Possible effects of RF EMR on contextual fear conditioning, hippocampal perivascular space, apoptosis and adrenal gland microarchitecture in rats

Abstract

Category: Neuroscience Tags: RF-EMR, hippocampus, adrenal gland, apoptosis, contextual fear conditioning, perivascular space, mobile phone radiation DOI: 10.1016/j.bbr.2025.115424 URL: sciencedirect.com Overview As mobile phone technology rapidly expands worldwide, concerns over the possible health effects induced by radiofrequency electromagnetic radiation (RF-EMR) have intensified. This study investigates the hypothesis that chronic 900 MHz RF-EMR exposure could dysregulate the stress response system (specifically the HPA axis) via non-thermal mechanisms. The study explores potential alterations in the microarchitecture of the adrenal gland and vulnerability in brain regions such as the hippocampus, which may lead to altered behaviors in rats. Methods - Male albino Wistar rats (aged four weeks, 50-60g) were exposed to 900 MHz radiation from a mobile phone for one hour daily over four weeks. - On day 29, control, sham exposed, and RF-EMR exposed rats underwent contextual fear conditioning tests. - After behavioral testing, rats were euthanized for examination of hippocampal and adrenal gland cytoarchitecture. Findings - RF-EMR exposed rats demonstrated significantly elevated transitions between bright and dark compartments in the avoidance box, and decreased latency to enter the dark compartment. - Marked apoptosis was observed in the CA3 region, and the perivascular space in the hippocampus was significantly enlarged in the exposed group. - The zona fasciculata of the adrenal gland displayed apoptotic-like changes, lymphocytic infiltrates, and congested sinusoids in the RF-EMR exposed group. - The cytoarchitecture of the adrenal medulla remained comparable across all groups. Conclusion Chronic exposure to RF-EMR at 900 MHz resulted in: - Changes in contextual fear conditioning behavior. - Enlargement of hippocampal perivascular space and induction of apoptosis in the CA3 region. - Apoptotic and inflammatory changes in the zona fasciculata of the adrenal gland. These findings indicate a clear association between chronic RF-EMR exposure and adverse neurobehavioral as well as histological changes, reinforcing the link between electromagnetic fields and health risks.

AI evidence extraction

Main findings

Rats exposed to 900 MHz RF-EMR from a mobile phone for 1 hour/day for 4 weeks showed altered avoidance behavior (increased transitions between compartments and decreased latency to enter the dark compartment). Histology showed marked apoptosis in hippocampal CA3 and significantly enlarged hippocampal perivascular space, along with apoptotic-like and inflammatory changes in the adrenal zona fasciculata; adrenal medulla cytoarchitecture was comparable across groups.

Outcomes measured

• Contextual fear conditioning behavior
• Avoidance box transitions between bright/dark compartments
• Latency to enter dark compartment
• Hippocampal CA3 apoptosis
• Hippocampal perivascular space size
• Adrenal gland microarchitecture (zona fasciculata, adrenal medulla)
• Adrenal zona fasciculata apoptotic-like changes
• Adrenal zona fasciculata lymphocytic infiltrates
• Adrenal zona fasciculata congested sinusoids

Limitations

• Sample size not reported in the abstract
• Specific exposure metrics (e.g., SAR, power density) not reported in the abstract
• Details of randomization/blinding not reported in the abstract

Suggested hubs

• mobile-phones (0.9)
  Exposure described as 900 MHz radiation from a mobile phone.

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        "band": "RF",
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        "frequency_mhz": 900,
        "sar_wkg": null,
        "duration": "1 hour daily for 4 weeks"
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    "population": "Male albino Wistar rats (aged four weeks, 50–60 g)",
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        "Latency to enter dark compartment",
        "Hippocampal CA3 apoptosis",
        "Hippocampal perivascular space size",
        "Adrenal gland microarchitecture (zona fasciculata, adrenal medulla)",
        "Adrenal zona fasciculata apoptotic-like changes",
        "Adrenal zona fasciculata lymphocytic infiltrates",
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    ],
    "main_findings": "Rats exposed to 900 MHz RF-EMR from a mobile phone for 1 hour/day for 4 weeks showed altered avoidance behavior (increased transitions between compartments and decreased latency to enter the dark compartment). Histology showed marked apoptosis in hippocampal CA3 and significantly enlarged hippocampal perivascular space, along with apoptotic-like and inflammatory changes in the adrenal zona fasciculata; adrenal medulla cytoarchitecture was comparable across groups.",
    "effect_direction": "harm",
    "limitations": [
        "Sample size not reported in the abstract",
        "Specific exposure metrics (e.g., SAR, power density) not reported in the abstract",
        "Details of randomization/blinding not reported in the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "RF-EMR",
        "radiofrequency electromagnetic radiation",
        "900 MHz",
        "mobile phone radiation",
        "hippocampus",
        "CA3",
        "apoptosis",
        "perivascular space",
        "contextual fear conditioning",
        "HPA axis",
        "adrenal gland",
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        "Wistar rats"
    ],
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