Study type: Medical/biological study (experimental study)

Measurement of DNA damage after acute exposure to pulsed-wave 2450 MHz microwaves in rat brain cells by two alkaline comet assay methods. med./bio.

Published in: Int J Radiat Biol 2004; 80 (1): 11-20

Aim of study (acc. to author)

To study the effect of 2450 MHz pulsed-wave microwaves on the induction of DNA damage in brain cells of exposed rats and to discover whether proteinase K is needed to detect DNA damage in the brain cells.

Background/further details

Proteinase K treatment removes nuclear proteins thereby releasing DNA from nuclear protein associations and any DNA-protein cross-links that may have been formed, thereby causing enhanced DNA migration. Rats irradiated whole-body with 1 Gy 137caesium were used as positive controls.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2,450 MHz
Modulation type: pulsed
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 pulsed
Pulse width 2 µs
Duty cycle 0.1 %
Repetition frequency 500 Hz
Exposure setup
Exposure source
Chamber The exposure system described by Malyapa et al. [1998] was used.
Setup One rat was housed unrestricted in a Plexiglas holder within a cylindrical waveguide constructed from wire mesh [Guy et al., 1979].
Sham exposure A sham exposure was conducted.
Additional info Tuning for a circularly polarized wave was achieved by adjusting tuning stubs at the proximal end of the waveguide [Guy et al. 1979].
Parameters
Measurand Value Type Method Mass Remarks
power density 2 mW/cm² mean - - -
SAR 1.2 W/kg average over mass measured and calculated whole body -

Reference articles

  • Malyapa RS et al. (1998): DNA damage in rat brain cells after in vivo exposure to 2450 MHz electromagnetic radiation and various methods of euthanasia.
  • Lai H et al. (1996): Single- and double-strand DNA breaks in rat brain cells after acute exposure to radiofrequency electromagnetic radiation.
  • 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)

Significant DNA damage was found in the brain cells of rats exposed to gamma rays using both versions of the alkaline comet assay independent of the presence or absence of proteinase K. However, neither version of the assay could detect any difference in comet length and/or normalized comet moment between sham- and 2450 MHz pulsed-wave microwave-exposed animals, regardless of the inclusion or omission of proteinase K in the comet assay.

Study character:

Study funded by

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