The effects of extremely low frequency magnetic fields on mutation induction in mice

The effects of extremely low frequency magnetic fields on mutation induction in mice

Wilson JW, Haines J, Sienkiewicz Z, Dubrova YE. The effects of extremely low frequency magnetic fields on mutation induction in mice. Mutat Res. 2015 Mar;773:22-6. doi: 10.1016/j.mrfmmm.2015.01.014. Epub 2015 Jan 30.

Abstract

The growing human exposure to extremely low frequency (ELF) magnetic fields has raised a considerable concern regarding their genotoxic effects. 

The aim of this study was to evaluate the in vivo effects of ELF magnetic fields irradiation on mutation induction in the germline and somatic tissues of male mice. Seven week old BALB/c×CBA/Ca F1 hybrid males were exposed to 10, 100 or 300μT of 50Hz magnetic fields for 2 or 15h. Using single-molecule PCR, the frequency of mutation at the mouse Expanded Simple Tandem Repeat (ESTR) locus Ms6-hm was established in sperm and blood samples of exposed and matched sham-treated males. ESTR mutation frequency was also established in sperm and blood samples taken from male mice exposed to 1Gy of acute X-rays. 

The frequency of ESTR mutation in DNA samples extracted from blood of mice exposed to magnetic fields did not significantly differ from that in sham-treated controls. However, there was a marginally significant increase in mutation frequency in sperm but this was not dose-dependent. In contrast, acute exposure X-rays led to significant increases in mutation frequency in sperm and blood of exposed males. The results of our study suggest that, within the range of doses analyzed here, the in vivo mutagenic effects of ELF magnetic fields are likely to be minor if not negligible.

http://1.usa.gov/1HW5aBX

Highlights

• The effects of 50 Hz magnetic fields on mutation induction in mice were analyzed.

• The frequency of ESTR mutation was established in sperm and blood.

• Exposure to 10–300 μT for 2 and 15 h did not result in mutation induction.

• Mutagenic effects of 50 Hz magnetic fields are likely to be negligible.

Excerpts

The results of our study show that exposure to 50 Hz magnetic fields at up to 300 μT does not affect the frequency of ESTR mutation in male mice. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) provide guidelines that limit the exposure of members of the public to magnetic fields to 200 μT at 50 Hz [23]. This figure is set to avoid the possibility of acute physiological effects on the brain and nervous tissues and stimulation of muscles. The magnetic fields used in our study encompass the guideline value, although all these fields are considerably above the average exposure in homes in many countries, including the UK [6]. These fields are also well above the levels reported in epidemiological studies to increase the risk of childhood leukaemia [2.3] Although the frequency of ESTR mutation in sperm of exposed males marginally-significantly exceeds that in sham-treated animals, our data do not provide any evidence for dose-dependent increases in exposed mice (Fig. 2C). However, in the absence of a known mechanism whereby magnetic fields are able to cause mutagenic effects in mammalian tissues, the shape of the dose response cannot be predicted with certainty. According to the results of our previous studies a significant increase in ESTR mutation rate in the germline of irradiated male mice can be detected at dose of 0.5 Gy of acute X-/γ-rays [10] and [15]. The data presented here therefore suggest that the mutagenic effects of magnetic field exposure to members of the public are unlikely to cause more ESTR mutations than 0.5 Gy of X-rays.

In conclusion, our study represents the first systematic attempt to analyze simultaneously the in vivo effects of 50 Hz magnetic fields on mutation induction in the germline and somatic tissues of male mice. Although we used a highly sensitive system capable of detecting mutation induction in proliferating mouse tissues, we did not detect any significant increases in the frequency ESTR mutation in blood following exposure to magnetic fields. We found a significant level of induced mutations in germline cells but this should be treated with caution as there was no evidence of a dose response. Our results therefore suggest that mutagenic effect of magnetic fields normally experienced by members of the public are below that induced by 0.5 Gy of X-rays in germline cells.

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Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley

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