title: Microglial activation as a measure of stress in mouse brains exposed acutely (60 minutes) and long-term (2 years) to mobile telephone radiofrequency fields.
abstract: 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.
authors.affiliation: Hanson Institute Centre for Neurological Diseases, Institute of Medical and Veterinary Science, SA Pathology, Adelaide, South Australia.
authors.forename: John W
authors.initials: JW
authors.lastname: Finnie
authors.forename: Zhao
authors.initials: Z
authors.lastname: Cai
authors.forename: Jim
authors.initials: J
authors.lastname: Manavis
authors.forename: Stephen
authors.initials: S
authors.lastname: Helps
authors.forename: Peter C
authors.initials: PC
authors.lastname: Blumbergs
mesh_terms: 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*
chemical_list: C491049:Aif1 protein, mouse; D015415:Biomarkers; D002135:Calcium-Binding Proteins; D008840:Microfilament Proteins