Effects of GSM and UMTS mobile telephony signals on neuron degeneration and blood-brain barrier permeation in the rat brain.

Blood-brain barrier (BBB) permeation and neuron degeneration were assessed in the rat brain following exposure to mobile communication radiofrequency (RF) signals (GSM-1800 and UMTS-1950). Two protocols were used: (i) single 2 h exposure, with rats sacrificed immediately, and 1 h, 1, 7, or 50 days later, and (ii) repeated exposures (2 h/day, 5 days/week, for 4 weeks) with the effects assessed immediately and 50 days after the end of exposure. The rats' heads were exposed at brain-averaged specific absorption rates (BASAR) of 0.026, 0.26, 2.6, and 13 W/kg. No adverse impact in terms of BBB leakage or neuron degeneration was observed after single exposures or immediately after the end of repeated exposure, with the exception of a transient BBB leakage (UMTS, 0.26 W/kg). Fifty days after repeated exposure, the occurrence of degenerating neurons was unchanged on average. However, a significant increased albumin leakage was detected with both RF signals at 13 W/kg. In this work, the strongest, delayed effect was induced by GSM-1800 at 13 W/kg. Considering that 13 W/kg BASAR in the rat head is equivalent to 4 times as much in the human head, deleterious effects may occur following repeated human brain exposure above 50 W/kg.

In situ expression of heat-shock proteins and 3-nitrotyrosine in brains of young rats exposed to a WiFi signal in utero and in early life.

The bioeffects of exposure to Wireless High-Fidelity (WiFi) signals on the developing nervous systems of young rodents was investigated by assessing the in vivo and in situ expression levels of three stress markers: 3-Nitrotyrosine (3-NT), an oxidative stress marker and two heat-shock proteins (Hsp25 and Hsp70). These biomarkers were measured in the brains of young rats exposed to a 2450 MHz WiFi signal by immunohistochemistry. Pregnant rats were first exposed or sham exposed to WiFi from day 6 to day 21 of gestation. In addition three newborns per litter were further exposed up to 5 weeks old. Daily 2-h exposures were performed blind in a reverberation chamber and whole-body specific absorption rate levels were 0, 0.08, 0.4 and 4 W/kg. 3-NT and stress protein expression was assayed in different areas of the hippocampus and cortex. No significant difference was observed among exposed and sham-exposed groups. These results suggest that repeated exposure to WiFi during gestation and early life has no deleterious effects on the brains of young rats.

Rat fertility and embryo fetal development: influence of exposure to the Wi-Fi signal.

In recent decades, concern has been growing about decreasing fecundity and fertility in the human population. Exposure to non-ionizing electromagnetic fields (EMF), especially radiofrequency (RF) fields used in wireless communications has been suggested as a potential risk factor. For the first time, we evaluated the effects of exposure to the 2450MHz Wi-Fi signal (1h/day, 6days/week) on the reproductive system of male and female Wistar rats, pre-exposed to Wi-Fi during sexual maturation. Exposure lasted 3 weeks (males) or 2 weeks (females), then animals were mated and couples exposed for 3 more weeks. On the day before delivery, the fetuses were observed for lethality, abnormalities, and clinical signs. In our experiment, no deleterious effects of Wi-Fi exposure on rat male and female reproductive organs and fertility were observed for 1h per days. No macroscopic abnormalities in fetuses were noted, even at the critical level of 4W/kg.

Effect of in utero wi-fi exposure on the pre- and postnatal development of rats.

BACKGROUND: The increase in exposure to the Wireless Fidelity (Wi-Fi) wireless communication signal has raised public health concerns especially for young people. Animal studies looking at the effects of early life and prenatal exposure to this source of electromagnetic fields, in the radiofrequency (RF) range, on development and behavior have been considered as high priority research needs by the World Health Organization. METHODS: For the first time, our study assessed the effects of in utero exposure to a 2450 MHz Wi-Fi signal (2 hr/day, 6 days/week for 18 days) on pregnant rats and their pups. Three levels in terms of whole-body specific absorption rate were used: 0.08, 0.4, and 4 W/kg. The prenatal study on fetuses delivered by caesarean (P20) concerned five females/group. The dams and their offspring were observed for 28 days after delivery (15 females/group). RESULTS: For all test conditions, no abnormalities were noted in the pregnant rats and no significant signs of toxicity were observed in the pre- and postnatal development of the pups, even at the highest level of 4 W/kg. CONCLUSIONS: In the present study, no teratogenic effect of repeated exposures to the Wi-Fi wireless communication signal was demonstrated even at the highest level of 4 W/kg. The results from this screening study aimed at investigating Wi-Fi effects, strengthen the previous conclusions that teratology and development studies have not detected any noxious effects of exposures to mobile telephony-related RF fields at exposure levels below standard limits.

In utero and early-life exposure of rats to a Wi-Fi signal: screening of immune markers in sera and gestational outcome.

