In-vitro Exposure of Neuronal Networks to a GSM-1800 Signal

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Neuroinflammation and mobile phone exposure: the NIMPHE project

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Effect of GSM-900 and -1800 signals on the skin of hairless rats. III: Expression of heat shock proteins

International audiencePurpose: We previously reported the inability of Global System for Mobile communication (GSM) signals at 900 (GSM- 900) and 1800 (GSM-1800) MegaHertz (MHz) to induce morphological and physiological changes in epidermis of Hairless rats. The present work aimed at investigating heat shock proteins (HSP) expression - as a cellular stress marker - in the skin of Hairless rats exposed to GSM-900 and -1800 signals. Materials and methods: We studied the expression of the Heat-shock cognate (Hsc) 70, and the inducible forms of the Heatshock proteins (Hsp) 25 and 70. Rat skin was locally exposed using loop antenna and restrain rockets to test several Specific Absorption Rates (SAR) and exposure durations: (i) single exposure: 2 hours at 0 and 5 W/kg; (ii) repeated exposure: 2 hours per day, 5 days per week, for 12 weeks, at 0, 2.5, and 5 W/kg. HSP expression was detected on skin slices using immunolabeling in the epidermal area. Results: Our data indicated that neither single nor repeated exposures altered HSP expression in rat skin, irrespective of the GSM signal or SAR considered. Conclusions: Under our experimental conditions (local SAR 55 W/kg), there was no evidence that GSM signals alter HSP expression in rat ski

Exposure to Radiofrequency Fields and Heat Shock Protein (Hsp) Expression in the Rat Brain

The expression of heat-shock proteins (HSP) had been observed after exposure to low-level radiofrequency fields (RFR) exposure in worms and in human endothelial cells . These data have been hypothetically linked at best to stress, and at worse to cancer. Further studies failed to confirm these RFR bioeffects, while very few experiments have looked at the expression of Hsp in mammals exposed to RFR. Earlier however, changes in hsp70 mRNA were reported in the brain on rats exposed to a GSM-900 signal. In this study, we have investigated the effects of a single exposure or repeated exposures to two mobile phone-related RFR signals (GSM-1800 MHz and UMTS) on Hsp25 and Hsp70 expression in rat brains. Groups of 8 male Wistar rats were exposed to RFR using a loop antenna at a brain averaged specific absorption rate (BASAR) of 2.6 W/kg. BASAR characterisation was performed as previously described at 900 MHz . Rats were submitted to either a single 2-hour exposure or repeated exposures (two hours/day, five days/week, four weeks). Controls for restraining stress, cage-control and positive-control rats were included. Rats were trained to the setup to avoid stress. At the end of exposure, rat brains were fixed, frozen, and coded. 10 μm sections were prepared and stained with anti-Hsp25 and anti-inducible Hsp70 antibodies. The cerebral cortex and the hippocampus were analysed. The significance of differences between groups was evaluated using the Kruskal-Wallis test. Repeated exposures to UMTS induced an increased expression of Hsp25 and Hsp70 in the retrosplenial cortex and in the hippocampus. A drop in the amount of both Hsp was observed in both the cortex and the hippocampus after a single exposure to GSM-1800, while repeated exposures to GSM-1800 increased Hsp25 expression in the motor and retrosplenial cortex and Hsp70 in the motor cortex. Decreased expression of Hsp, as observed after single exposure to GSM-1800, has been described after treatments with Benzo[a]pyrene or TNFα, but its physiological significance is not clearly established. Our results suggested that repeated exposures to UMTS and GSM-1800 are capable of increasing HSP expression. According to the experimental evidence of the carcinogenic potential of low-level RFR, increase in HSP expression is unlikely to be linked to cancer. We hypothesised that repeated exposures to mobile phone signals may be perceived as a stress and may participate in an adaptative process in the rat brain

Using real-time impedance-based assays to monitor the effects of environmental radiofrequency signals on breast cancer and neuroblastoma cell lines

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Radiofrequency field emitted by mobile phones and alteration of the blood-brain barrier: how strong is the experimental evidence?

