The effect of 900-megahertz electromagnetic field on hippocampus morphology and learning behavior in adolescent male rats

The aim of this study was to investigate hippocampus morphology and changes in learning behavior in adolescent male rats exposed to the effect of a 900-megahertz electromagnetic field (EMF). Twenty-four male Sprague Dawley rats aged 3-weeks were divided equally into control, sham and EMF groups. EMF group rats were exposed to a 900-megahertz EMF in an EMF cage, while the sham group rats were placed in the same cage but exposed to no effect. No procedure was performed in the control group. Following 25-day application of EMF, passive avoidance, the 8-arm radial maze and Y-maze tests were performed to determine rats' learning and memory performances. Open field and rotarod tests were performed to assess locomotor activity. At the end of the tests, the animals were sacrificed and their brains removed. Following histological tissue procedures, sections were taken from tissues and stained with toluidine blue. The optical dissector technique, a stereological method, was used to investigate pyramidal cell numbers in the CA1, CA2, CA3 and hilus regions of the hippocampus and granular cell numbers in the dentate gyrus region. Histopathological evaluation was performed in the same areas. The tissue oxidative stress parameters malondialdehyde, superoxide dismutase, glutathione and catalase values were investigated at biochemical examination. At histopathological examination, vacuolization and impairment of pyramidal and granular cell structures were observed in the EMF group hippocampus. Stereological analysis revealed a significant increase in EMF group granular and pyramidal cell numbers. A significant increase in EMF group superoxide dismutase activity was observed at biochemical analyses. No significant change was observed in learning, memory or locomotor behavior in any group. In conclusion, 900-megahertz EMF applied in adolescence causes an increase in neurons, changes in morphological structure in the male rat hippocampus, but no changes in learning, memory or locomotor behavior.