ID Number		1630
Study Type		In Vitro
Model		900 MHz (GSM, CW) exposure to neuroblastoma cells and analysis of cell cycle and apoptosis
Details		SH-SY5Y human neuroblastoma cells were exposed to 900 MHz (GSM, CW) for 24 hours at 0.25 W/kg (GSM) or 2 W/kg (CW). The authors report 2 degree C temperature elevations during 2 W/kg CW exposure. The authors report no statistically significant effects of either GSM or CW exposure on apoptosis either immediately following or 24 hours after the exposure period (using DAPI staining, flow cytometry / TUNEL assay, and caspase-3 activity). Non-RF heating at 39 degrees also showed no increase in apoptotic activity. In a related study, the authors used primary cultured neurons from embryonic Wistar rats and exposed to 900 MHz as above. Again, TUNEL assay showed no effect on apoptosis. In a subsequent study, however, effects of CW (but not GSM) exposure were observed using similar cultured rat neurons exposed to 900 MHz for 24 hours at a reported average SAR (at the level of the cell layer) of 2 W/kg. Cells assayed either immediately after or 24 hours after exposure demonstrated an increase in apoptosis by TUNEL assay, Caspase 3, and AIF assay. The authors also report a temperature increase of ~1 degree C during exposure, but no effect in heat (39 degree C) controls. The authors suggest apoptitic induction by CW RF through a caspase-independent pathway. Although elevated temperature (39 degrees) also increased apoptosis in some studies, the authors indicate the CW RF exposed rate was higher and a lack of heat shock proteins in the AIF assay suggested heating was not the underlying mechanism.
Findings		Effects
Status		Completed With Publication
Principal Investigator		Limoges Univ Hosp, France - catherine.yardin@unilim.fr
Funding Agency		FSR, France
Country		FRANCE
References		Joubert, V et al. Radiation Research, (2008) 169:38-45 Joubert, V et al. Bioelectromagnetics, (2007) 28:115-121 Joubert, V et al. Int J Radiat Biol, (2006) 82:267-275
Comments		Although a temperature increase of ~ 1 degree C was suggested at the cell layer during exposure, it is highly likely there were non-uniform hot spots that may have been hotter. Since apoptosis was observed in the 39 degree heat controls, it is not surprising that further elevated temperatures might cause increased apoptotic activity.