International audienceIt is known that high power, thermal radiofrequency radiation (RFR) can alter the blood-brain barrier (BBB) permeability with a brain av eraged specific absorption rate (BASAR) threshold evaluated at around 100 W/kg (1). Mobile communication technologies are using RFR with exposure guidelines for public local exposure at 2 W/kg, far lower than the threshold previously mentioned. However, in a paper recently published (2) the occurrence of BBB leakage and brain damage (presence of dark neurons) has been reported 50 days after a single 2-hour exposure of rats to a GSM-900 signal. In that investigation however, biais could have occurred as, for instance, exposed animals were mixed in terms of age (12- to 26-week old) and gender, while those differences were not taken into account in the analysis. Moreover, other groups have published contradictory results (3). Our group undertook a confirmation study of the Salford experiments within an international collaborative programme including technical improvements. Our study includes the detection of dark neurons, alteration of the permeability of the BBB and apoptosis 14 or 50 days after GSM-900 exposure. The exposure setup was the loop antenna that allows for head-only exposure. Five groups of 16 Fisher 344 rats (14 -week old) were exposed to GSM-900 during 2 hours at various SAR levels (0, 0.14 and 2.0 W/kg), or were used as cage control or positive controls. Positive controls were treated with kainic acid (10 mg/kg) or by cold injury (dry ice during 5 minutes). After exposure, rats were kept alive during 14 or 50 days to study brain damages. Then, they were anesthetized with urethane (i.p. 1.5 mg/kg), perfused with PBS and fixed with paraformaldehyde 4% (PAF 4%). Brains were extracted and put in cold PAF 4% during the following night, then placed in cold sucrose 20% during 2-3 days, frozen with isopentane and placed at -80°C. Coding was done on brains. Frozen brains were cut in 3 different areas (frontal, median and posterior). Slides were stained with cresyl violet and FluoroJade B to detect the presence of dark neurons. Apoptosis was investigated using the TUNEL method and endogenous albumin visualized using immuno-histochemical labeling as a marker of leakage of the blood -brain barrier. Preliminary data on 2 to 4 rats per group do not suggest that GSM-900 exposure could induce alterations in the brain of rats. The experiments will be completed and a review on this topics, including our contribution, will be presente

Effects of a 4-week chronic head-only exposure to GSM-1800 or UMTS signals on the brain of rats

(Poster

Do GSM-900 signals affect blood-brain barrier permeability and neuron viability?

OralInternational audienceObjective. Our group has undertaken a confirmation study of the work performed by the Swedish group of Leif Salford, which reported the occurrence of blood-brain barrier (BBB) permeation and brain damage (presence of dark neurons), 50 days after a single 2-hour exposure of rats to a GSM-900 signal. Preliminary results were presented at the BioEM05 meeting (Haro et al, P-A-133). We improved the Swedish analysis procedure by adding the detection of apoptosis and a more specific staining method for dark neurons. The detection of dark neurons and BBB permeability was assessed 14 and 50 days after GSM-900 exposure. Apoptosis was detected 14 days after exposure. Methods. The exposure setup was the loop antenna that allows for head-only exposure. Five groups of 16 Fisher 344 rats (14-week old) were exposed to the GSM-900 signal during 2 hours at various brain averaged SAR levels (0, 0.14 and 2.0 W/kg), or were used as cage control or positive controls. Positive controls were treated with kainic acid (10 mg/kg) or by cold injury (dry ice during 5 minutes). After exposure, rats were kept alive during 14 or 50 days to study brain damages. Then, they were anesthetized with urethane (i.p. 1.5 mg/kg), perfused with PBS and fixed with paraformaldehyde 4 % (PAF 4 %). Brains were extracted and put in cold PAF 4 % during the following night, then placed in cold 20 % sucrose during 2-3 days, frozen in isopentane and placed at -80 C. Coding was done on brains. Frozen brains were cut in 3 different areas (frontal, median and posterior). Slices were stained with cresyl violet and FluoroJade B to detect the presence of dark neurons. Apoptosis was investigated using the TUNEL method and endogenous albumin visualized using immuno-histochemical labeling as a marker of leakage of the blood-brain barrier. The numbers of dark neurons labeled with cresyl violet, apoptosis and albumin leakage were evaluated by counting. Fluorojade B staining was measured by image analysis using the Aphelion software. Analyses in brain sections were performed in particular in the motor cortex and the hippocampus (CA1, CA2, CA3 and DG). Kruskal-Wallis statistical tests were used. Results. Using the two methods to detect dark neurons, we found no significant difference between sham and exposed animals at both 14 and 50 days after exposure. These results are in agreement with the absence of neurons dying via apoptosis 14 days after exposure. For all tested SARs, GSM-900 did not induce significant albumin leakage in any brain area. Discussion and Conclusion. Our study did not confirm that GSM-900 exposure induce brain damages as previously described. Our data, together with those of the collaborative groups (Brooks Air Force Base, USA and the National Institute of Public Health, Japan) , should help to reach a conclusion about the effect of GSM-900 signals on the brai

Effects on brain dark neurons of Wistar-Han rats exposed head-only to GSM-1800 or UMTS signals

(Oral

Childhood Leukaemia and Magnetic Fields: the CLeMAn project as an in vivo approach.

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