Study type: Medical/biological study (experimental study)

Exposure of rat brain to 915 MHz GSM microwaves induces changes in gene expression but not double stranded DNA breaks or effects on chromatin conformation. med./bio.

Published in: Bioelectromagnetics 2006; 27 (4): 295-306

Aim of study (acc. to author)

To study whether exposure of rat brain to microwaves of global system for mobile communication (GSM) induces DNA strand breaks, changes in chromatin conformation and in gene expression.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 915 MHz
Modulation type: pulsed
Exposure duration: continuous for 2 h
  • power: 2 W peak value
  • SAR: 0.4 mW/g average over mass (whole body)

Exposure 1

Main characteristics
Frequency 915 MHz
Type
Exposure duration continuous for 2 h
Modulation
Modulation type pulsed
Pulse width 577 µs
Duty cycle 12.5 %
Repetition frequency 217 Hz
Additional info

The signal included all standard GSM modulations. (?) No voice modulation was applied, and the discontinuous transmission mode (DTX) was off.

Exposure setup
Exposure source
Chamber The output of a GSM900 test mobile phone was connected by coaxial cable to a TEM cell which has been described previously in the reference article. In principle, this is a spliced coaxial cable with a central electrode and an outer shield electrode with the unique characteristic of having both linear amplitude and phase response versus frequency and allowing relatively homogeneous exposures of samples.
Setup Rats were not restrained during exposure inside the TEM cell. The power of the test phone was kept constant at 33 dBm (2 W) and monitored online using a power meter.
Additional info Sham exposures were performed in the same TEM cell with MW power off. The order of four independent MW and sham exposures was randomized among sessions on four consecutive days.
Parameters
Measurand Value Type Method Mass Remarks
power 2 W peak value measured - -
SAR 0.4 mW/g average over mass measured and calculated whole body -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Effects of microwave exposure were found on neither conformation of chromatin nor DNA double-strand breaks.
In cerebellum from all exposed animals, 11 genes were upregulated in a range of 1.34-2.74 fold and one gene was downregulated 0.48-fold. The induced genes encode proteins with diverse functions including neurotransmitter regulation, blood-brain barrier, and melatonin production.
The results show that GSM microwaves at 915 MHz did not induce DNA double-strand breaks or changes in chromatin conformation, but affected gene expression in rat brain cells.
Because the nonthermal effects of microwaves appear to be dependent of many physical and biological variables, the data of this study should be compared with care with other studies where these variables are different.

Study character:

Study funded by

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