Microglial activation as a measure of stress in mouse brains exposed acutely (60 minutes) and long-term (2 years) to mobile telephone radiofrequency fields.
OBJECTIVE
To determine whether acute or long-term exposure of the brain to mobile telephone radiofrequency (RF) fields produces activation of microglia, which normally respond rapidly to any change in their microenvironment.


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 (SAR) of 4 W/kg for 60 min (acute) or on five successive days per week for 104 weeks (long-term). Control mice were sham-exposed or freely mobile in a cage to control for any stress caused by immobilisation in the exposure module. Positive control brains subjected to a stab wound were also included to confirm the ability of microglia to react to any neural stress. Brains were perfusion-fixed with 4% paraformaldehyde and representative regions of the cerebral cortex and hippocampus immunostained for ionised calcium binding adaptor molecule (Iba1), a specific microglial marker.


RESULTS
There was no increase in microglial Iba1 expression in brains short or long-term exposed to mobile telephony microwaves compared to control (sham-exposed or freely moving caged mice) brains, while substantial microglial activation occurred in damaged positive control neural tissue.


CONCLUSIONS
Acute (60 minutes) or longer duration (2 years) exposure of murine brains to mobile telephone RF fields did not produce any microglial activation detectable by Iba1 immunostaining.
Finnie
John W
JW
Hanson Institute Centre for Neurological Diseases, Institute of Medical and Veterinary Science, SA Pathology, Adelaide, South Australia.
Cai
Zhao
Z
Manavis
Jim
J
Helps
Stephen
S
Blumbergs
Peter C
PC
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D040421:Cell Phone; D004195:Disease Models, Animal; D019084:Fluorescent Antibody Technique, Indirect; D007124:Immunoenzyme Techniques; D051379:Mice; D008840:Microfilament Proteins; D017628:Microglia / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D011846:Radio Waves / Q000009:adverse effects*
C491049:Aif1 protein, mouse; D015415:Biomarkers; D002135:Calcium-Binding Proteins; D008840:Microfilament Proteins