Compound exposure of 2.8 GHz and 9.3 GHz microwave causes learning and memory impairment in rats

Authors: Sun L, Wang X, Ren K, Yao C, Wang H, Xu X, Wang H, Dong J, Zhang J, Yao B, Wei X, Peng R, Zhao L

Year: 2025 Jan 3

Category: Neuroscience

Journal: Heliyon

DOI: 10.1016/j.heliyon.2025.e41626

URL: https://pmc.ncbi.nlm.nih.gov/articles/PMC11760294/

Abstract

Overview

Increasing public anxieties regarding the potential health hazards of microwave exposure have been noted recently. While earlier research has established that microwaves can cause structural and functional brain injuries, the specific effects of combined microwave frequencies remained largely unknown.

Study Details

  • Rats were sequentially exposed to 2.8 GHz and 9.3 GHz microwaves at an average power density of 10 mW/cm².
  • The biological impacts on the hippocampus were assessed through behavioral tests and physiological analyses.

Findings

  • Morris water maze navigation tests indicated a significant extension in average escape latency (AEL) at 1 and 3 days post-exposure, demonstrating impairment in learning and memory abilities.
  • Compound (combined) microwave exposures produced the most pronounced cognitive deficits at 3 days after exposure.
  • Electroencephalogram (EEG) analyses revealed increased power in certain brain wave frequencies, suggesting brain damage or dysfunction.
  • Histopathology showed clear structural injuries in the hippocampus at 7 days post-exposure, especially severe in the group exposed to both frequencies.
  • Mitochondrial disorder and decreased Nissl bodies were observed, potentially explaining decreased cognitive functions.
  • Encouragingly, cognitive function and hippocampal structure mostly recovered to normal after 28 days, likely due to self-recovery mechanisms.
  • Gene ontology (GO) and protein-protein interaction (PPI) analyses identified Htt and Bdnf as possible biomarkers for microwave-induced neuronal injury.

Conclusion

Sequential exposure to 2.8 GHz and 9.3 GHz microwaves causes identifiable, reversible structural injuries in the rat hippocampus, reducing cognitive function more than exposure to a single frequency alone. The damage involves mitochondrial disruption and decreased Nissl bodies, pointing to inhibited metabolism and neuronal function. Key genes (Htt, Htra, Psen1, Tp73, and Bdnf) may serve as indicators of this neurotoxicity. These findings reinforce the critical need to consider the cumulative effects of compound electromagnetic field exposures on brain health.

microwave exposure cognitive impairment hippocampus rats brain damage mitochondrial dysfunction learning and memory
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