Medical/biological study (experimental study)

Neurobiological effects of repeated radiofrequency exposures in male senescent rats med./bio.

By: Bouji M, Lecomte A, Gamez C, Blazy K, Villegier AS

Published in: Biogerontology 2016; 17 (5-6): 841-857

Aim of study (acc. to author)

The effects of exposure of young and old rats to a 900 MHz electromagnetic field on memory and biochemical markers in the brain should be investigated to determine whether mobile phone exposure can exacerbate age-related neurobiological deficits.

Background/further details

Male young rats (4-5 months old) were divided into the following groups: 1) exposure to the electromagnetic field (n=7-8), 2) sham exposure (n=7-8), and 3) cage control (n=6). Male old rats (22-24 months old) were exposed under the same conditions and divided into the following groups: 4) exposure to the electromagnetic field (n=7-8), 5) sham exposure (n=7-8) and 6) cage control (n=6).
For the investigations of interleukin-1β and interleukin-6 levels in the brain, a positive control and a negative control was used for each group with 3 mice each.
After 26 days, rats were killed and biochemical parameters were analyzed.

Endpoint

effects on the neurological system: biochemical markers for age-related neurobiological deficits
cognitive/behavioral endpoints: memory and behavior

Exposure

- 900 MHz
- RF
- mobile communications
- mobile phone

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: continuous for 45 min on the experimental days 1–5, 8–12, 15–19 and 22–26	SAR: 6 W/kg spatial average (brain) power: 1 W (antenna output power)

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	continuous for 45 min on the experimental days 1–5, 8–12, 15–19 and 22–26

Modulation

Modulation type	pulsed
Duty cycle	12.5 %

Exposure setup

Exposure source	anechoic chamber loop antenna
Setup	radiofrequency generator was connected to 4 loop antennas allowing exposure of four animal heads simultaneously; animals were in restraint in individual plexiglass rockets (6 or 8.5 cm diameter, 15 or 21 cm in length, for young and old rats, respectively) capped with a truncated cone on which the loop antenna was fixed
Sham exposure	A sham exposure was conducted.
Additional info	exposed and sham exposed animals were placed in two identical anechoic chambers at the same time

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	6 W/kg	spatial average	measured and calculated	brain	-
power	1 W	-	-	-	antenna output power

Reference articles

Leveque P et al. (2004): Dosimetric Analysis of a 900-MHz Rat Head Exposure System
Dubreuil D et al. (2002): Does head-only exposure to GSM-900 electromagnetic fields affect the performance of rats in spatial learning tasks?

Exposed system:

animal
rat/Wistar
partial body: head

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: biochemical markers for age-related neurobiological deficits: levels of interleukin-1β and interleukin-6 levels in the brain and plasma corticosterone level (ELISA), GFAP protein expression in the cortex and hippocampus (immunohistochemistry, microscopy)
cognitive/behavioral endpoints: spatial learning and memory (accuracy, duration, reference memory errors and working memory errors, radial labyrinth), motor activity, exploration and anxiety behavior (open field test (elevated plus maze), emotional memory (freezing duration, fear conditioning with electric shocks and sound)

Investigated system:

isolated bio./chem. substance
tissue slices
brain homogenate, blood
investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

In old rats, significant deficits were observed in some parameters compared to young rats and a significant influence of immobilization (presumably due to stress) was found, but exposure to the electromagnetic field had no significant effect. Pooling old and young exposed rats (groups 1 and 4), a significantly reduced anxiety behavior was observed in rats exposed to a 900 MHz electromagnetic field compared to non-exposed rats.
The authors conclude that the present examinations on the effects of exposure of rats to a 900 MHz electromagnetic field on memory and biochemical markers in the brain provide no evidence that mobile phone exposure can exacerbate age-related neurobiological deficits.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Ministère de l'Ecologie, de l'Énergie, du Développement Durable et de la Mer (Ministry of Ecology, Energy, Sustainable Development, and Sea), France

Court-Kowalski S et al. (2015): Effect of long-term (2 years) exposure of mouse brains to global system for mobile communication (GSM) radiofrequency fields on astrocytic immunoreactivity
Klose M et al. (2014): Effects of Early-Onset Radiofrequency Electromagnetic Field Exposure (GSM 900 MHz) on Behavior and Memory in Rats
Saikhedkar N et al. (2014): Effects of mobile phone radiation (900 MHz radiofrequency) on structure and functions of rat brain
de Caires Jr LC et al. (2014): Behavior and memory evaluation of Wistar rats exposed to 1.8 GHz radiofrequency electromagnetic radiation
Hao D et al. (2013): Effects of long-term electromagnetic field exposure on spatial learning and memory in rats
Bouji M et al. (2012): Effects of 900 MHz radiofrequency on corticosterone, emotional memory and neuroinflammation in middle-aged rats
Ng TP et al. (2012): Long-term digital mobile phone use and cognitive decline in the elderly
Barth A et al. (2012): No effects of short-term exposure to mobile phone electromagnetic fields on human cognitive performance: A meta-analysis
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
Ntzouni MP et al. (2011): Short-term memory in mice is affected by mobile phone radiation
Ammari M et al. (2010): GFAP expression in the rat brain following sub-chronic exposure to a 900 MHz electromagnetic field signal
Finnie JW et al. (2010): Microglial activation as a measure of stress in mouse brains exposed acutely (60 minutes) and long-term (2 years) to mobile telephone radiofrequency fields
Fragopoulou AF et al. (2010): Whole body exposure with GSM 900MHz affects spatial memory in mice
Kumar RS et al. (2009): Hypoactivity of Wistar rats exposed to mobile phone on elevated plus maze
Daniels WM et al. (2009): The effect of electromagnetic radiation in the mobile phone range on the behaviour of the rat
Maaroufi K et al. (2009): Effects of prolonged iron overload and low frequency electromagnetic exposure on spatial learning and memory in the young rat
Narayanan SN et al. (2009): Spatial memory performance of Wistar rats exposed to mobile phone
Ammari M et al. (2008): Effect of head-only sub-chronic and chronic exposure to 900-MHz GSM electromagnetic fields on spatial memory in rats
Ammari M et al. (2008): Effect of a chronic GSM 900 MHz exposure on glia in the rat brain
Nittby H et al. (2008): Cognitive impairment in rats after long-term exposure to GSM-900 mobile phone radiation
Kumlin T et al. (2007): Mobile phone radiation and the developing brain: behavioral and morphological effects in juvenile rats
Brillaud E et al. (2007): Effect of an acute 900MHz GSM exposure on glia in the rat brain: a time-dependent study
Besset A et al. (2005): No effect on cognitive function from daily mobile phone use
Mausset-Bonnefont AL et al. (2004): Acute exposure to GSM 900-MHz electromagnetic fields induces glial reactivity and biochemical modifications in the rat brain
Dubreuil D et al. (2003): Head-only exposure to GSM 900-MHz electromagnetic fields does not alter rat's memory in spatial and non-spatial tasks
Dubreuil D et al. (2002): Does head-only exposure to GSM-900 electromagnetic fields affect the performance of rats in spatial learning tasks?