Effect of Exposure to the Edge Signal on Oxidative Stress in Brain Cell Models F. Poulletier de Gannes, a,b E. Haro, a A. Hurtier, a M. Taxile, a G. Ruffie ´, a B. Billaudel, a B. Veyret a,b and I. Lagroye a,b,1 a University of Bordeaux, IMS Laboratory and b EPHE Bioelectromagnetics laboratory, ENSCBP, 33607 Pessac, France Poulletier de Gannes, F., Haro, E., Hurtier, A., Taxile, M., Ruffie ´, G., Billaudel, B., Veyret, B. and Lagroye, I. Effect of Exposure to the Edge Signal on Oxidative Stress in Brain Cell Models. Radiat. Res. 175, 225–230 (2011). In this study we investigated the effect of the Enhanced Data rate for GSM Evolution (EDGE) signal on cells of three human brain cell lines, SH-SY5Y, U87 and CHME5, used as models of neurons, astrocytes and microglia, respectively, as well as on primary cortical neuron cultures. SXC-1800 waveguides (IT’IS- Foundation, Zu ¨rich, Switzerland) were modified for in vitro exposure to the EDGE signal radiofrequency (RF) radiation at 1800 MHz. Four exposure conditions were tested: 2 and 10 W/kg for 1 and 24 h. The production of reactive oxygen species (ROS) was measured by flow cytometry using the dichlorofluorescein diacetate (DCFH-DA) probe at the end of the 24-h exposure or 24 h after the 1-h exposure. Rotenone treatment was used as a positive control. All cells tested responded to rotenone treatment by increasing ROS production. These findings indicate that exposure to the EDGE signal does not induce oxidative stress under these test conditions, including 10 W/kg. Our results are in agreement with earlier findings that RF radiation alone does not increase ROS production. g 2011 by Radiation Research Society INTRODUCTION The widespread use of wireless communication devices has raised concerns about the effect of radiofrequency (RF) radiation on health. Many reports have focused on the possible biological effects of exposure to second- generation signals (GSM-900, -1800) and, more recently, to third-generation technology UMTS signals. To our knowledge, no data had previously been published on the effect of the EDGE (Enhanced Data rate for GSM Evolution) signal, which is widely used in Europe. The processes investigated in bioelectromagnetics include reactive oxygen species (ROS), because these molecules affect a large number of physiological functions. Oxidative stress results from metabolic reactions using oxygen and represents a disturbance in the equilibrium status of prooxidant/antioxidant reac- tions in living organisms. Low/moderate ROS concen- trations have beneficial physiological effects in responses to anoxia, defense against infectious agents, and a number of cell signaling systems. However, when ROS concentrations exceed the antioxidative capacity of the organism, cells enter into a state termed oxidative stress, where the excess ROS induce oxidative damage to cell components. Excess ROS may damage cell lipids, proteins or DNA, thereby inhibiting their normal function. Consequently, oxidative stress is implicated in a wide range of diseases, including cancer, diabetes, male infertility, autoimmune diseases, atherosclerosis and cardiovascular disorders, as well as in aging (1). The effects of RF fields on spontaneous or induced ROS production have mostly been studied in vitro, using immune system cells that generate ROS as part of their function, e.g. monocytes and lymphocytes (2–6). Human spermatozoa have also been exposed to a GSM-1800 signal. The authors observed an increase in ROS generation above 1 W/kg that was apparently related to the observed increase in oxidative DNA damage and fragmentation (7). Other studies have used various cells as models of the nervous system, including the SH- SY5Y neuroblastoma and SN56 cholinergic cell lines, as well as rat primary cortical neurons (8–10). The present experiments were the first to investigate the effect of the EDGE signal on three human brain cell lines, SH-SY5Y, U87 and CHME5, used as models of neurons, astrocytes and microglia, respectively, as well as on primary cortical neuron cultures. Four exposure condi- tions were tested: 2 and 10 W/kg for 1 and 24 h. ROS production was measured by flow cytometry using a dichlorofluorescein diacetate (DCFH-DA) probe at the end of the 24-h exposure or 24 h after the 1-h exposure. MATERIALS AND METHODS Cell Lines SH-SY5Y human neuroblastoma cells (ECACC No. 94030304, UK) were cultured in Ham’s-F12 medium (Invitrogen, Cergy Pontoise, France) supplemented with 1% nonessential amino acids, 1 Address for correspondence: University Bordeaux 1, IMS laboratory, Bioelectromagnetics group, ENSCBP, 16 avenue Pey- Berland, 33607 Pessac cedex, France; e-mail: isabelle.lagroye@ ims-bordeaux.fr. RADIATION RESEARCH 175, 225–230 (2011) 0033-7587/11 $15.00 g 2011 by Radiation Research Society. All rights of reproduction in any form reserved. DOI: 10.1667/RR2320.1 225