Potential genotoxic effects of GSM-1800 exposure on human cutaneous and nerve cells

Introduction The GSM-1800 signal has been in use for several years in Europe and questions raised about its potential biological effects, in view of the fact that, with respect to GSM-900, the increase in the carrier frequency corresponds to a more superficial absorption in the tissues. Consequently, the skin becomes an even more important target for the absorption of the radiofrequency radiation (R.F.R.) emitted by mobile phones. Nevertheless, brain tissues remain a critical target. Cells In order to determine whether R.F.R. at 1800 MHz could behave as a genotoxic agent, skin and brain cells were exposed to a 217-Hz-modulated GSM-1800 signal and assayed using the comet assay: (1) normal human epidermal keratinocytes (N.H.E.K.) and dermal fibroblasts (N.H.D.F.) which are cutaneous cells from epidermis and dermis respectively, and (2) the S.H. -S.Y.5.Y. and C.H.M.E.-5 human cell lines, which are neuroblastoma and micro-glial cells, respectively. Exposure The R.F.R. exposure system that was used in these experiments was manufactured by I.T. I.S. (Zurich, Switzerland). It consists in two shorted waveguides allowing to run exposed and sham conditions at the same time in the same culture incubator, at 37 Celsius degrees, 5% CO2. It is controlled by a software, which provides blind conditions until completion of data analysis. The specific absorption rate (S.A.R.) used was 2 W/kg, corresponding to the public exposure limit recommended by I.C.N.I.R.P. and the exposure duration was 48 hours. Comet assay At the end of the exposure, cells were removed from their Petri dish by trypsin/EDTA treatment, counted and 5 x 104 cells were used to detect DNA damage including single DNA breaks. Positive controls were performed using hydrogen peroxidase (1%, 1 hour). The genotoxic effects were detected using the alkaline comet assay kit (Trevigen slides) following the supplier procedure. Under these conditions, 6 independent experiments were performed for each cell type (2 Petri dishes by run). The analysis was done on at least 100 images from two comet slides (one per Petri dish) for each cellular model and exposure condition. Results The analysis of the slides is ongoing. Once the data analysis is completed, I.T.I.S. will break the blinding codes, and the results will be presented at the meeting. Acknowledgement: This work was supported by France Telecom R and D, Bouygues Telecom, the Cnrs and the Aquitaine Council for Research. (authors)