Study type: Medical/biological study (experimental study)

Adaptive Response in Mice Exposed to 900 MHz Radiofrequency Fields: Primary DNA Damage. med./bio.

Published in: PLoS One 2012; 7 (2): e32040

Aim of study (acc. to author)

To evaluate the extent of a primary DNA damage in peripheral blood leukocyte in mice pre-exposed to 900 MHz radiofrequency (120 mW/cm²) for 4 hours/day for different days (as adaptive dose) and then subjected to 3 Gy gamma radiation (as challenge dose).

Background/further details

Adaptive response: It is known that different cell types that were exposed to an extremely small adaptation dose of a genotoxic agent are less susceptible to the induction of genetic damage when given a higher challenge dose of the same or similar genotoxic agent. The induction of an adaptive response was shown to be influenced by several factors (e.g. the dose used for adaptation, the dose rate, the time between the adaptation and challenge doses).
Mice were divided into several groups of 5 mice each: (1) unexposed controls, (2) acute exposure to gamma radiation (3 Gy, 60Co), (3) 900 MHz radiofrequency exposure for 4 hours/day for 1, 3, 5, 7 and 14 days, and (5) the same radiofrequency exposure periods + 3 Gy gamma radiation given at 4 hour after radiofrequency exposure on days 1, 3, 5, 7 and 14.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Exposure duration: continuous for 4 hours/day for 1, 3, 5, 7 and 14 days

General information

Mice were divided into several groups of 5 mice each: (1) unexposed controls (2) acute exposure to gamma radiation (3 Gy, 60Co) (3) 900 MHz radiofrequency exposure for 4 hours/day for 1, 3, 5, 7 and 14 days (five groups) (4) the same radiofrequency exposure periods + 3 Gy gamma radiation given at 4 hour after radiofrequency exposure on days 1, 3, 5, 7 and 14 (five groups)

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 4 hours/day for 1, 3, 5, 7 and 14 days
Exposure setup
Exposure source
Setup mice were restrained and exposed individually in small plastic boxes
Parameters
Measurand Value Type Method Mass Remarks
power density 120 µW/cm² - - - -
SAR 548 mW/kg - calculated - -

Reference articles

  • Cao Y et al. (2011): Induction of adaptive response: pre-exposure of mice to 900 MHz radiofrequency fields reduces hematopoietic damage caused by subsequent exposure to ionising radiation.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data showed that the extent of DNA damage in mice which were pre-exposed to radiofrequency for 1 day and then subjected to gamma radiation was not significantly different from those animals exposed to gamma radiation alone. However, mice which were pre-exposed to radiofrequency for 3, 5, 7 and 14 days showed a progressively decreased DNA damage and the data were significantly different from those mice exposed to gamma radiation alone.
Thus, the findings indicate that radiofrequency pre-exposure is capable to induce an adaptive response and that the pre-exposure for more than 4 hours for 1 day is necessary to elicit such an adaptive response.

Study character:

Study funded by

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