[Studies on the injury effects of hippocampus induced by high power microwave radiation in rat].

Abstract

OBJECTIVE: To study the changes of morphology and function in rat hippocampus induced by high power microwave (HPM) radiation. METHODS: Fifty male Wistar rats were radiated by HPM. Then their learning and memory abilities were tested with Y maze and were sacrificed 6 h, 1 d, 3 d and 7 d after radiation. The hippocampus was taken out to study the basic pathologic changes, apoptosis and the expressions of neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) by means of HE staining, Nissel body staining, in situ terminal end labeling and immunohistochemistry. RESULTS: The learning and memory abilities of rats reduced significantly after HPM radiation. HPM also resulted in rarefaction, edema and hemangiectasia of hippocampus, nervous cells degeneration and necrosis, decrease or disappearance of Nissel bodies. The injuries were more serious in field CA4 and dentate gyrus, which showed dose-effect relationship, and were progressively aggravated within 7 days. The apoptosis cells were significantly increased. NSE was increased in neurons. The NSE positive areas were also seen in the interstitial matrix and blood vessels. GFAP was increased in astrocytes, which became shorter and thicker. CONCLUSION: HPM can damage the abilities of learning and memory and results in morphologic changes in hippocampus. The major pathologic changes are degeneration, apoptosis and necrosis of neurons and edema in interstitium. NSE and GFAP play an important role in the pathologic process.

AI evidence extraction

Main findings

After high power microwave radiation, rats showed significantly reduced learning and memory performance. Hippocampal injury findings included rarefaction, edema, hemangiectasia, neuronal degeneration/necrosis, and decreased/disappearing Nissl bodies; apoptosis increased and NSE and GFAP expression increased, with injuries described as more severe in CA4 and dentate gyrus and showing a dose-effect relationship.

Outcomes measured

• Learning and memory performance (Y maze)
• Hippocampal morphology/pathology (HE staining, Nissl staining)
• Apoptosis (in situ terminal end labeling)
• Neuron-specific enolase (NSE) expression
• Glial fibrillary acidic protein (GFAP) expression

Limitations

• Microwave exposure parameters (e.g., frequency, SAR, duration) not reported in the abstract
• No description of sham/control group in the abstract
• Dose levels and dosimetry details not provided in the abstract

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": "high power microwave radiation",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Male Wistar rats",
    "sample_size": 50,
    "outcomes": [
        "Learning and memory performance (Y maze)",
        "Hippocampal morphology/pathology (HE staining, Nissl staining)",
        "Apoptosis (in situ terminal end labeling)",
        "Neuron-specific enolase (NSE) expression",
        "Glial fibrillary acidic protein (GFAP) expression"
    ],
    "main_findings": "After high power microwave radiation, rats showed significantly reduced learning and memory performance. Hippocampal injury findings included rarefaction, edema, hemangiectasia, neuronal degeneration/necrosis, and decreased/disappearing Nissl bodies; apoptosis increased and NSE and GFAP expression increased, with injuries described as more severe in CA4 and dentate gyrus and showing a dose-effect relationship.",
    "effect_direction": "harm",
    "limitations": [
        "Microwave exposure parameters (e.g., frequency, SAR, duration) not reported in the abstract",
        "No description of sham/control group in the abstract",
        "Dose levels and dosimetry details not provided in the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "high power microwave",
        "microwave radiation",
        "rat",
        "hippocampus",
        "learning and memory",
        "Y maze",
        "apoptosis",
        "NSE",
        "GFAP",
        "histopathology"
    ],
    "suggested_hubs": []
}

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