Study type: Medical/biological study (experimental study)

DNA damage in rat brain cells after in vivo exposure to 2450 MHz electromagnetic radiation and various methods of euthanasia med./bio.

By: Malyapa RS, Ahern EW, Bi C, Straube WL, LaRegina MC, Pickard WF, Roti Roti JL
Published in: Radiat Res 1998; 149 (6): 637-645
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Aim of study (acc. to author)

To confirm previously reported observations (publication 1385) that low-intensity acute exposure to 2.45 GHz radiation causes DNA single-strand breaks.

Background/further details

After the exposure or sham treatments, rats were euthanized by either CO2 gassing or decapitation by guillotine.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2,450 MHz
Modulation type: CW
Exposure duration: continuous for 2 h

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
  • circular waveguide
  • made of wire mesh [Guy et al., 1979]
Setup Each rat was housed in a Plexiglas holder placed in the waveguide without restricting its position.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 2 mW/cm² mean unspecified - -
SAR 1.2 W/kg mean measured and calculated whole body -
Additional parameter details

Some rats immobilised in a plastic container were 137Cs γ irradiated with a whole-body dose of 0.5 or 2 Gy at 0.82 Gy/min and were decapitated afterwards.

Measurement and calculation details

The nominal SAR was calculated using the method of [Lai et al., 1995] and was verified by a total of eight temperature rise measurements made in three rat cadavers (180-450 g) using a 2-min burst of power [Chou et al., 1996] and yielding an average SAR of 1.9 W/kg per W input. However, the brain SAR was found to depend significantly on the orientation of the rat's nose (up to a factor of two).

Reference articles

  • Chou CK et al. (1996): Radio frequency electromagnetic exposure: tutorial review on experimental dosimetry
  • Lai H et al. (1995): Acute low-intensity microwave exposure increases DNA single-strand breaks in rat brain cells
  • Guy AW et al. (1979): Circularly polarized 2450 MHz waveguide system for chronic exposure of small animals to microwaves

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Irrespective of whether the animals were euthanized by CO2 asphyxia or decapitated by guillotine, no significant differences were observed between either the comet length or the normalized comet moment of cells from either the cerebral cortex or the hippocampus of sham-treated rats and those from the exposed rats. However, the data for the rats asphyxiated with CO2 showed more intrinsic DNA damage and more experiment-to-experiment variation than did the data for animals euthanized by guillotine. Furthermore, the authors did not confirm the observation that DNA damage is produced in cells of the rat cerebral cortex or the hippocampus after a 2-h exposure to 2450 MHz (2.45 GHz) CW microwaves or at 4 h after the exposure.

Study character:

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