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

Heliyon · 2025 · Harm · Low evidence

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HarmLow evidencePaper 276

Study snapshot

PublicationHeliyon · 2025

Study typeanimal

Reported directionHarm

Evidence ratingLow

Abstract

Compound exposure of 2.8 GHz and 9.3 GHz microwave causes learning and memory impairment in rats 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. Compound exposure of 2.8 GHz and 9.3 GHz microwave causes learning and memory impairment in rats. Heliyon. 2025 Jan 3;11(1):e41626. doi: 10.1016/j.heliyon.2025.e41626. Abstract The anxieties and concerns about health hazards caused by microwave has been growing recently. Previous studies have reported microwave induced structural and functional injuries to brain. However, the biological effects caused by compound microwave were largely unexplored. In this study, we investigated the biological effects on rat's hippocampus after sequentially exposure to 2.8 GHz and 9.3 GHz at average power density of 10 mW/cm2 . Morris water maze (MWM) navigation tests showed that microwave exposure significantly extended the average escape latency (AEL) at 1d and 3d after exposure, suggesting reduced learning and memory ability. Importantly, compound microwave produced strongest responses at 3 d after exposure. Moreover, microwave also could induce abnormal electroencephalogram (EEG), such as increasing the power of θ wave and δ wave, suggesting brain damage or dysfunction. Histopathological analysis suggested that microwave resulted in obvious structural injuries in hippocampus at 7 d after exposure, and most serious injuries were observed in compound microwave exposed rats. Moreover, disorder of mitochondria and reduced Nissl bodies in hippocampus might contribute to the decrease of cognitive function. However, both the cognitive function and hippocampal structure restored to normal at 28 d after exposure, which might be attributed to self-recovery mechanisms. Gene ontology (GO) and Protein-protein interaction (PPI) analyses of differential expressed genes (DEGs) in peripheral blood suggested that Htt and Bdnf might be potential indicators to predict microwave. In conclusion, compound microwave of 2.8 GHz and 9.3 GHz could elicit reversible structural injuries to hippocampus, which could decrease the cognitive function of rats. Conclusion The composite microwave of 2.8 GHz and 9.3 GHz can cause damage to rat hippocampal tissue, inhibit brain activity, and reduce the metabolism of hippocampal neurons through inducing mitochondrial disorder and decreasing Nissl bodies, and ultimately impaired the learning and memory abilities of rats. Notably, compound microwave can reduce the learning and memory ability of rats more than single frequency microwave. Through a combination of GO and PPI analyses, we have also identified Htt, Htra, Psen1, Tp73, and Bdnf as potential predictive indicators of microwave-induced neuronal damage in the nervous system. Open access paper: pmc.ncbi.nlm.nih.gov

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal

Effect directionharm

PopulationRats

Sample sizeNot supplied

Exposuremicrowave

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Rats sequentially exposed to 2.8 GHz and 9.3 GHz microwaves at an average power density of 10 mW/cm2 showed significantly increased escape latency in the Morris water maze at 1 and 3 days post-exposure, with the strongest effects at 3 days. EEG abnormalities (increased theta and delta power) and hippocampal structural injuries (most severe in compound-exposed rats) were observed, with reported recovery of cognitive function and hippocampal structure by 28 days post-exposure; GO/PPI analyses suggested several genes (including Htt and Bdnf) as potential indicators.

Outcomes measured

Learning and memory performance (Morris water maze; escape latency)
Electroencephalogram (EEG) changes (theta and delta power)
Hippocampal histopathology/structural injury
Mitochondrial disorder (hippocampus)
Nissl bodies (hippocampus)
Differentially expressed genes (peripheral blood); GO/PPI analyses; candidate indicators (e.g., Htt, Bdnf)

Limitations

Sample size not reported in abstract
Exposure duration and detailed exposure protocol parameters not reported in abstract (beyond sequential exposure and average power density)
No SAR reported in abstract
Findings are from an animal model; human relevance not established in abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "microwave",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Rats",
  "sample_size": null,
  "outcomes": [
    "Learning and memory performance (Morris water maze; escape latency)",
    "Electroencephalogram (EEG) changes (theta and delta power)",
    "Hippocampal histopathology/structural injury",
    "Mitochondrial disorder (hippocampus)",
    "Nissl bodies (hippocampus)",
    "Differentially expressed genes (peripheral blood); GO/PPI analyses; candidate indicators (e.g., Htt, Bdnf)"
  ],
  "main_findings": "Rats sequentially exposed to 2.8 GHz and 9.3 GHz microwaves at an average power density of 10 mW/cm2 showed significantly increased escape latency in the Morris water maze at 1 and 3 days post-exposure, with the strongest effects at 3 days. EEG abnormalities (increased theta and delta power) and hippocampal structural injuries (most severe in compound-exposed rats) were observed, with reported recovery of cognitive function and hippocampal structure by 28 days post-exposure; GO/PPI analyses suggested several genes (including Htt and Bdnf) as potential indicators.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not reported in abstract",
    "Exposure duration and detailed exposure protocol parameters not reported in abstract (beyond sequential exposure and average power density)",
    "No SAR reported in abstract",
    "Findings are from an animal model; human relevance not established in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "microwave",
    "2.8 GHz",
    "9.3 GHz",
    "compound exposure",
    "sequential exposure",
    "rats",
    "hippocampus",
    "learning and memory",
    "Morris water maze",
    "EEG",
    "mitochondria",
    "Nissl bodies",
    "gene ontology",
    "protein-protein interaction",
    "Htt",
    "Bdnf"
  ],
  "suggested_hubs": [
    {
      "slug": "animal-studies",
      "weight": 0.9,
      "reason": "Experimental microwave exposure study in rats assessing neurobehavioral and hippocampal outcomes."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.heliyon.2025.e41626
PubMed: Not supplied

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