Human Keratinocytes in Culture Exhibit No Response When Exposed to Short Duration, Low Amplitude, High Frequency (900 MHz) Electromagnetic Fields in a Reverberation Chamber

We exposed normal human epidermal keratinocytes to short duration, high frequency, and low amplitude electromagnetic fields, similar to that used by mobile phone technologies. We paid particular attention to the control of the characteristics of the electromagnetic environment generated within a mode stirred reverberation chamber (statistical homogeneity and isotropy of the field and SAR distribution). Two non-thermal exposure conditions were tested on the epidermal cells: 10-min exposure with a field amplitude of 8 V/m, and 30 min with 41 V/m. Corresponding specific absorption rates ranged from 2.6 to 73 mW/kg (continuous wave, 900 MHz carrier frequency). We collected RNA from cells subjected to these conditions and used it for a large-scale microarray screening of over 47000 human genes. Under these conditions, exposure of keratinocytes to the electromagnetic field had little effect; only 20 genes displayed significant modulation. The expression ratios were very small (close to 1.5-fold change), and none of them were shared by the two tested conditions. Furthermore, those assayed using polymerase chain reaction did not display significant expression modulation (overall mean of the exposed samples: 1.20 +/- 0.18). In conclusion, the data presented here show that cultured keratinocytes are not significantly affected by EMF exposure. Bioelectromagnetics 32: 302-311, 2011. (c) 2010 Wiley-Liss, Inc.