Comparing the Impact of Long-Term Exposure to Extremely Low-Frequency Electromagnetic Fields With Diverse Values on Anxiety, Memory, Learning, and Β-Amyloid Deposition in Adult Rats

Background: Extremely low-frequency electromagnetic fields (ELF-EMFs) have gathered significant consideration for their possible pathogenicity. However, their effects on nervous system functions were not fully clarified. In this study, our aim was to assay the effect of ELF-EMFs with different intensity on memory, anxiety, antioxidant activity, beta amyloid (Aβ) deposition and microglia population in rats. Materials and Methods: Fifty male adult rats were randomly separated into 5 groups; four groups exposed to a flux density of 1, 100, 500 and 2000 microtesla (µT), 50 Hertz (Hz) frequency for 1h/day for 2 months and one group as a control group. The control group were without ELF-EMF stimulation. After 8 weeks, passive avoidance and elevated plus maze (EPM) tests was performed to assess memory formation and anxiety-like behavior, respectively. Total free thiol groups and the index of lipid peroxidation were assessed. Also, for detection of β-Amyloid deposition and stained microglia in the brain, anti-β-amyloid and anti-Iba1 antibodies were used. Results: In the ELF-EMF exposure groups, the step-through latency was significantly greater in the retention test (100,500, and 2000 µT) than in the control group (P<0.05). Also, the percentage of the entries into the open arms in ELF-EMF exposure groups (especially 2000 µT) decreased than control group (P <0.05). No β-Amyloid depositions were detected in the hippocampus of different groups. An increase in microglia numbers in the 100, 500 and 2000 µT groups was observed in compare to the control and 1 µT group. Conclusion: Exposure to ELF-EMF had an anxiogenic effect on rats and promoted memory and also induced oxidative stress. No β-Amyloid depositions were detected in the brain. Also, positive effect of ELF-EMF was observed on population of microglia population in the brain.