl maleic acid but not ethanol alone increased the number of hepatocytes with membrane barrier dysfunction. A continuous infusion of ethanol (50 mmol/L) increased oxidative stress and decreased mitochondrial membrane potential in the pericentral area of isolated perfused rat liver.


CONCLUSIONS
Active oxidants generated during ethanol metabolism increase mitochondrial permeability transition and modulate mitochondrial energy synthesis in hepatocytes. Reduction of glutathione level enhances mitochondrial dysfunction and impairs membrane barrier function of hepatocytes.
Kurose
I
I
Department of Internal Medicine, School of Medicine, Keio University, Shinju-ku, Tokyo, Japan.
Higuchi
H
H
Kato
S
S
Miura
S
S
Watanabe
N
N
Kamegaya
Y
Y
Tomita
K
K
Takaishi
M
M
Horie
Y
Y
Fukuda
M
M
Mizukami
K
K
Ishii
H
H
D000426:Alcohol Dehydrogenase / Q000037:antagonists & inhibitors; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D000431:Ethanol / Q000494:pharmacology*; D000077604:Fomepizole; D016166:Free Radical Scavengers; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism* / Q000502:physiology; D018384:Oxidative Stress; D010477:Perfusion; D010539:Permeability; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology
D016166:Free Radical Scavengers; D011720:Pyrazoles; D000431:Ethanol; D000077604:Fomepizole; C038983:1,3-dimethylthiourea; D000426:Alcohol Dehydrogenase; D013890:Thiourea