Medical/biological study (experimental study, review/survey)

Increased blood-brain barrier permeability in mammalian brain 7 days after exposure to the radiation from a GSM-900 mobile phone. med./bio.

By: Nittby H, Brun A, Eberhardt J, Malmgren L, Persson BR, Salford LG

Published in: Pathophysiology 2009; 16 (2-3): 103-112

Aim of study (acc. to author)

To study the effects of GSM mobile phone irradiation upon the blood-brain barrier permeability of rats seven days after one occasion of 2 h of exposure and whether the same increase of the blood-brain barrier permeability is seen seven days after exposure as that showed immediately after exposure (see Persson et al. 1997) and after 14 days (see Eberhardt et al. 2008), and whether different exposure levels (SAR values) result in a different responses.
The first section of the article inculdes also a review of the literature on the effects (or lack of effects) of microwave exposure upon the blood-brain barrier.

Background/further details

48 rats were exposed at non-thermal specific absorption rates of 0 mW/kg (n=16), 0.12 mW/kg (n=8), 1.2 mW/kg (n=8), 12 mW/kg (n=8) and 120 mW/kg (n=8).

Endpoint

effects on the neurological system: blood-brain barrier permeability and neuronal damage

Exposure

- microwaves
- mobile communications
- mobile phone
- GSM

Exposure	Parameters
Exposure 1: 915 MHz Modulation type: pulsed Exposure duration: continuous for 2 hr	power: 1 mW peak value power: 10 mW peak value power: 100 mW peak value power: 1,000 mW peak value SAR: 0.12 mW/kg average over mass (whole body) SAR: 1.2 mW/kg average over mass (whole body) SAR: 12 mW/kg average over mass (whole body) SAR: 120 mW/kg average over mass (whole body)

Exposure 1

Main characteristics

Frequency	915 MHz
Type	electromagnetic field
Exposure duration	continuous for 2 hr

Modulation

Modulation type	pulsed

Exposure setup

Exposure source	cellular phone TEM cell
Setup	GSM mobile phone connected via a coaxial cable to the TEM cell; TEM cell cenclosed in a 15 cm x 15 cm x 15 cm wooden box that supports the outer brass net conductor and the central conducting plate; rats placed in 14 cm x 14 cm x 7 cm plastic tray in the TEM cell
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	1 mW	peak value	-	-	-
power	10 mW	peak value	-	-	-
power	100 mW	peak value	-	-	-
power	1,000 mW	peak value	-	-	-
SAR	0.12 mW/kg	average over mass	-	whole body	-
SAR	1.2 mW/kg	average over mass	-	whole body	-
SAR	12 mW/kg	average over mass	-	whole body	-
SAR	120 mW/kg	average over mass	-	whole body	-

Additional parameter details

the average SAR for the brain gray matter was 1.06 times that of the average whole body SAR

Reference articles

Eberhardt JL et al. (2008): Blood-brain barrier permeability and nerve cell damage in rat brain 14 and 28 days after exposure to microwaves from GSM mobile phones.
Salford LG et al. (2008): The mammalian brain in the electromagnetic fields designed by man with special reference to blood-brain barrier function, neuronal damage and possible physical mechanisms.
Nittby H et al. (2008): Cognitive impairment in rats after long-term exposure to GSM-900 mobile phone radiation.
Salford LG et al. (2007): Non-thermal effects of EMF upon the mammalian brain: the Lund experience.
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.
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

effects on the neurological system: blood-brain barrier permeability (diffuse occurence and foci of albumin, albumin uptake into neurons: microscopy, immunostaining for albumin) and nerve cell damage (occurence of damaged "dark" neurons: cresyl violet staining)

Investigated system:

tissue slices

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Albumin extravasation was statistically significant increased in the mobile phone exposed rats as compared to sham exposed controls after this 7-day recovery period at the SAR value of 12 mW/kg and with a trend of enhanced albumin extravasation also at the SAR values of 0.12 mW/kg and 120 mW/kg. There was a low, but significant correlation between the exposure level (SAR-value) and occurrence of focal albumin extravasation.
The data are in agreement with earlier studies of the authors (see above and "related articles") where they have seen increased permeability of blood-brain barrier immediately and 14 days after exposure.

Study character:

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

Study funded by

Märit and Hans Rausing Charitable Foundation, UK

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Salford LG et al. (2008): The mammalian brain in the electromagnetic fields designed by man with special reference to blood-brain barrier function, neuronal damage and possible physical mechanisms.
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