Response of the antioxidant defense system to tert-butyl hydroperoxide and hydrogen peroxide in a human hepatoma cell line (HepG2).
The aim of this work was to investigate the response of the antioxidant defense system to two oxidative stressors, hydrogen peroxide and tert-butyl hydroperoxide, in HepG2 cells in culture. The parameters evaluated included enzyme activity and gene expression of superoxide dismutase, catalase, glutathione peroxidase, and activity of glutathione reductase. Besides, markers of the cell damage and oxidative stress evoked by the stressors such as cell viability, intracellular reactive oxygen species generation, malondialdehyde levels, and reduced glutathione concentration were evaluated. Both stressors, hydrogen peroxide and tert-butyl hydroperoxide, enhanced cell damage and reactive oxygen species generation at doses above 50 microM. The concentration of reduced glutathione decreased, and levels of malondialdehyde and activity of the antioxidant enzymes consistently increased only when HepG2 cells were treated with tert-butyl hydroperoxide but not when hydrogen peroxide was used. A slight increase in the gene expression of Cu/Zn superoxide dismutase and catalase with 500 microM tert-butyl hydroperoxide and of catalase with 200 microM hydrogen peroxide was observed. The response of the components of the antioxidant defense system evaluated in this study indicates that tert-butyl hydroperoxide evokes a consistent cellular stress in HepG2.
Alía
Mario
M
Departmento de Metabolismo y Nutrición, Instituto del Frío, Consejo Superior de Investigaciones Científicas, José Antonio Novais 10, Ciudad Universitaria, 28040 Madrid, Spain.
Ramos
Sonia
S
Mateos
Raquel
R
Bravo
Laura
L
Goya
Luis
L
D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D008113:Liver Neoplasms / Q000378:metabolism*; D016877:Oxidants / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D020122:tert-Butylhydroperoxide / Q000633:toxicity*
D016877:Oxidants; D017382:Reactive Oxygen Species; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide