Study type: Medical/biological study (experimental study)

Interaction of Microwaves and a Temporally Incoherent Magnetic Field on Single and Double DNA Strand Breaks in Rat Brain Cells. med./bio.

Published in: Electromagn Biol Med 2005; 24 (1): 23-29

Aim of study (acc. to author)

To study whether simultaneous exposure to a temporally incoherent magnetic field ("noise") could attenuate microwave-induced increases in DNA single-strand breaks and double-strand breaks in brain cells of the rat.

Background/further details

Four treatment groups of rats were investigated: microwave-exposure, noise-exposure (45 mG), microwave + noise-exposure, and sham-exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2,450 MHz
Modulation type: CW
Exposure duration: continuous for 2 h
  • power density: 1 mW/cm²
  • SAR: 0.6 W/kg average over mass (whole body) ([Chou et al., 1984])
Exposure 2: 30–100 Hz
Exposure duration: continuous for 2 h

General information

Animals were exposed to MW alone, MW plus noise, and noise alone. A sham-exposed animal was included in each run.

Exposure 1

Main characteristics
Frequency 2,450 MHz
Type
Charakteristic
  • guided field
Polarization
  • circular
Exposure duration continuous for 2 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Setup Cylindrical waveguides made of galvanized wire screen were excited in TE11 mode [Guy et al., 1979]. Each waveguide contained a plastic chamber to house a rat with enough space to move and a floor made of glass rods.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 1 mW/cm² - - - -
SAR 0.6 W/kg average over mass cf. remarks whole body [Chou et al., 1984]

Exposure 2

Main characteristics
Frequency 30–100 Hz
Type
Exposure duration continuous for 2 h
Additional info band-limited ELF noise
Modulation
Modulation type cf. additional info
Additional info

The incoherent magnetic field (ELF noise) was generated using a signal recorded in an audiocassette tape.

Exposure setup
Exposure source
Setup For incoherent magnetic field exposure, a waveguide was placed between a pair of Helmholtz coils which were positioned across the plastic cage. E-field shielding was provided by connecting the coil frame made of flexible copper tubing to electrical ground.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 4.5 µT mean measured - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Data show that brain cells of microwave-exposed rats had significantly higher levels of DNA single-strand breaks and double-strand breaks when compared with sham-exposed animals. Exposure to noise alone did not significantly affect the levels. However, simultaneous noise exposure blocked microwave-induced increases in DNA strand breaks.
These findings indicate that simultaneous exposure to a temporally incoherent magnetic field could block microwave-induced DNA damage in brain cells of the rat.

Study character:

Study funded by

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