Medical/biological study (experimental study)

DNA damage and apoptosis in the immature mouse cerebellum after acute exposure to a 1 mT, 60 Hz magnetic field med./bio.

By: McNamee JP, Bellier PV, McLean JR, Marro L, Gajda GB, Thansandote A

Published in: Mutat Res Genet Toxicol Environ Mutagen 2002; 513 (1-2): 121-133

Aim of study (acc. to author)

To study whether an acute 2 h exposure of a magnetic field (1 mT, 60 Hz) could elicit DNA damage, and subsequently apoptosis, in the brains of immature (10 days old) mice.

Background/further details

Mice in the positive control group were exposed to X-rays (0-3 Gy).

Endpoint

genotoxicity/mutation: DNA damage

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 2 h	magnetic flux density: 1 mT mean

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 2 h

Exposure setup

Exposure source	Merritt coils
Setup	4 x 4-coil Merritt sets; coil set consisting of four 40 cm x 40 cm square coils with 84 x 36 x 36 x 84 turns of AWG12 bifiliar copper wire; animals housed in 34 cm x 20cm x 13 cm plastic cages in the middle of chamber
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	1 mT	mean	measured	-	-

Additional parameter details

Magnetic field was measured to be 179 µT under sham exposure.

Measurement and calculation details

Magnetic field was measured with a EMDEX 2 meters.

Exposed system:

animal
mouse/ICR
whole body

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: DNA damage (alkaline Comet assay; tail ratio (relative fluorescence intensity in the comet tail region to that in the entire comet), tail moment, comet length (entire length of comet), tail length)
cell viability/cell division/proliferation: apoptosis (TUNEL assay)
effects on the neurological system: DNA damage and apoptosis in mice brains (see "genotoxicity/mutation" and "cell viability/cell division/proliferation")

Investigated system:

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

While increased DNA damage was detected by tail ratio at 2 h after magnetic field exposure, no supporting evidence of increased DNA damage was detected by the other parameters. Additionally, no similar differences were revealed using these parameters at any of the other post-exposure times (0, 4, or 24 h).
No increase in apoptosis was found in the external granule cell layer (known to undergo apoptosis caused by a variety of genotoxic chemicals and ionizing radiation) of the cerebellum of exposed mice, when compared to sham exposed mice.
These data do not support the hypothesis that acute magnetic field exposure causes DNA damage in the cerebellums of immature mice.

Study character:

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

Study funded by

not stated/no funding

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