Study type: Medical/biological study (experimental study)

Mobile phone base station-emitted radiation does not induce phosphorylation of Hsp27. med./bio.

Published in: Bioelectromagnetics 2007; 28 (2): 99-108

Aim of study (acc. to author)

To determine whether non-thermal exposure of cultured cells to 2.1425 GHz continuous wave (CW) and W-CDMA modulated signal radiofrequency fields (of a mobile radio base station) induces phosphorylation of hsp27.

Background/further details

Phosphorylation of hsp27 occurs following exposure to various stresses and phosphorylation is suggested to be important for hsp27 function.
Positive controls were performed at 42°C (2 h) or at 43°C (3 h).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.1425 GHz
Exposure duration: continuous for 2, 24, or 48 h for A172 cells
Exposure 2: 2.1425 GHz
Exposure duration: continuous for 2 or 28 h for IMR-90 cells
Exposure 3: 2.1425 GHz
Modulation type: CW
Exposure duration: continuous for 24 or 48 h for A172 cells
Exposure 4: 2.1425 GHz
Modulation type: CW
Exposure duration: continuous for 28 h for IMR-90 cells

Exposure 1

Main characteristics
Frequency 2.1425 GHz
Type
Exposure duration continuous for 2, 24, or 48 h for A172 cells
Modulation
Modulation type cf. additional info
Additional info

The W-CDMA component of the IMT-2000 cellular system adopts Direct Sequence CDMA (DSCDMA) and Frequency Division Duplex (FDD) as a multiple access and duplex scheme, respectively. The chip rate of the spread code of this system is 3.84 Mcps.

Exposure setup
Exposure source
Chamber A beam-formed RF exposure incubator employing a horn antenna, a dielectric lens, and a culture case in an anechoic chamber was developed for large-scale in vitro studies [Iyama et al., 2004].
Setup This system allowed simultaneous exposure of 49 (7 x 7 array) 35-mm culture dishes with a uniform SAR distribution in the medium. Nine of the inner 25 culture dishes (5 x 5 array) were used in this study.
Sham exposure A sham exposure was conducted.
Additional info Two identical incubators in separate anechoic chambers were provided with identical air through sealed ducts at 37.0 °C, 5.0% CO2, and >90% humidity. They were selected blindly for RF or sham exposure by a mechanical switch in a dummy box.
Parameters
Measurand Value Type Method Mass Remarks
SAR 80 mW/kg mean unspecified - -
SAR 250 mW/kg mean unspecified - 24 or 48 h only
SAR 800 mW/kg mean unspecified - -

Exposure 2

Main characteristics
Frequency 2.1425 GHz
Type
Exposure duration continuous for 2 or 28 h for IMR-90 cells
Modulation
Modulation type cf. additional info
Additional info

same as E1

Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 80 mW/kg mean unspecified - -
SAR 800 mW/kg mean unspecified - -

Exposure 3

Main characteristics
Frequency 2.1425 GHz
Type
Exposure duration continuous for 24 or 48 h for A172 cells
Modulation
Modulation type CW
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 80 mW/kg mean unspecified - -

Exposure 4

Main characteristics
Frequency 2.1425 GHz
Type
Exposure duration continuous for 28 h for IMR-90 cells
Modulation
Modulation type CW
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 80 mW/kg mean unspecified - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated material:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data suggest that radiofrequency exposure at a SAR of the mobile radio base station level does not affect the stress response pathways following hsp27 phosphorylation.
No significant differences in the expression levels of phosphorylated hsp27 were found between the groups exposed to W-CDMA or CW signal and the sham-exposed negative controls. Moreover, no noticeable differences in the hsp gene expression were observed between the exposed groups and the negative controls by microarray analysis.

Study character:

Study funded by

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