An experimental approach was used to assess immunological biomarkers in the sera of young rats exposed in utero and postnatal to non-ionizing radiofrequency fields. Pregnant rats were exposed free-running, 2 h/day and 5 days/week to a 2.45 GHz Wi-Fi signal in a reverberation chamber at whole-body specific absorption rates (SAR) of 0, 0.08, 0.4, and 4 W/kg (with 10, 10, 12, and 9 rats, respectively), while cage control rats were kept in the animal facility (11 rats). Dams were exposed from days 6 to 21 of gestation and then three newborns per litter were further exposed from birth to day 35 postnatal. On day 35 after birth, all pups were sacrificed and sera collected. The screening of sera for antibodies directed against 15 different antigens related to damage and/or pathological markers was conducted using enzyme-linked immunosorbent assay (ELISA). No change in humoral response of young pups was observed, regardless of the types of biomarker and SAR levels. This study also provided some data on gestational outcome following in utero exposure to Wi-Fi signals. Mass evaluation of dams and pups and the number of pups per litter was monitored, and the genital tracts of young rats were observed for abnormalities by measuring anogenital distance. Under these experimental conditions, our observations suggest a lack of adverse effects of Wi-Fi exposure on delivery and general condition of the animals.

Lack of effect of 50-Hz magnetic field exposure on the binding affinity of serotonin for the 5-HT 1B receptor subtype.

There is some concern that exposure to extremely low-frequency magnetic fields (MF) causes adverse health effects via signal transduction pathways. Two previous studies reported that exposure to 50-Hz MF decreased the binding affinity of the 1B receptor subtype of serotonin (5-HT) in rat brain membranes. The aim of this study was to investigate whether the exposure to MF affects binding to the 5-HT(1B) receptor and a physiological function associated with 5-HT(1B) receptor activation. Rat brain crude membrane fractions, including 5-HT(1B) receptor and C6-glial cells transfected with human 5-HT(1B) receptor gene, were exposed to 50-Hz MF at 1 mT using Merritt coils under temperature-regulated conditions. In the rat crude membrane, there was no significant difference in the affinity constant of [(3)H]-5-HT between exposed (K(d): 0.92±0.38 nM) and sham-exposed (K(d): 1.00±0.32 nM). The lack of affinity change after exposure was also confirmed using a chemical agonist of the 5-HT receptor, [(3)H]-5-carboxytryptamine (K(d): 0.59±0.06 nM for exposed and 0.71±0.08 nM for sham). Similar negative results in terms of affinity constant were obtained on the human 5-HT(1B) receptor in C6-glial cells. In addition, forskolin-stimulated cAMP production was inhibited by 5-HT administration in a dose-dependent manner in C6-glial cells, but exposure did not modify the inhibitory response. This study thus failed to confirm the previous results and findings suggest that exposure to MF below the current occupational limit does not affect the physiological function involved in 5-HT(1B) receptor subtypes.

Amyotrophic lateral sclerosis (ALS) and extremely-low frequency (ELF) magnetic fields: a study in the SOD-1 transgenic mouse model.

There is some evidence from epidemiological studies of an association between occupational exposure to electromagnetic fields and Amyotrophic Lateral Sclerosis (ALS). Our aim was to perform, for the first time, an animal study in a controlled magnetic environment. We used the SOD-1 mouse model to assess the possible effect of ELF magnetic fields on development of the disease. Seven mice per group were exposed to 50 Hz magnetic fields at two intensities (100 and 1000 microT(rms)) before the onset of the clinical signs of ALS. Exposure lasted 7 weeks, and body weight, motor performance and life span were monitored. Our results did not reveal any evidence of a link between ELF exposure and ALS in this transgenic animal model.

Effects of head-only exposure of rats to GSM-900 on blood-brain barrier permeability and neuronal degeneration.

Salford et al. reported in 2003 that a single 2-h exposure to GSM-900 mobile telephony signals induced brain damage (increased permeability of the blood-brain barrier and presence of dark neurons) 50 days after exposure. In our study, 16 Fischer 344 rats (14 weeks old) were exposed head-only to the GSM-900 signal for 2 h at various brain-averaged SARs (0, 0.14 and 2.0 W/kg) or were used as cage or positive controls. Albumin leakage and neuron degeneration were evaluated 14 and 50 days after exposure. No apoptotic neurons were found 14 days after the last exposure using the TUNEL method. No statistically significant albumin leakage was observed. Neuronal degeneration, assessed using cresyl violet or the more specific marker Fluoro-Jade B, was not significantly different among the tested groups. No apoptotic neurons were detected. The findings of our study did not confirm the previous results of Salford et al.

Effects of exposure to DAMPS and GSM signals on ornithine decarboxylase (ODC) activity: I. L-929 mouse fibroblasts.

