Study type: Medical/biological study (experimental study)

50-Hz magnetic field induces EGF-receptor clustering and activates RAS med./bio.

By: Ke XQ, Sun WJ, Lu DQ, Fu YT, Chiang H
Published in: Int J Radiat Biol 2008; 84 (5): 413-420
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Aim of study (acc. to author)

In this study the effects of extremely low frequency magnetic fields exposure on clustering of epidermal growth factor receptors (EGFR) and Ras protein activation should be investigated.

Background/further details

Cells treated with 100 ng/ml epidermal growth factor (EGF) were the positive controls. The investigated Ras-protein is a proto-oncogene which plays important role in signal transduction pathways.
The experiments were repeated at least three times.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 5 min, 15 min or 30 min
Exposure 2: 30–90 Hz
Exposure duration: continuous for 15 min or 30 min
Exposure 3: 30–90 Hz
Exposure duration: continuous for 15 min or 30 min

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 5 min, 15 min or 30 min
Exposure setup
Exposure source
Setup 3 groups of square copper coils (36 cm x 36 cm) with 168, 60, 168 turns (upper, middle, lower coils), connected in series and spaced 8 cm apart, placed in an iron metal container; culture dishes placed inside the coil system
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT - measured - -

Exposure 2

Main characteristics
Frequency 30–90 Hz
Type
Exposure duration continuous for 15 min or 30 min
Additional info white noise
Exposure setup
Exposure source
Setup 3 groups of square copper coils (36 cm x 36 cm) double-wrapped with two lines of copper wire, placed in an iron metal container; culture dishes placed inside the coil system
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT mean measured - -

Exposure 3

Main characteristics
Frequency 30–90 Hz
Type
Waveform
Exposure duration continuous for 15 min or 30 min
Additional info 30 Hz - 90 Hz white noise + 50 Hz sinusoidal
Exposure setup
Exposure source
Setup 3 groups of square copper coils (36 cm x 36 cm) double-wrapped with two lines of copper wire, placed in an iron metal container; culture dishes placed inside the coil system
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT - measured - -

Reference articles

  • Zeng Q et al. (2006): Noise magnetic fields abolish the gap junction intercellular communication suppression induced by 50 Hz magnetic fields

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The exposure to 50 Hz magnetic field alone for 5 minutes slightly caused epidermal growth factor receptor clustering, whereas the magnetic field exposure for 15 minutes enhanced receptor clustering significantly. The Ras protein was also activated after 50 Hz magnetic field exposure alone.
The exposure to the noise magnetic field alone at the same intensity and durations, showed no significant effect on EGF receptor clustering and Ras protein. However, by superimposing the noise magnetic field, receptor clustering and Ras activation induced by 50 Hz magnetic field were inhibited.
These data suggest that membrane receptors could be one of the most important targets where extremely low frequency magnetic field interacts with cells, and Ras may participate in the signal transduction process of 50 Hz magnetic field. Furthermore, a noise magnetic field could inhibit these effects.

Study character:

Study funded by

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