Expression of the water channel protein, aquaporin-4, in mouse brains exposed to mobile telephone radiofrequency fields.
OBJECTIVE
To determine whether exposure to mobile telephone radiofrequency (RF) fields, either acutely or long-term, produces up-regulation of the water channel protein, aquaporin-4 (AQP-4).


METHODS
Using a purpose-designed exposure system at 900 MHz, mice were given a single, far-field whole body exposure at a specific absorption rate of 4 W/kg for 60 minutes or a similar exposure on 5 successive days/week for 104 weeks. Control mice were sham-exposed or freely mobile in a cage to control for any stress caused by restraint in the exposure module. A positive control group was given a clostridial toxin known to cause microvascular endothelial injury, severe vasogenic oedema and upregulation of AQP-4. Brains were perfusion fixed with 4% paraformaldehyde, coronal sections cut from six levels, and immunostained for the principal water channel protein in brain, AQP-4.


RESULTS
There was no increase in AQP-4 expression in brains exposed to mobile phone microwaves compared to control (sham exposed and freely moving caged mice) brains after short or protracted exposure, while AQP-4 was substantially upregulated in the brains of mice given the clostridial toxin.


CONCLUSIONS
Brains exposed to mobile telephone RF fields for a short (60 minutes) or long (2 years) duration did not show any immunohistochemically detectable up-regulation of the water channel protein, AQP-4, suggesting that there was no significant increase in blood-brain barrier permeability
Finnie
John W
JW
Hanson Institute Centre for Neurological Diseases, Institute of Medical and Veterinary Science, Adelaide, South Australia.
Blumbergs
Peter C
PC
Cai
Zhao
Z
Manavis
Jim
J
D000818:Animals; D051401:Aquaporin 4 / Q000528:radiation effects*; D001921:Brain / Q000378:metabolism / Q000528:radiation effects*; D040421:Cell Phone; D007150:Immunohistochemistry; D051379:Mice; D011846:Radio Waves / Q000009:adverse effects*
C496031:Aqp4 protein, mouse; D051401:Aquaporin 4