Study type: Medical/biological study (experimental study)

Expression of HSP72 after ELF-EMF exposure in three cell lines. med./bio.

Published in: Bioelectromagnetics 2007; 28 (7): 509-518

Aim of study (acc. to author)

To study the effects of different electromagnetic field exposure applications on various cell lines and to look not only at the expression of heat shock protein mRNA but also on protein levels.

Background/further details

To validate the analytical methods used, the induction of HSP72 mRNA and HSP72 protein levels in HL-60 cells after heat stress (39-45°C, 30 min) was determined.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 15 - 30 min
Exposure 2: 50 Hz
Exposure duration: 30 min

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration 15 - 30 min
Exposure setup
Exposure source
Setup pair of Helmholtz-coils with a diameter of 140 mm, 70 mm apart; each coil with 112 turns of 0.5 mm copper wire; petri dishes placed in the center of the coils, shielded with a 2 mm thick sheet of styro foam; homogenous vertical magnetic field (< 5 %) within a cylindrical volume with a diameter of 30 mm and a height of 40 mm determined from the center of the coils
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.01 mT minimum measured - -
magnetic flux density 4 mT maximum measured - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration 30 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 10 µT effective value measured - -
magnetic flux density 2 µT effective value measured - 2 - 10 µT

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data showed that these cell lines after magnetic field exposure in the milli Tesla range for 15 min reacted with an increase of HSP72 mRNA exhibiting very similar kinetics.
At the protein level there was no evidence of increased HSP72 protein production after magnetic field exposure, despite the fact that obviously in all three cell lines the corresponding mRNA could be influenced. Only in HL-60 cells there was a slight tendency for increased HSP72 levels after 1-2 h.
These results indicate that transcriptional activation of the HSP72 gene is independent of protein synthesis. Because some previous studies showed inducibility of HSP70 by electromagnetic field exposure even on a protein basis whereas other did not, it seems necessary to further investigate other factors that may play a role in the induction process of Hsp70 as well.

Study character:

Study funded by

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