Study type: Medical/biological study (experimental study)

Non-thermal effects of power-line magnetic fields (50 Hz) on gene expression levels of pluripotent embryonic stem cells-the role of tumour suppressor p53. med./bio.

Published in: Mutat Res Genet Toxicol Environ Mutagen 2004; 557 (1): 63-74

Aim of study (acc. to author)

This in vitro study was performed to investigate the effects of non-thermal extremely low frequency electromagnetic fields on gene expression in murine embryonic stem cells.

Background/further details

Embryonic stem cells were chosen as model to explore cell differentiation.
Besides the influence of the cellular p53 status the effects of an intermittent or continuous exposure with/without recovery time at different magnetic flux densities should be examined.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: intermittent for 6 h or 48 h, 5 min on/30 min off
Exposure 2: 50 Hz
Exposure duration: intermittent for 6 h or 48 h, 5 min on/10 min off
Exposure 3: 50 Hz
Exposure duration: continuous for 6 or 48 h

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration intermittent for 6 h or 48 h, 5 min on/30 min off
Exposure setup
Exposure source
Setup Two four coil systems, each placed inside a µ-metal shielding box. The coils generated a linearly polarized B-field the area of the Petri dishes with the B-field vector perpendicular to the dish plane. The B-field was homogeneous over the exposure area (16 cm x 16 cm 16 cm). For sham exposure, the currents in the bifilar coils were switched non-parallel.
Additional info B-field vector perpendicular to the Petri dishes plane. One chamber was used for exposure and the other one used for sham exposure.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT unspecified measured - -
magnetic flux density 100 µT unspecified measured - -
magnetic flux density 2.3 mT unspecified measured - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration intermittent for 6 h or 48 h, 5 min on/10 min off
Exposure setup
Exposure source
  • same setup as exposure 1
  • two four coil systems, each placed inside a µ-metal shielding box.
Chamber µ-metal shielding chambers
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2.3 mT unspecified measured - -

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 6 or 48 h
Exposure setup
Exposure source
  • same setup as exposure 1
  • two four coil systems, each placed inside a µ-metal shielding box.
Chamber µ-metal shielding chambers
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 µT unspecified measured - -
magnetic flux density 1 mT unspecified measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The intermittent magnetic field exposure ("5 minutes "field-on"/30 minutes "field-off" cycles" at a magnetic flux density of 2.3 mT for 6 hours) showed a significant up-regulation of c-jun, p21 and egr-1 mRNA levels in p53-deficient, but not in wild type cells.
No significant effects were observed in both cell lines exposed to magnetic fields at lower magnetic flux densities, longer exposure time or after 18 hours recovery time.

Study character:

Study funded by

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