EXPOSURE TO 2.45 GHz MICROWAVE RADIATION PROVOKES CEREBRAL CHANGES IN INDUCTION OF HSP-90 α/β HEAT SHOCK PROTEIN IN RAT.

Abstract

Abstract-Physical agents such as non-ionizing continuous-wave 2.45 GHz radiation may cause damage that alters cellular homeostasis and may trigger activation of the genes that encode heat shock proteins (HSP). We used Enzyme-Linked ImmunoSorbent Assay (ELISA) and immunohistochemistry to analyze the changes in levels of HSP-90 and its distribution in the brain of Sprague-Dawley rats, ninety minutes and twenty-four hours after acute (30min) continuous exposure to 2.45 GHz radiation in a the Gigahertz Transverse Electromagnetic (GTEM cell). In addition, we studied further indicators of neuronal insult: dark neurons, chromatin condensation and nucleus fragmentation, which were observed under optical conventional or fluorescence microscopy after DAPI staining. The cellular distribution of protein HSP-90 in the brain increased with each corresponding SAR (0.034 ± 3.10 −3 , 0.069 ± 5.10 −3 , 0.27 ± 21.10 −3 W/kg), in hypothalamic nuclei, limbic cortex and somatosensorial cortex after exposure to the radiation. At twenty-four hours post-irradiation, levels of HSP-90 protein remained high in all hypothalamic nuclei for all SARs, and in the parietal cortex, except the limbic system, HSP-90 levels were lower than in non-irradiated rats, almost half the levels in rats exposed to the highest power radiation. Non-apoptotic cellular nuclei and a some dark neurons were found ninety minutes and twenty-four hours after maximal SAR exposure. The results suggest that acute exposure to electromagnetic fields triggered an imbalance in anatomical HSP-90 levels but the anti-apoptotic mechanism is probably sufficient to compensate the non-ionizing stimulus. Further studies are required to determine the regional effects of chronic electromagnetic pollution on heat shock proteins and their involvement in neurological processes and neuronal damage.

EMF radiation at 2450MHz triggers changes in the morphology and expression of heat shock proteins and glucocorticoid receptors in rat thymus

“…Nonionizing radiation also causes HSP changes in other tissues such as the thyroid [26], brain [18], skin [42] and myocardium [13]. Though tissue stress is often accompanied by an increase in HSPs, in this and prior studies [18,26] a transitory decrease in cellular stress protein levels was observed in different tissues within 24 h after radiation. This apparently contradictory finding has been reported by other authors as a cellular response to stimuli such as anoxia or ischemia [39,49].…”

“…The animal was then exposed to radiation for 30 min (single exposure). The experimental system used for applying radiation to the rats is described in Jorge-Mora et al [18].…”

Electromagnetic fields at 2.45 GHz trigger changes in heat shock proteins 90 and 70 without altering apoptotic activity in rat thyroid gland

“…This exposure setup provides good field uniformity and the behavior of a traveler wave can be simulated. The system components and operation were described in detail by Jorge-Mora et al (Jorge-Mora et al, 2010). …”

“…A Sprague-Dawley model R8 numerical (voxel) phantom rat (Schmid & Partner Engineering AG, 2009 reference manual) was used, weighing 198.3 g and composed of 60 different tissues assembled in 1.15 mm thick slices (tissue morphologies obtained by magnetic resonance images). The numerical phantom was radiated by a plane wave impinging its left side, with the magnetic field H parallel to its main axis (Jorge-Mora et al, 2010). The electrical field value E was determined by Eqn 1:where h is the septum height in the exposure zone (position of the MH), P TR ζ is the input power of the GTEM cell, P TR  = P IN −P REF , Z 0  = 50′ Ω is the input impedance of the cell, and ζ is the coefficient that depends on the ripple field in the position MH, which is considered to have a value of 2 (Schaffner Electrotest Gmbh GTEM Test Cells, Datasheet 2005).…”

“…Concern regarding potential risks of human exposure to EMFs has led to the creation of numerous experimental models for laboratory detection of biomarkers that are sensitive to this physical stimulus. Evidence has been found for changes in the expression of HSPs in various models of human cell lines (Lee et al, 2005; Caraglia et al, 2005; Alfieri et al, 2006) or in vivo rat tissue (Jorge-Mora et al, 2010) after exposure to experimental radio frequency systems. Other studies report no apparent changes in these biological markers after applying other experimental models in the laboratory (Wang et al, 2006; Chauhan et al, 2006; Valbonesi et al, 2008).…”