Sites and mechanisms of low-level oxidative stress in cultured cells.
Oxidative stress is involved in a multitude of pathological conditions. In the present study, we investigated the cellular targets and the mechanisms of low-level oxidative stress in a Chinese Hamster Ovary cell culture. Oxidative stress was induced either by continuous enzymatic production of superoxide or by bolus addition of hydrogen peroxide (H2O2). Low-level oxidative stress irreversibly impaired the reproductive capacity of the cells in the absence of damage to membrane integrity or energy metabolism. Cells were protected by catalase but not by superoxide dismutase, indicating that H2O2, not superoxide, was the causative agent of cell damage. Nitroxide spin labels decreased hydroxyl radical (.OH) formation and protected cells from the oxidative stress. The differing membrane permeabilities of these spin labels suggest that the damage is localized on the cell surface. Oxidative stress to DNA and RNA was not significant, as shown by levels of guanine hydroxylation products. A mechanism is proposed whereby low-level oxidative stress acts at the cell surface to cause impairment of cell reproduction.
Gelvan
D
D
Department of Human Nutrition and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Israel.
Moreno
V
V
Clopton
D A
DA
Chen
Q
Q
Saltman
P
P
D000818:Animals; D016466:CHO Cells; D002374:Catalase / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects*; D006224:Cricetinae; D003497:Cyclic N-Oxides; D004305:Dose-Response Relationship, Drug; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000378:metabolism; D007770:L-Lactate Dehydrogenase; D018384:Oxidative Stress; D013113:Spin Labels; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*
D003497:Cyclic N-Oxides; D013113:Spin Labels; D013481:Superoxides; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D013482:Superoxide Dismutase; C003959:TEMPO