Study type: Medical/biological study (experimental study)

DNA fragmentation in human fibroblasts under extremely low frequency electromagnetic field exposure. med./bio.

Published in: Mutation Research - Fundamental and Molecular Mechanism of Mutagenesis 2010; 683 (1-2): 74-83

Aim of study (acc. to author)

The aim of the study was to replicate previous studies by Ivancsits et al. (Ivancsits et al. 2002, Ivancsits et al. 2003), implicating an increase of DNA strand breaks in primary human fibroblasts intermittently exposed to 50 Hz extremely low frequency electromagnetic fields (ELF-EMF). The aim of the present work was to test the reproducibility of these observations and to explore the origin and nature of the ELF-EMF induced DNA effects (identical experimental conditions and procedures were applied).

Background/further details

Hydrogen peroxide treatment was used to study oxidative stress induced DNA damage.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 5 min on - 10 min off - for 15 hr
Exposure 2: 50 Hz
Exposure duration: continuous for 15 hr

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration 5 min on - 10 min off - for 15 hr
Additional info with frequency components up to 1 kHz
Exposure setup
Exposure source
Setup four-coil system consisting of bifilar coils placed in a µ-metal box inside an incubator
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - - - -
electric field strength 33.2 mV/m maximum measured - induced field at the edge of a 10 cm petri dish
electric field strength 0 mV/m - measured - in the center of the petri dish

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 15 hr
Additional info with frequency components up to 1 kHz
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - - - -
electric field strength 33.2 mV/m maximum measured - induced field at the edge of a 10 cm petri dish
electric field strength 0 mV/m - measured - in the center of the petri dish

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated material:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data confirmed that intermittent (but not continuous) exposure of human primary fibroblasts to a 50 Hz electromagnetic field (at a magnetic flux density of 1 mT) induces a slight but significant increase of DNA fragmentation in the Comet assay. The authors provide first evidence for this to be caused by the magnetic field rather than the electric field (for this purpose cells of the central and peripheral areas of the Petri dishes were compared). Moreover, the authors showed that electromagnetic field-induced responses in the Comet assay were dependent on cell proliferation, suggesting that processes of DNA replication rather than the DNA itself may be affected. Consistently, the effects in the Comet assay correlated with a reduction of actively replicating cells and a concomitant increase of apoptotic cells in exposed cell cultures, whereas a combined Fpg-Comet assay failed to produce evidence for a notable contribution of oxidative DNA base damage.
Hence, ELF-EMF induced effects in the Comet assay are reproducible under specific conditions and can be explained by minor disturbances in S phase processes and occasional triggering of apoptosis rather than by the generation of DNA damage. Finally, this S phase dependency may explain issues of reproducibility of the ELF-EMF induced Comet assay effects (the fraction of S phase cells in a population is determined by the culture conditions and the cell lines used, and these parameters may vary between laboratories).

Study character:

Study funded by

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