Study type: Medical/biological study (experimental study)

Effects of exposure to a 1950 MHz radio frequency field on expression of Hsp70 and Hsp27 in human glioma cells. med./bio.

Published in: Bioelectromagnetics 2005; 26 (4): 251-257

Aim of study (acc. to author)

To study whether exposure to a radiofrequency field could act as an environmental insult to invoke a stress response in human glioma cells, using HSP27 and HSP70 (different heat shock proteins) as stress markers.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1,950 MHz
Modulation type: CW
Exposure duration: continuous for 1 or 2 h
Exposure 2: 1,950 MHz
Modulation type: CW
Exposure duration: continuous for 10 or 30 min and 1 or 2 h

Exposure 1

Main characteristics
Frequency 1,950 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 1 or 2 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber The exposure apparatus consisting of two single-mode resonator cavities for 1.8 GHz (based on the R18 waveguide) was placed in an ordinary incubator.
Setup Cells cultured in 35-mm dishes were placed on dish holders in the two waveguides, one for RF and one for sham exposure. A PC randomly determined which of the two waveguides was exposed.
Sham exposure A sham exposure was conducted.
Additional info None of the exposure conditions produced a rise in temperature greater than 0.1 °C. Other cells were treated at 43 °C for 2 or 3 h as a positive control.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg - - - -
SAR 2 W/kg - - - -

Exposure 2

Main characteristics
Frequency 1,950 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 10 or 30 min and 1 or 2 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 10 W/kg - - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Sham-exposed and exposed cells demonstrated a similar growth pattern up to 4 days after exposure. Exposure at both 2 and 10 W/kg did not affect the growth of the cells. In addition, there were no significant differences in protein expression of HSP27 and HSP70 between sham-exposed and exposed cells at a SAR of 1, 2, or 10 W/kg for 1 and 2 h. However, exposure at a SAR of 10 W/kg for 1 and 2 h decreased the protein level of phosphorylated Hsp27 significantly.
The data suggest that although exposure to a 1950 MHz radiofrequency field has no effect on cell proliferation and expression of HSP27 and HSP70, it may inhibit the phosphorylation of HSP27 at serine 78 in MO54 cells (HSP27 is phosphorylated at three phosphorylation sites (serine 15, serine 78, and serine 82) by protein kinases. In this investigation, an anti-HSP27 antibody that is specific for phosphorylated HSP27 (serine 78) was used).

Study character:

Study funded by

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