Medical/biological study (experimental study)

Microglial activation as a measure of stress in mouse brains exposed acutely (60 minutes) and long-term (2 years) to mobile telephone radiofrequency fields med./bio.

By: Finnie JW, Cai Z, Manavis J, Helps S, Blumbergs PC

Published in: Pathology 2010; 42 (2): 151-154

Aim of study (acc. to author)

To study whether acute (60 min) or long-term (five days per week, 104 weeks) exposure of the mouse brain to mobile phone radiofrequency fields produces activation of microglia, which normally respond rapidly to any change in their microenvironment.

Background/further details

Microglia is considered as a specialised form in the central nervous system. In response to a variety of insults, microglia adopts an activated phenotype. Microglia activation plays a pivotal role in the initiation and progression of several neurodegenerative diseases.
30 mice were divided into three groups: 1) exposure group (n=10; remark of EMF-Portal editor: number of animals (distribution) in the acute and long-term exposure group unclear), 2) sham exposure group (n=10) and 3) cage control (n=10). Positive controls were also included (stab wound treatment).

Endpoint

effects on the neurological system: microglia activation

Exposure

- PW pulsed wave
- mobile communications
- mobile phone
- GSM

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: continuous for 60 min acute exposure	SAR: 4 W/kg
Exposure 2: 900 MHz Modulation type: pulsed Exposure duration: continuous for 5 days/week for 104 weeks long-term exposure	SAR: 4 W/kg

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Charakteristic	far field
Exposure duration	continuous for 60 min
Additional info	acute exposure

Modulation

Modulation type	pulsed
Pulse width	0.6 ms
Repetition frequency	217 Hz
Additional info	GMS like field

Exposure setup

Exposure source	dipole antenna
Setup	mice in perspex tubes arranged 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	electromagnetic field
Charakteristic	far field
Exposure duration	continuous for 5 days/week for 104 weeks
Additional info	long-term exposure

Modulation

Modulation type	pulsed
Pulse width	0.6 ms
Repetition frequency	217 Hz
Additional info	GMS like field

Exposure setup

Exposure source	same setup as exposure 1
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	4 W/kg	-	-	whole body	-

Exposed system:

animal
mouse
whole body

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: microglia activation (expression (density) of ionised calcium binding adaptor molecule (Iba1; a specific microglial marker) in the cerebral cortex and hippocampus; immunohistochemistry)

Investigated system:

tissue slices

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

There was no increase in microglial Iba1 expression in brains of short or long-term exposed mice compared to the controls (sham exposed or cage control), while substantial microglial activation occurred in damaged positive control neural tissue.
The authors conclude that an acute or longer duration exposure of murine brains to mobile phone radiofrequency electromagnetic fields did not produce any microglial activation detectable by Iba1 immunostaining.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

Australian Centre for Radiofrequency Bioeffects
National Health and Medical Research Council (NHMRC), Australia

Bouji M et al. (2016): Neurobiological effects of repeated radiofrequency exposures in male senescent rats
Son Y et al. (2015): The Effect of Sub-Chronic Whole-Body Exposure to a 1,950 MHz Electromagnetic Field on the Hippocampus in the Mouse Brain
Lu Y et al. (2014): Differential Pro-Inflammatory Responses of Astrocytes and Microglia Involve STAT3 Activation in Response to 1800 MHz Radiofrequency Fields
Maskey D et al. (2013): Neuroprotective effect of ginseng against alteration of calcium binding proteins immunoreactivity in the mice hippocampus after radiofrequency exposure
Carballo-Quintas M et al. (2011): A study of neurotoxic biomarkers, c-fos and GFAP after acute exposure to GSM radiation at 900MHz in the picrotoxin model of rat brains
Hao Y et al. (2010): STAT3 signalling pathway is involved in the activation of microglia induced by 2.45 GHz electromagnetic fields
Maskey D et al. (2010): Chronic 835-MHz radiofrequency exposure to mice hippocampus alters the distribution of calbindin and GFAP immunoreactivity
Yang X et al. (2010): The role of the JAK2-STAT3 pathway in pro-inflammatory responses of EMF-stimulated N9 microglial cells
Xiao-Feng P et al. (2005): The influence of electromagnetic field irradiated by high-voltage transmission lines on properties of cells
Mausset-Bonnefont AL et al. (2004): Acute exposure to GSM 900-MHz electromagnetic fields induces glial reactivity and biochemical modifications in the rat brain

Microglial activation as a measure of stress in mouse brains exposed acutely (60 minutes) and long-term (2 years) to mobile telephone radiofrequency fields med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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