Medical/biological study (experimental study)

Extremely low frequency magnetic fields cause oxidative DNA damage in rats med./bio.

By: Yokus B, Akdag Z, Dasdag S, Cakir DU, Kizil M

Published in: Int J Radiat Biol 2008; 84 (10): 789-795

Aim of study (acc. to author)

To detect the genotoxic effects (oxidative DNA base modifications) of extremely low frequency magnetic fields in rat leukocytes.

Background/further details

The following modified DNA bases generated by free radicals were investigated: 8-hydroxy-guanine (8-OH-Gua); 2,6-diamino-4-hydroxy-5-formamido-pyrimidine (FapyGua) and 4,6-diamino-5-formamido-pyrimidine (FapyAde).
13 rats were randomly divided into four groups: two experimental groups (n=3 and n=4), a sham exposed group and a cage control. In the experiments a 50 Hz exposure by 100 µT and 500 µT was chosen, because these are the limit values set for public and occupational exposure by ICNIRP.

Endpoint

genotoxicity/mutation: oxidative DNA base modifications

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 2 h/day for 10 months	magnetic flux density: 100 µT magnetic flux density: 500 µT

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	continuous for 2 h/day for 10 months

Exposure setup

Exposure source	coil(s)
Setup	Pair of Helmholtz coils with a diameter of 25 cm, consisting of 225 turns of 1.0 mm insulated copper wire wound on frames of wood and aluminum; coils 25 cm apart, placed horizontally inside a 130 cm x 65 cm x 80 cm Faraday cage; rats kept in 17 cm x 17 cm x 25 cm methacrylate cages inside the coil system
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	100 µT	-	measured	-	-
magnetic flux density	500 µT	-	measured	-	-

Exposed system:

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: oxidative DNA base modifications: 8-OH-Gua, FapyGua, FapyAde (gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry)

Investigated system:

DNA/RNA

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Levels of FapyAde, FapyGua and 8-OH-Gua in DNA were increased by both 100 µT and 500 µT extremely low frequency magnetic field as compared to cage control and sham exposure group. Statistical significance was observed only in the group exposed to 100 µT.
This is the first study to report that exposure to extremely low frequency magnetic field generated oxidatively induced DNA base modifications in vivo. The findings support the hypothesis that chronic exposure to 50 Hz magnetic fields may be potentially genotoxic.

Study character:

medical/biological study
experimental study
full/main study
blind study

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