Effect of Different Methods of Mobile Phone Exposure on the Structure of Hippocampus in Adult Albino Rats

Abstract Introduction: Using mobile phones has dramatically increased in the last few years, especially during coronavirus pandemic. Mobile phones are carried near the head while talking. Electromagnetic fields (EMFs) emitted from cell phones may exert detrimental effects on the hippocampus. Aim: To study the effect of different methods of mobile phone exposure on the structure of the hippocampus in adult rats. Materials and Methods: Twenty-eight adult male albino Wistar rats were equally divided into four groups: group I (control). Group II (silent non-vibrating): exposed to 900–1800 MHz cell phone-emitted EMF for 60 min/day. Mobile phones were kept in silent, non-vibrating mode. Group III (silent vibrating): exposed to EMF as in group II, but mobile phones were kept in vibrating mode. Group IV (ringing non-vibrating): exposed to EMF as in group II, but with ringtone turned on and adjusted at 80 dB. After 4 weeks of exposure, hippocampi were harvested from all rats. They were subjected to hematoxylin and eosin, toluidine blue, caspase-3, and glial fibrillary acidic protein immunohistochemical stain, as well as transmission electron microscopic examination. Morphometric and statistical studies were also done. Results: Pyramidal and granule cells were affected by EMF exposure with predominant affection of CA3 area. Pyramidal cells in CA3 of group IV showed condensed chromatin clumps, distorted mitochondria, and clumped neurofilaments. A significant decrease in the thickness of the pyramidal cell layer and a significant increase in the mean number of degenerated pyramidal neurons were noticed in the CA3 area of group IV compared to other groups. An increased number of caspase-3 positive cells, as well as the increased number of astrocytes, were noticed in CA3 area of group IV compared to other groups. Conclusions: Exposure to EMF causes significant changes in the structure of the hippocampus, especially CA3 area. There is no significant difference between silent and vibrating modes. The worst changes are detected in ringing mode.