Topic

Influence of mobile telecommunication fields on the permeability of the blood-brain barrier in laboratory rodents (in vivo)

Start

01.06.2004

End

31.05.2007

Project Management

University of Bordeaux (Laboratoire PIOM)

Objective

The task of this project was to determine the influence of high frequency electromagnetic fields used in mobile telecommunications systems (GSM and UMTS) on the permeability of the blood-brain barrier in vivo under conditions simulating a realistic exposure pattern as closely as possible. In particular, the following points should be clarified:

• Dependence of changes in permeability of the blood-brain barrier on specific absorption rates (SAR), duration of exposure and the post-exposure time.
• Investigating the question of whether delayed damage is introduced, whether any subsequent increase in permeability is reversible and if indications for remaining, possibly pathological processes can be detected.

Results

After a single 2 h exposure (GSM or UMTS) no consistent effect was found on induction of “dark neurons” or on BBB permeability, neither immediately nor up to 50 days after exposure (“Salford scenario”). Globally, the observed changes were limited and not predictive of deleterious effects, most of them were decreases in the parameters tested. Immediately after the last of the 4 weeks repeated exposure series neither induction of “dark neurons” nor on BBB permeability was observed, with the exception of one single significance (enhanced permeability for albumin at 0.26 W/kg, which did not show up 50 days after end of exposure). These results are in agreement with negative studies from Finnie et al. (2002,2006, Kuribayashi et al (2005), Cosquer et al. (2005), Kumlin et al. (2007) and Masuda et al. (2007).

The strongest and most consistent effect with regard to enhanced BBB permeability was observed 50 days after exposure to GSM-1800 at the highest SAR value (13 W/kg), in all brain zones. The amplitude of the effect was about a doubling in the number of leaking vessels (maximum 2.4 fold) corresponding to two leaking areas in exposed animals, as compared to one in sham-exposed animals. The amount of leaking vessels was still in the range of cage controls. Under none of the different conditions tested, a dose response was found.

The authors mention the possibility, that the effect at GSM 1800 (1/8 duty factor),13 W/kg could be linked to the occurrence of thermo-elastic waves that may act as a mechanical stress in the rat brain, inducing gradual BBB alteration.

An interim report including a literature survey and information about the exposure system is available as PDF file (846 KB) in English.

Interim Report (846 KB)

The final report including detailed information on methods and results can be downloaded as PDF File in English:

Final Report (2.808 KB)

Further information about the exposure system used in this study is published in Leveque et al. (2004) IEEE Transactions on Microwave Theory and Techniques, Vol. 52, No. 8.

Conclusions

The overall conclusion of the study is that physio-pathological consequences are unlikely to be expected in the rat brain after single and repeated exposure to GSM-1800 and UMTS, at BASAR levels up to 13 W/kg.