Copyright ©ERS Journals Ltd 2007 Resistance of quiescent and proliferating airway epithelial cells to H2O2 challenge1 Dept of Analytical Biochemistry, University Centre for Pharmacy, University of Groningen, and 2 Laboratory for Allergology and Pulmonology, and 3 Groningen University Institute for Drug Exploration, University Medical Centre Groningen, Groningen, The Netherlands. CORRESPONDENCE: H. F. Kauffman, Groningen University Institute for Drug Exploration (GUIDE), A. Deusinglaan 1, 9713 AV Groningen, The Netherlands. Fax: 31 503632612. E-mail: Henk.Kauffman{at}inter.nl.net Keywords: Apoptosis, chronic obstructive pulmonary disease, epithelial cells, necrosis, oxidative stress, thiols
Received: July 17, 2006
Alveolar epithelial cell injury and recovery are important in the pathogenesis of oxidant-induced lung damage. The alveolar cell line A549 was used to study responses of proliferating and quiescent cells in culture to time- and dose-dependent hydrogen peroxide (H2O2) challenges.
Recovery was monitored after 24 h of incubation in fresh medium with 10% serum. The adherent cells were counted and the resistance and recovery of the attached cells was assessed by appearance, by measuring the number of viable, apoptotic and necrotic cells using fluorescent-activated cell sorting, and by determining the intracellular free thiol content.
A549 cells recovered from a 1-h challenge with up to 1 mM H2O2 but could not sustain a more prolonged challenge (6 or 24 h) with 0.5 mM or 1.0 mM H2O2. These more severe conditions resulted in: loss of cells by detachment from the plate surface; reduced numbers of viable cells primarily due to necrosis; and a strong reduction of the intracellular free thiol content.
Quiescent cells proved to be more sensitive to oxidative stress than proliferating cells. Intracellular free thiol levels apparently play a decisive role in cell survival, preferentially protecting proliferating cells.
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