Effects of the exposure of 2.14GHz W-CDMA radiofrequency electromagnetic fields to rats on body temperature increase and heat shock proteins expression

The radio frequency-electromagnetic field (RF-EMF) exposure and heat shock protein (Hsp) expression has been discussed, but there is no data on the relationship between thermal increase by RF-EMF and Hsp expression. Rats were exposed to RF-EMFs [2.14 GHz, wideband-code division multiple access (W-CDMA) signals] for 2 h/day for 3 days or 1 h/day for 10 days with a whole body average-specific absorption rate (WBA-SAR) of 4 W/kg or 0.4 W/kg, respectively. It appeared the intraperitoneal temperature was increased during RF-EMFs exposure and the Hsp27 and Hsp110 genes were significantly upregulated in the cerebral cortex and cerebellum at 4 W/kg, but protein upregulation was not detected. In contrast, there was no significant change in any of the genes at 0.4 W/kg. These results indicated that the thermal increase of the body by RF-EMF exposure plays critical role on Hsp expression.