Effect of 835aaMHz radiofrequency radiation exposure on calcium binding proteins in the hippocampus of the mouse brain

Worldwide expansion of mobile phones and electromagnetic field (EMF) exposure has raised question of their possible biological effects on the brain and nervous system. Radiofrequency (RF) radiation might alter intracellular signaling pathways through changes in calcium (Ca2+) permeability across cell membranes. Changes in the expression of calcium binding proteins (CaBP) like calbindin D28-k (CB) and calretinin (CR) could indicate impaired Ca2+homeostasis due to EMF exposure. CB and CR expression were measured with immunohistochemistry in the hippocampus of mice after EMF exposure at 835aaMHz for different exposure times and absorption rates, 1aah/day for 5aadays at a specific absorption rate (SAR)=1.6aaW/kg, 1aah/day for 5aadays at SAR=4.0aaW/kg, 5aah/day for 1aaday at SAR=1.6aaW/kg, 5aah/day for 1aaday at SAR=4.0aaW/kg, daily exposure for 1aamonth at SAR=1.6aaW/kg. Body weights did not change significantly. CB immunoreactivity (IR) displayed moderate staining of cells in the cornu ammonis (CA) areas and prominently stained granule cells. CR IR revealed prominently stained pyramidal cells with dendrites running perpendicularly in the CA area. Exposure for 1aamonth produced almost complete loss of pyramidal cells in the CA1 area. CaBP differences could cause changes in cellular Ca2+levels, which could have deleterious effect on normal hippocampal functions concerned with neuronal connectivity and integration.