EMF radiation at 2450 MHz triggers changes in the morphology and expression of heat shock proteins and glucocorticoid receptors in rat thymus.
OBJECTIVE
Electromagnetic fields (EMFs) can act as inducers or mediators of stress response through the production of heat shock proteins (HSPs) that modulate immune response and thymus functions. In this study, we analyzed cellular stress levels in rat thymus after exposure of the rats to a 2.45 GHz radio frequency (RF) using an experimental diathermic model in a Gigahertz Transverse Electromagnetic (GTEM) chamber.


METHODS
In this experiment, we used H&E staining, the ELISA test and immunohistochemistry to examine Hsp70 and Hsp90 expression in the thymus and glucocorticoid receptors (GR) of 64 female Sprague–Dawley rats exposed individually to 2.45 GHz (at 0, 1.5, 3.0 or 12.0 W power). The 1 g averaged peak and mean SAR values in the thymus and whole body of each rat to ensure that sub-thermal levels of radiation were being reached.


RESULTS
The thymus tissue presented several morphological changes, including increased distribution of blood vessels along with the appearance of red blood cells and hemorrhagic reticuloepithelial cells. Levels of Hsp90 decreased in the thymus when animals were exposed to the highest power level (12 W), but only one group did not show recovery after 24 h. Hsp70 presented no significant modifications in any of the groups. The glucocorticoid receptors presented greater immunomarking on the thymic cortex in exposed animals.


CONCLUSIONS
Our results indicate that non-ionizing sub-thermal radiation causes changes in the endothelial permeability and vascularization of the thymus, and is a tissue-modulating agent for Hsp90 and GR.
Morphological Sciences Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
M J
MJ
Misa-Agustiño
Institute of Food Research and Analysis, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
J M
JM
Leiro-Vidal
Pharmacy and Pharmaceutical Technology Department, Institute of Industrial Pharmacy, Faculty of Pharmacy, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
J L
JL
Gomez-Amoza
Morphological Sciences Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
M T
MT
Jorge-Mora
Morphological Sciences Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
F J
FJ
Jorge-Barreiro
Applied Physics Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
A A
AA
Salas-Sánchez
Applied Physics Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
F J
FJ
Ares-Pena
Morphological Sciences Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain. Electronic address: melena.lopez.martin@usc.es.
E
E
López-Martín
D000818:Animals; D001831:Body Temperature / Q000528:radiation effects; D004574:Electromagnetic Fields; D004730:Endothelium, Vascular / Q000528:radiation effects; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000528:radiation effects; D018841:HSP90 Heat-Shock Proteins / Q000096:biosynthesis / Q000528:radiation effects; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000528:radiation effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011965:Receptors, Glucocorticoid / Q000096:biosynthesis* / Q000528:radiation effects*; D012039:Regional Blood Flow / Q000528:radiation effects; D013312:Stress, Physiological / Q000528:radiation effects; D013950:Thymus Gland / Q000098:blood supply / Q000378:metabolism* / Q000528:radiation effects*
D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D011965:Receptors, Glucocorticoid
GTEM; HSP; Non-ionizing radiation; SAR; Sub-thermal; Thymus