Study type: Medical/biological study (experimental study)

Exposure to power frequency magnetic fields and X-Rays induces GAP-43 gene expression in human glioma MO54 cells med./bio.

By: Ding GR, Nakahara T, Miyakoshi J
Published in: Bioelectromagnetics 2002; 23 (8): 586-591
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Aim of study (acc. to author)

To investigate the local intracellular distribution and gene expression of "growth associated protein"-43 (GAP-43) in human glioma cells after exposure to a magnetic field (60 Hz, 5 mT), with or without initial X-rays radiation (2 Gy) in vitro.

Background/further details

The investigated "growth associated protein"-43 (GAP-43) is considered to be a marker for development and growth stimulation of cells in brain tissues.
The magnetic flux density, 5 mT, used in this study is the maximum permissible under the guidelines from the "International Non-ionizing Radiation Committee of the International Radiation Protection Association" (IRPA/INIRC) for the short term occupational whole body exposure (2 hours per work day).
The experiments were repeated three times.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: 5, 10, 12 and 24 h

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Exposure duration 5, 10, 12 and 24 h
Exposure setup
Exposure source
Chamber CO2 incubator with a built-in magnet generator using two Helmholtz coils
Additional info cylindrical exposure space (14 cm height x 20 cm diameter) housing sixteen 10 or four 15 cm culture dishes; inside and outside of the incubator shielded by silicon steel and Permalloy C.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5 mT effective value measured unspecified -
Additional parameter details

The environmental 60 Hz ELF MF during sham exposure was less than 0.5 µT. Static MFs were undectable < 0.1 µT. Residual geomagnetism < 1 µT. Cells exposed each time once without X-ray and once with X-ray at 2 Gy at a dose rate of 1.1 Gy/min

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

GAP-43 was present in the cytoplasm, accumulating in the perinuclear area.
Exposure of cells to the extremely low frequency electromagnetic field for 5 hours resulted in a 2.5-fold increase in GAP-43 mRNA levels compared to sham-exposed cells. The transcription level induced by co-exposure was slightly higher than for exposure to X-rays radiation alone, but lower than that for exposure to the magnetic field alone. The kinetic pattern of GAP-43 mRNA levels in X-rays exposed cells were very similar to that in magnetic field exposed cells.
GAP-43 protein expression was about 2-fold higher after 12 hours electromagnetic field exposure compared to sham exposed cells returning to control levels after 24 hours.

Study character:

Study funded by

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