Medical/biological study (experimental study)

Cognitive impairment in rats after long-term exposure to GSM-900 mobile phone radiation med./bio.

By: Nittby H, Grafstrom G, Tian DP, Malmgren L, Brun A, Persson BR, Salford LG, Eberhardt J

Published in: Bioelectromagnetics 2008; 29 (3): 219-232

Aim of study (acc. to author)

To evaluate whether long-term exposure to GSM mobile phones might give rise to changes in cognitive functions, the authors exposed male and female rats to GSM mobile phone electromagnetic fields for 2 h once a week for a total of 55 weeks.

Background/further details

Out of a total of 56 rats, 32 rats were exposed (two groups at different SAR values), 16 animals were sham exposed and 8 animals were cage controls.
Behavioural tests were performed during a period from 3 to 7 weeks after the last exposure or sham exposure.

Endpoint

cognitive/behavioral endpoints: exploratory behavior and memory function

Exposure

- mobile communications
- digital mobile phone
- GSM

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: 2 h/week for 55 weeks	SAR: 0.6 mW/kg average over mass (whole body) (at 33 mW/m²) SAR: 60 mW/kg average over mass (whole body) (at 3.3 W/m²) power density: 33 mW/m² power density: 3.3 W/m²

General information

animals were treated in three groups: i) exposure to GSM ii) sham exposure iii) cage control

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	2 h/week for 55 weeks

Modulation

Modulation type	pulsed

Exposure setup

Exposure source	cellular phone TEM cell
Setup	GSM test phone connected to four TEM cells, rats placed on plastic trays in the TEM cells
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.6 mW/kg	average over mass	calculated	whole body	at 33 mW/m²
SAR	60 mW/kg	average over mass	calculated	whole body	at 3.3 W/m²
power density	33 mW/m²	-	-	-	-
power density	3.3 W/m²	-	-	-	-

Reference articles

Crawford ML (2016): Generation of standard EM fields using TEM transmission cells
Belyaev IY et al. (2006): Exposure of rat brain to 915 MHz GSM microwaves induces changes in gene expression but not double stranded DNA breaks or effects on chromatin conformation
Salford LG et al. (2003): Nerve cell damage in mammalian brain after exposure to microwaves from GSM mobile phones
Persson BRR et al. (1997): Blood-brain barrier permeability in rats exposed to electromagnetic fields used in wireless communication
Salford LG et al. (1994): Permeability of the blood-brain barrier induced by 915 MHz electromagnetic radiation, continuous wave and modulated at 8, 16, 50, and 200 Hz
Salford LG et al. (1993): Permeability of the blood-brain barrier induced by 915 MHz electromagnetic radiation, continuous wave and modulated at 8, 16, 50 and 200 Hz

Exposed system:

animal
rat/Fischer 344
whole body

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: exploratory behavior (number of crossings, rearings, defecations, urinations; open field test) and memory (exploration time, long-term memory for different objects, their spatial location and order of presentation; episodic-like memory test)
body weight

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

The exposed rats (both groups) showed a significant impairment in episodic-like memory when compared to that of sham exposed animals. Exposed rats had impaired memory for objects and their temporal order of presentation compared to sham exposed rats. The observed impairment following exposure cannot be attributed to acute stress, because tests were performed during a period of 3-7 weeks after the last exposure.
In the open field test no difference was found.
The data suggest significantly reduced memory functions in rats after GSM microwave exposure.

Study character:

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

Study funded by

Märit and Hans Rausing Charitable Foundation, UK
Swedish Council for Working Life and Social Research (FAS)

Comments on this article

Nordström CH (2009): Comments on "cognitive impairment in rats after long-term exposure to GSM-900 mobile phone radiation" by Nittby et al. (Bioelectromagnetics 29:219-232, 2008)
Nittby H et al. (2009): Response to comments on cognitive impairment in rats after long-term exposure to GSM-900 mobile phone radiation by Nittby et al. (Bioelectromagnetics 29:219-232, 2008)

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