Abstract
[Aim] The pulmonary toxicity of high concentration of oxygen during mechanical ventilation relates to reactive oxygen species (ROS). Hydrogen gas (H2) has potential as eliminating highly reactive ROS. We therefore expected that H2 could reduce the adverse effects of the oxygen exposure. The aim of the present study was to determine the protective effects of H2 against various oxidative stresses on epithelial cells in vitro.
[Methods] Human alveolar epithelial cells (A549) were incubated with antimycin A which enhances the generation of superoxide anions (O2-) in mitochondria, with menadione which exogenously generates O2- and H2O2 in the cells, or with Cu+ (converted from Cu2+ by ascorbic acid) which exogenously generates hydroxyl radical by the Fenton reaction with added Cu+ and endogenous H2O2. The viability of the cells as well as the levels of O2- and highly reactive ROS in the cells was evaluated with or without 2% H2.
[Results] The viability of the cells incubated with menadione or Cu+ decreased or did not change in the presence of H2, respectively, while that with antimycin A significantly increased in the presence of H2 (n=12, P<0.01). The production of O2- induced by antimycin A significantly decreased with the addition of H2 (n=11, P<0.01), while highly reactive ROS induced by menadione significantly increased in the cells incubated with H2 (n=5, P<0.01).
[Conclusions] H2 protects alveolar epithelial cells against injury induced by antimycin A probably due to the decrease in the production of O2- in mitochondria, while H2 cannot act protective against ROS induced by menadione or the Fenton reaction, meaning that H2 cannot overcome the effects of exogenously provided ROS.
- © 2012 ERS
