Study type: Medical/biological study (experimental study)

Expression of the water channel protein, aquaporin-4, in mouse brains exposed to mobile telephone radiofrequency fields. med./bio.

Published in: Pathology 2009; 41 (5): 473-475

Aim of study (acc. to author)

To study whether acute (60 minutes) or long-term (two years) exposure to mobile phone radiofrequency fields produces up-regulation of the water channel protein, aquaporin-4.

Background/further details

Aquaporins are a family of small hydrophobic membrane proteins that serve as a selective pore through which water traverses the plasma membrane of different cell types. Aquaporin-4 is up-regulated in cerebral oedema of vasogenic type where there is increased blood-brain barrier permeability. The authors immunostained brains for aquaporin-4, which had previously been used in vascular tracer studies with albumin (Finnie et al. 2001, Finnie et al. 2002, and Finnie and Blumbergs 2004).
10 mice were acutely exposed, 10 mice were long-term exposed, 20 mice were sham-exposed and 20 mice were cage control animals (10 for each exposure condition). A positive control group was given a clostridial toxin known to cause microvascular endothelial injury, severe vasogenic oedema and up-regulation of aquaporin-4.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 60 min
Exposure 2: 900 MHz
Modulation type: pulsed
Exposure duration: continuous on 5 days/week for 104 weeks
long time exposure

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Charakteristic
Exposure duration continuous for 60 min
Additional info acute exposure
Modulation
Modulation type pulsed
Pulse width 0.6 ms
Repetition frequency 217 Hz
Exposure setup
Exposure source
Setup mice in perpex tubes arrangd radially around the dipole antenna
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 4 W/kg - - whole body -

Exposure 2

Main characteristics
Frequency 900 MHz
Type
Charakteristic
Exposure duration continuous on 5 days/week for 104 weeks
Additional info long time exposure
Modulation
Modulation type pulsed
Pulse width 0.6 ms
Repetition frequency 217 Hz
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 4 W/kg - - 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)

There was no increase in aquaporin-4 expression in mouse brains exposed to mobile phone microwaves compared to controls (sham exposure and cage control) brains after short or long-term exposure, while aquaporin-4 was substantially upregulated in the brains of mice given the clostridial toxin.
The authors conclude that brains exposed to mobile phone radiofrequency fields for a short or long duration did not show any immunohistochemically detectable up-regulation of the water channel protein, aquaporin-4, suggesting that there was no significant increase in blood-brain barrier permeability.

Study character:

Study funded by

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