Effect of long‐term mobile communication microwave exposure on vascular permeability in mouse brain

Aims: To study the effect of long‐term exposure to global system for mobile communication (GSM) radiofrequency fields on vascular permeability in murine brains. Methods: Using a purpose‐designed exposure system at 900 MHz, mice were given a 60‐minute far‐field, whole body exposure on each of 5 days per week for 104 weeks at specific absorption rates (SAR) of 0.25, 1.0, 2.0 and 4.0 W/kg. Control mice were sham‐exposed or permitted free movement in a cage to evaluate any stress‐related effects. Albumin immunohistochemistry was used to detect increased vascular permeability and the efficacy of the vascular tracer was confirmed with a positive control group exposed to a clostridial toxin known to increase vascular permeability in the brain. Results: In all exposed and control groups, albumin extravasation was minimal, often leptomeningeal, and was deemed insignificant as a maximum of three capillaries or venules in a given brain showed leakage from the very many blood vessels present in the three coronal brain sections. Conclusions: These results suggest that prolonged exposure to mobile telephone‐type radiation produces negligible disruption to blood‐brain barrier integrity at the light microscope level using endogenous albumin as a vascular tracer.Abbreviations: BBB, blood-brain barrier; GSM, global system for mobile communication; RF, radiofrequency; SAR, specific absorption rate.