Study type: Medical/biological study (experimental study)

Absence of DNA damage after 60-Hz electromagnetic field exposure combined with ionizing radiation, hydrogen peroxide, or c-Myc overexpression. med./bio.

Published in: Radiat Environ Biophys 2014; 53 (1): 93-101

Aim of study (acc. to author)

To investigate whether exposure to a 60 Hz-magnetic field alone or in combination with ionizing radiation, hydrogen peroxide or c-Myc overexpression induces a DNA damage in different cell lines.

Background/further details

In a previous study, the authors showed that magnetic field exposure alone or in combination with ionizing radiation, hydrogen peroxide or c-Myc overexpression did not increase the number of micronuclei and therefore did not induce a chromosomal damage (Jin et al. 2012 ). To test whether these treatments induce a primary DNA damage, in this study the comet assay was performed.
Different experiments were performed: 1.) magnetic field exposure or sham exposure, 2.) magnetic field exposure + ionizing radiation (1 Gy), 3.) magnetic field exposure + hydrogen peroxide (50 µM) and 4.) magnetic field exposure + c-Myc overexpression.
For c-Myc overexpression, cells were transfected with a c-Myc-containing vector or with an empty vector.
Exposure to the magnetic field was performed before or after the other treatments.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 4 or 16 hours

General information

Different experiments were performed: 1.) magnetic field exposure or sham exposure, 2.) magnetic field exposure + ionizing radiation (1 Gy), 3.) magnetic field exposure + hydrogen peroxide (50 µM) and 4.) magnetic field exposure + c-Myc overexpression.

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 4 or 16 hours
Exposure setup
Exposure source
Setup a Merrit coil configuration consisting of four square coils (26 turns in the outer coils and 11 turns in the inner coils) was used; conducting wire of the coils had a diameter of 0.0014 mm; incubator consisted of three floors (upper, middle, bottom); temperature was maintained at 37 ± 0.3 °C; cells in 60-mm petri dishes were placed in the center of the floors; spatial variation of the magnetic field was less than 3%; magnetic field shielding system (made from ferrite material) was adopted to block strong magnetic fields from outside
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - calculated - at the center of the incubator

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

In the first experiment, no significant differences were observed between exposed and sham exposed cell cultures. Moreover, no synergistic effects were observed when magnetic field exposure was combined with ionizing radiation, hydrogen peroxide, or overexpression of c-Myc.
The data confirm the results of the previous study: Exposure to a 60 Hz-magnetic field alone and in combination with ionizing radiation, hydrogen peroxide or c-Myc overexpression did not induce a primary DNA damage in different cell lines.

Study character:

Study funded by

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