Impact of stress on electromagnetic field-induced corticosterone, cytokines and GFAP responses

Abstract

The widespread use of mobile phones raises the question of the effects of electromagnetic fields (EMF, 900 MHz) on the brain. Experimentally, local brain EMF exposures are performed in rats maintained in contention in Plexiglas rockets. Previous studies reported increased levels of cerebral glial fibrillary acidic protein (GFAP) after a single EMF exposure, suggesting a potential inflammatory process. However, these effects were not always reproduced, and the present study aims to test the contribution of protocol-induced stress in EMF-induced responses. To do so, plasmatic levels of corticosterone, GFAP, interleukin (IL)-1ß and IL-6 were measured 48 h following a single, 15 min, (0 or 6 W/kg) EMF-exposure in rats subjected to fear conditioning and tests (group 1 and 2). Test of stress was performed by measuring the same biological responses 30 min, 5 h and 24 h following (group 3) daily handling, (groups 4 and 5) a single, 15 min, (0 or 6 W/kg) GSM-exposure, and (group 6) a single 15 min sham (0W/kg GSM)-exposure followed by a fear conditioning session. Results showed that corticosterone increase was found only in groups 2 and 6, and no effect on IL-1ß, IL-6 or GFAP was obtained. According to these data, stressful situation linked to fear conditioning procedure did not modify GFAP or IL responses. Moreover, according to corticosterone measure, acute 15 min contention did not appear as a stressful event in our study. The use of fear conditioning in our protocol and the demonstration that it increases corticosterone after 30 min must be highlighted as a possible interacting parameter. Identification of contention-linked side effects may allow a better understanding of mobile phone EMF effects on neurobiological parameters