McQuade, J. M.; Merritt, J. H.; Miller, S. A.; Scholin, T.; Cook, M. C.; Salazar, A.; Rahimi, O. B.; Murphy, M. R., and Mason, P. A. Radiofrequency-radiation exposure does not induce detectable leakage of albumin across the blood-brain barrier. Radiat Res. 2009 May; 171(5):615-21.
The blood-brain barrier (BBB) is vital for maintaining the environment of the central nervous system (CNS). Increased permeability of the BBB can lead to neurological damage. There is no agreement in the literature as to whether or not exposure to low-power RF radiation causes alterations in the integrity of the BBB. Such alterations were reported in a Swedish study after exposure to low-power 915 MHz energy.
This was a confirmation study of the Swedish experiments. The primary objective was to conduct an experiment including the range of exposure parameters used in the Swedish study, but adjusted to exclude possible confounding factors, such as sex, age, size of animals, and placement within the exposure system.
Male rats of the Fisher 344 CD-VAF strain were exposed to 915 MHz radiation or sham-exposed for 30 minutes. In addition to sham-exposed animals, home cage controls, which were not removed from their housing facility, were used in this study. Both continuous-wave (CW) and pulsed modes of 16 and 217 Hz were used. SAR levels for CW group were 0.002, 0.02, 0.2, 2 and 20 W/kg, for 16 HZ-modulated – 0.0018, 0.018, and 0.18, for 217 Hz modulated – 0.0025, 0.025, 0.248 and 2.48 W/kg. The albumin immunohistochemistry staining was performed on brain tissue sections to evaluate the integrity of the BBB.
Little or no intracellular or extracellular extravasation was observed in all the groups, and there were no significant differences between the EMF-exposed, sham-exposed or home-caged rats.
Interpretation and conclusion
This study failed to confirm the results of the Swedish study. The authors conclude that their study provides no evidence of alterations in the permeability of the BBB after exposure to RF radiation within the permissible levels set by ICNIRP and IEEE.