PURPOSE: A temporary increase in ornithine decarboxylase (ODC) activity was reported in lysed L-929 fibroblasts after exposure to the microwaves emitted by Digital Advanced Mobile Phone System (DAMPS-835 MHz, 2.5 W/kg, 8 hours). Confirmation of these data was undertaken, given the suggested potential physiopathological consequences, i.e., tumour promotion. MATERIALS AND METHODS: Murine L-929 fibroblasts were exposed at various Specific Absorption rates (SAR) to (DAMPS) or Global System for Mobile communications (GSM) signals using different set-ups. Cell ODC activities were assayed using 14CO2 generation from 14C-labeled L-ornithine. RESULTS: ODC activity in live L-929 cells showed no significant alteration after exposure at an SAR of 2.5 W/kg, for one hour at the end of exposure to 50 Hz-modulated DAMPS-835 using Transverse Electro-Magnetic (TEM) cells. No significant alteration in ODC activity was observed at 6 W/kg, with active fans to regulate temperature (37 degrees C). Tests using cell lysed after exposure in another temperature-controlled set-up (waveguides) did not confirm the published studies reporting increased ODC activity in Radio-Frequency radiation (RFR)-exposed L-929 cells. In the second part of the study, no alteration of ODC activity was detected when L-929 cells were exposed to different RFR signals: 217 Hz modulated GSM-900 (wire-patch antenna) or GSM-1800 (waveguides), and lysed before ODC measurement. CONCLUSION: We conclude that under our exposure conditions, DAMPS-835 and GSM signals have no influence on ODC activity in L-929 cells.

Effects of exposure to DAMPS and GSM signals on ornithine decarboxylase (ODC) activity: II. SH-SY5Y human neuroblastoma cells.

PURPOSE: An increase in Ornithine Decarboxylase (ODC) activity was reported in L929 murine fibroblast cells after exposure to a digital cellular telephone signal. This result was not confirmed by several other studies, including the one reported in a companion paper. As a partner in the Perform-B programme, we extended this study to human neuroblastoma cells (SH-SY5Y), using well-defined waveguide systems to imitate exposure to radiofrequency radiation (RFR): Digital Advanced Mobile Phone System (DAMPS) or Global System for Mobile communications (GSM) signals emitted by mobile phones. MATERIALS AND METHODS: Human neuroblastoma cells (SH-SY5Y) were exposed at various Specific Absorption Rates (SAR) to DAMPS or GSM signals using different set-ups. Cell ODC activities were assayed using 14CO2 generation from 14C-labeled L-ornithine. RESULTS: SH-SY5Y cells were incubated for 20 hours, and were blindly exposed to 50 Hz-modulated DAMPS-835 or 217 Hz-modulated GSM-1800 for 8 or 24 h using Information Technologies in Society (IT'IS) waveguides equipped with fans. After cell lysis, ODC activity was determined using 14C-labeled L-ornithine. ODC activity was estimated by the 14CO2 generated from 14C-labeled L-ornithine, as generated d.p.m. 14CO2/h/mg protein. The results showed that, irrespective of the signal used (835 MHz/DAMPS, or 1800 MHz/GSM) and exposure conditions (duration and SAR), human SH-SY5Y neuroblastoma cells did not exhibit any alteration in ODC enzyme activity. CONCLUSION: This work did not show a significant effect of mobile phone RFR exposure on ODC activity in neuroblastoma cells (SH-SY5Y).

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

PURPOSE: 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 Heat-shock 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 < 5 W/kg), there was no evidence that GSM signals alter HSP expression in rat skin.

Human skin cell stress response to GSM-900 mobile phone signals. In vitro study on isolated primary cells and reconstructed epidermis.

In recent years, possible health hazards due to radiofrequency radiation (RFR) emitted by mobile phones have been investigated. Because several publications have suggested that RFR is stressful, we explored the potential biological effects of Global System for Mobile phone communication at 900 MHz (GSM-900) exposure on cultures of isolated human skin cells and human reconstructed epidermis (hRE) using human keratinocytes. As cell stress markers, we studied Hsc70, Hsp27 and Hsp70 heat shock protein (HSP) expression and epidermis thickness, as well as cell proliferation and apoptosis. Cells were exposed to GSM-900 under optimal culture conditions, for 48 h, using a specific absorption rate (SAR) of 2 W x kg(-1). This SAR level represents the recommended limit for local exposure to a mobile phone. The various biological parameters were analysed immediately after exposure. Apoptosis was not induced in isolated cells and there was no alteration in hRE thickness or proliferation. No change in HSP expression was observed in isolated keratinocytes. By contrast, a slight but significant increase in Hsp70 expression was observed in hREs after 3 and 5 weeks of culture. Moreover, fibroblasts showed a significant decrease in Hsc70, depending on the culture conditions. These results suggest that adaptive cell behaviour in response to RFR exposure, depending on the cell type and culture conditions, is unlikely to have deleterious effects at the skin level.