[A aquaporin 4 expression and effects in rat hippocampus after microwave radiation].

Abstract

OBJECTIVE: To investigate the expression of aquaporin 4 (AQP4) after microwave exposure and the correlation with the brain injury by radiation. METHODS: 70 male rats were exposed to microwave whose average power density was 0, 10, 30 and 100 mW/cm(2) respectively. Rats were sacrificed at 6 h, 1 d, 3 d and 7 d after exposure. Immunohistochemistry and Western blot were used to detect the expression of AQP4 in protein level in rat hippocampus, and the expression of AQP4 in gene level was measured by in situ hybridization and RT-PCR. RESULTS: The expression of AQP4 in rat hippocampus was abnormal after 10, 30, 100 mW/cm(2) microwave exposure. The protein level showed increased at first and then recovered at 10 and 30 mW/cm(2) groups, while increased progressively in 100 mW/cm(2) group within 14 d (P < 0.01). The gene expression of AQP4 was increased (0.51 +/- 0.02) at the beginning (6 h) and then regained after 10 mW/cm(2) microwave exposure, while in 30 and 100 mW/cm(2) groups, it rose to the peak at 7 d (0.46 +/- 0.02 and 0.43 +/- 0.08) and didn't get back (P = 0.004; P = 0.012). CONCLUSION: Microwave radiation can increase the expression of AQP4 in rat hippocampus. The change might participate in the process of increasing permeability of blood-brain barrier and lead to the brain edema after microwave radiation.

AI evidence extraction

Main findings

After microwave exposure at 10, 30, and 100 mW/cm^2, AQP4 expression in rat hippocampus was reported as abnormal. Protein expression increased initially then recovered in the 10 and 30 mW/cm^2 groups, while it increased progressively in the 100 mW/cm^2 group within 14 days (P<0.01). Gene expression increased early (6 h) then recovered in the 10 mW/cm^2 group, but in the 30 and 100 mW/cm^2 groups it peaked at 7 days and did not return to baseline (P=0.004; P=0.012).

Outcomes measured

• Aquaporin 4 (AQP4) protein expression in rat hippocampus
• AQP4 gene/mRNA expression in rat hippocampus

Limitations

• Microwave frequency not reported
• Exposure duration per session not reported
• Outcomes are biomarker/expression measures; direct measures of blood-brain barrier permeability or edema are not reported in the abstract
• Animal study; generalizability to humans is uncertain

Suggested hubs

• animal-studies (0.9)
  Experimental microwave exposure study in rats assessing brain molecular changes.

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Male rats",
    "sample_size": 70,
    "outcomes": [
        "Aquaporin 4 (AQP4) protein expression in rat hippocampus",
        "AQP4 gene/mRNA expression in rat hippocampus"
    ],
    "main_findings": "After microwave exposure at 10, 30, and 100 mW/cm^2, AQP4 expression in rat hippocampus was reported as abnormal. Protein expression increased initially then recovered in the 10 and 30 mW/cm^2 groups, while it increased progressively in the 100 mW/cm^2 group within 14 days (P<0.01). Gene expression increased early (6 h) then recovered in the 10 mW/cm^2 group, but in the 30 and 100 mW/cm^2 groups it peaked at 7 days and did not return to baseline (P=0.004; P=0.012).",
    "effect_direction": "harm",
    "limitations": [
        "Microwave frequency not reported",
        "Exposure duration per session not reported",
        "Outcomes are biomarker/expression measures; direct measures of blood-brain barrier permeability or edema are not reported in the abstract",
        "Animal study; generalizability to humans is uncertain"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "aquaporin 4",
        "AQP4",
        "hippocampus",
        "rat",
        "blood-brain barrier",
        "brain edema",
        "immunohistochemistry",
        "Western blot",
        "RT-PCR",
        "in situ hybridization"
    ],
    "suggested_hubs": [
        {
            "slug": "animal-studies",
            "weight": 0.90000000000000002220446049250313080847263336181640625,
            "reason": "Experimental microwave exposure study in rats assessing brain molecular changes."
        }
    ]
}

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