Study type: Medical/biological study (experimental study)

Magnetic-field-induced DNA strand breaks in brain cells of the rat. med./bio.

Published in: Environ Health Perspect 2004; 112 (6): 687-694

Aim of study (acc. to author)

To investigate the effects of a 60 Hz magnetic field exposure on brain cell DNA in the rat.

Background/further details

Male rats (8/group) were exposed and additionally treated with the free radical scavenger Trolox (a vitamin E analog), the nitric oxide synthase inhibitor 7-nitroindazole and the iron chelator deferiprone to investigate their role on magnetic field induced DNA damage.
In another treatment group the effects of an acute (2 hours at 0.5 mT) magnetic field exposure on apoptosis and necrosis in rat brain cells were examined.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 24 h
Exposure 2: 60 Hz
Exposure duration: continuous for 48 h
Exposure 3: 60 Hz
Exposure duration: continuous for 2 h

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration continuous for 24 h
Additional info Reference article: Lai H, Horita A, Guy AW. 1993. Effects of a 60 Hz magnetic field on central cholinergic systems of the rat. Bioelectromagnetics 14: 5-15.
Exposure setup
Exposure source
Setup Up to three rats were exposed at a time while being housed in a plastic cage (45 cm x 21 cm x 22 cm lwh) which was placed at the center of the coils.
Additional info Controls were exposed at the bucking mode for the same period of time.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 10 µT - measured - -

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration continuous for 48 h
Exposure setup
Exposure source
Additional info Controls were exposed at the bucking mode for the same period of time.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 10 µT - measured - -

Exposure 3

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration continuous for 2 h
Additional info Reference article: Lai H, Singh NP. 1997 a. Acute exposure to 60 Hz magnetic field increases DNA strand breaks in rat brain cells. Bioelectromagnetics 18: 156-165.
Exposure setup
Exposure source
Additional info Controls were exposed at the bucking mode for the same period of time.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 500 µT - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The exposure to a 60 Hz magnetic field caused a significant increase in DNA single-strand breaks and in DNA double-strand breaks. Prolonging the exposure to 48 hours caused a larger increase.
The acute magnetic field exposure also increased apoptosis and necrosis of brain cells in the rat.
The treatment with Trolox or 7-nitroindazole blocked the magnetic field-induced DNA strand breaks. These data further support a role of free radicals on the magnetic field induced DNA damage (cf. publication 1268).
The treatment with the iron chelator also blocked the effects of magnetic fields on brain cell DNA.
These findings suggest that the exposure to a 60 Hz magnetic field initiates an iron-mediated process (e.g., the Fenton reaction) that increases free radical formation in brain cells, leading to DNA strand breaks and cell death.

Study character:

Study funded by

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