Pulsed electromagnetic field at 9.71 GHz increase free radical production in yeast (Saccharomyces cerevisiae)

Potential human health hazards have been reported after exposure to electromagnetic fields at low power density. Increased oxidative stress has been suggested as a potential mechanism involved in long-term effect of such exposure. In the present work, yeast cultures were exposed for 20 min to a 9.71 GHz pulsed electromagnetic field at specific absorption rates (SAR) from 0.5 W/kg to 16 W/kg. Oxidative perturbations were investigated using ESR spin trapping experiments and their impacts on membrane fluidity were assessed using spin label five nitroxide stearate. The experiments using the water-soluble spin trap alpha-(4-pyridyl-1-oxide)-N-t-butylnitrone and the lipid-soluble N-tert-Butyl-alpha-phenylnitrone showed an increase of spin adduct production both in low power density exposure (SAR < 4 W/kg) and in thermal conditions (SAR > 4 W/kg). The membrane fluidity diminutions after exposure in all the conditions were consistent with lipid peroxidation. The overall results suggest an increase of the free radical production in the intra cellular compartment; however no effect on the yeast vitality was found. (C) 2008 Elsevier Masson SAS. All rights reserved.