Authors

Ziemann C, Brockmeyer H, Reddy SB, Prihoda TJ, Kuster N, Tillmann T, Dasenbrock C. Absence of genotoxic potential of 902 MHz (GSM) and 1747 MHz (DCS) wireless communication signals: In vivo two-year bioassay in B6C3F1 mice. Int J Radiat Biol. 2009 Apr Ahead of print. 8:1-11.

Background
Although non-ionizing radiofrequency (RF) radiation is of increased concern for its potential adverse effects on human health, few investigators have studied potential genotoxic effects of chronic exposure.  By using the rodent micronucleus (MN) assay of broken chromosomal fragments and whole chromosomes that are not incorporated into daughter cells at the time of cell division, the MN test can identify both clastogenic and
aneugenic agents.

Methods
The study was performed as an add-on to the European PERFORM-A1 mouse carcinogenicity study.  All scientists conducted the study ‘blind.’  Mice were young adult, specified pathogen-free B6C3F1/Crl BR male and female mice, 4–5 weeks of age.  They were kept in two separate rooms, one for 902 MHz (GSM) and another for 1747 MHz (DCS) experiments, under laboratory standard conditions.  A total of 1,170 mice (585 males and 585 females) were randomized by weight into groups.  Each exposure group initially consisted of 50+15 males and 50+15 females, where fifty animals of each sex were used for the two-year exposure study, while the other 15 animals per group were used for interim examinations (organ weights, hematology, gross pathology, and histopathology) after a 12-month exposure period. Mice were restrained in tubes and were sham-exposed or exposed to RF for 2 hours/day on 5 days/week over a period of two years. The RF signals simulated exposure from GSM (902 MHz) and DCS (1747 MHz) handsets. Each exposure session (duration 2 hours) was divided into three phases of 40 minunites each:  ‘GSM Basic’ was applied simulating the exposure conditions during continuous talking (target whole-body-averaged specific absorption rate (SAR) for the high group was 4 W/kg), ‘GSM Talk’ simulated a conversation with temporal switching between non-discontinuous transmission modes (2.7 W/kg), and ‘GSM Environment’ simulated exposure during a conversation (1.1 W/kg).  All mice alive at the end of the two-year RF-exposure period were included in this study, and necropsies were completed between day 3 and day 19 after the last RF- or sham-exposure.

Results
Concerning polychromatic erythrocytes (PCE) in peripheral blood, there was no toxic effect of RF exposure on blood formation.  In assessing micronuclei in polychromatic erythrocytes of the peripheral blood, which is a measure of treatment-induced clastogenic activity and mitotic damage, there was no evidence of an RF-induced effect on frequency of micronucleated polychromatic erythrocytes. In assessing micronuclei in normochromatic erythrocytes (NCE) of the peripheral blood, providing information on DNA integrity, there were no significant differences in micronucleus frequencies between RF-exposed and sham-exposed mice, both in peripheral blood polychromatic and normochromatic erythrocytes.

Conclusion
Regardless of frequency or maximal whole-body-averaged SAR, the lack of an RF-mediated increase in the incidence of micronucleus provides evidence against an acute, delayed, or chronic genotoxic effect in peripheral blood erythrocytes, following whole-body RF-exposure in B6C3F1 mice.


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