Generation of reactive-oxygen species induced by electropermeabilization of Chinese hamster ovary cells and their consequence on cell viability.

Cells can be permeabilized transiently when pulsed by a brief intense external electric field. The molecular and cellular bases of cell electropermeabilization are still unclear. This process can be described by a local transient membrane organisation in which high permeability exists. In this study, using the chemiluminescent probe lucigenin, we showed that electropulsation of Chinese hamster ovary cells induced generation of reactive oxygen species at the electropermeabilized cell level. This generation was directly associated with the part of the membrane surface which is electrically restructured, as shown by its dependence on electric parameters. The electroinduced cell process was activated by Ca2+ and Mg2+ ions, and by exogenous adenosine 5'-triphosphate. A metal-ion-catalyzed Haber-Weiss reaction was thought to occur in the process, as shown by the action of effector molecules of Haber-Weiss reaction such as the chelating agent EDTA, and the hydroxyl radical scavenger dimethylsulfoxide. The modulation of the oxygen species electroinduction and the use of antioxidant products (dimethylsulfoxide, sodium L-ascorbate) showed that cell survival after electric treatment was directly correlated to the oxidative jump intensity. This observation had to be associated with the cell-damaging action of oxygen-reactive species.