Exposure time-dependent thermal effects of radiofrequency electromagnetic field exposure on the whole body of rats.
We investigated the thermal effects of radiofrequency electromagnetic fields (RF-EMFs) on the variation in core temperature and gene expression of some stress markers in rats. Sprague-Dawley rats were exposed to 2.14 GHz wideband code division multiple access (W-CDMA) RF signals at a whole-body averaged specific absorption rate (WBA-SAR) of 4 W/kg, which causes behavioral disruption in laboratory animals, and 0.4 W/kg, which is the limit for the occupational exposure set by the International Commission on Non-Ionizing Radiation Protection guideline. It is important to understand the possible in vivo effects derived from RF-EMF exposures at these intensities. Because of inadequate data on real-time core temperature analyses using free-moving animal and the association between stress and thermal effects of RF-EMF exposure, we analyzed the core body temperature under nonanesthetic condition during RF-EMF exposure. The results revealed that the core temperature increased by approximately 1.5°C compared with the baseline and reached a plateau till the end of RF-EMF exposure. Furthermore, we analyzed the gene expression of heat-shock proteins (Hsp) and heat-shock transcription factors (Hsf) family after RF-EMF exposure. At WBA-SAR of 4 W/kg, some Hsp and Hsf gene expression levels were significantly upregulated in the cerebral cortex and cerebellum following exposure for 6 hr/day but were not upregulated after exposure for 3 hr/day. On the other hand, there was no significant change in the core temperature and gene expression at WBA-SAR of 0.4 W/kg. Thus, 2.14-GHz RF-EMF exposure at WBA-SAR of 4 W/kg induced increases in the core temperature and upregulation of some stress markers, particularly in the cerebellum.
Department of Hygienic Chemistry, Meiji Pharmaceutical University.
Shin
S
Ohtani
Akira
A
Ushiyama
Machiko
M
Maeda
Kenji
K
Hattori
Naoki
N
Kunugita
Jianqing
J
Wang
Kazuyuki
K
Ishii
D000818:Animals; D001522:Behavior, Animal / Q000528:radiation effects; D001833:Body Temperature Regulation / Q000528:radiation effects*; D001921:Brain / Q000378:metabolism / Q000528:radiation effects*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004574:Electromagnetic Fields; D005786:Gene Expression Regulation / Q000528:radiation effects; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D009043:Motor Activity / Q000528:radiation effects; D011846:Radio Waves; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014916:Whole-Body Irradiation
D016207:Cytokines; D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D014157:Transcription Factors