[Effects of NMDA receptor expression in rat's hippocampus after exposure to 1800 MHz radiofrequency field].

Abstract

OBJECTIVE: To identify the effects of NMDA receptor subunits NR2A and NR2B expression in rat's hippocampus after exposure to 1800 MHz radiofrequency radiation. METHODS: Four-week old female Wistar rats were randomly divided into four groups, with 12 animals for each. The subjects in two experimental groups had been continuously exposed to 1800 MHz microwave radiation (CW) with respective power density of 0.5 mW/cm(2) and 1.0 mW/cm(2) 12 hours each day for 21 days. Meanwhile, sham-controls were carried out. The brain tissue sections were performed by immunohistochemistry to demonstrate both expressions of NR2A, NR2B immune-activity in the hippocampal CA1, CA3 and DG by using computer-assisted image analysis system. RESULTS: In NR2A: the expression of 0.5 mW/cm(2) power density group was significantly lower than 0 mW/cm(2) power density group in CA3 [(8.5 +/- 1.5) vs (11.1 +/- 1.8), P < 0.01] and had not been significantly changed in CA1 and DG. The expression of 1.0 mW/cm(2) power density group was significantly lower than 0 mW/cm(2) power density group in CA1 and CA3 [(7.9 +/- 1.6) vs (9.7 +/- 1.5); (8.4 +/- 1.7) vs (11.1 +/- 1.8), respective P < 0.05, P < 0.01] and had not been significantly changed in DG. In NR2B: the expression of 0.5 mW/cm(2) power density group was significantly lower than 0 mW/cm(2) power density group in CA1 and CA3 [(16.4 +/- 1.0) vs (17.8 +/- 1.6); (9.6 +/- 1.9) vs (11.2 +/- 2.1), respective P < 0.05]. The expression of 1.0 mW/cm(2) power density group was significantly lower than 0 mW/cm(2) power density group in CA1, CA3 and DG [(13.1 +/- 2.4) vs (17.8 +/- 1.6); (9.3 +/- 1.4) vs (11.2 +/- 2.1); (7.3 +/- 0.1) vs (8.5 +/- 1.0), respective P < 0.01, P < 0.05, P < 0.05]. CONCLUSION: There were findings of the effects on NMDA receptor subunits in different hippocampus sections after exposure to 1800 MHz radiofrequency radiation.

AI evidence extraction

Main findings

Rats exposed to 1800 MHz CW RF at 0.5 or 1.0 mW/cm^2 for 12 h/day for 21 days showed significantly lower NR2A and/or NR2B immunoreactivity in specific hippocampal regions versus sham controls. Decreases were reported for NR2A in CA3 at 0.5 mW/cm^2 and in CA1 and CA3 at 1.0 mW/cm^2, with no significant change in DG; NR2B decreased in CA1 and CA3 at 0.5 mW/cm^2 and in CA1, CA3, and DG at 1.0 mW/cm^2.

Outcomes measured

• Hippocampal NMDA receptor subunit expression (NR2A, NR2B) by immunohistochemistry in CA1, CA3, DG

Limitations

• No SAR (W/kg) reported; exposure characterized by power density only
• Only female, young (4-week-old) rats studied
• Outcome limited to immunohistochemical expression measures; functional/behavioral correlates not reported in abstract
• Details on blinding, randomization procedures, and dosimetry not provided in abstract

{
    "study_type": "animal",
    "exposure": {
        "band": "RF",
        "source": null,
        "frequency_mhz": 1800,
        "sar_wkg": null,
        "duration": "12 hours/day for 21 days (continuous wave)"
    },
    "population": "Four-week-old female Wistar rats",
    "sample_size": 48,
    "outcomes": [
        "Hippocampal NMDA receptor subunit expression (NR2A, NR2B) by immunohistochemistry in CA1, CA3, DG"
    ],
    "main_findings": "Rats exposed to 1800 MHz CW RF at 0.5 or 1.0 mW/cm^2 for 12 h/day for 21 days showed significantly lower NR2A and/or NR2B immunoreactivity in specific hippocampal regions versus sham controls. Decreases were reported for NR2A in CA3 at 0.5 mW/cm^2 and in CA1 and CA3 at 1.0 mW/cm^2, with no significant change in DG; NR2B decreased in CA1 and CA3 at 0.5 mW/cm^2 and in CA1, CA3, and DG at 1.0 mW/cm^2.",
    "effect_direction": "harm",
    "limitations": [
        "No SAR (W/kg) reported; exposure characterized by power density only",
        "Only female, young (4-week-old) rats studied",
        "Outcome limited to immunohistochemical expression measures; functional/behavioral correlates not reported in abstract",
        "Details on blinding, randomization procedures, and dosimetry not provided in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "1800 MHz",
        "radiofrequency",
        "microwave radiation",
        "continuous wave",
        "power density",
        "rat",
        "hippocampus",
        "NMDA receptor",
        "NR2A",
        "NR2B",
        "immunohistochemistry",
        "CA1",
        "CA3",
        "dentate gyrus"
    ],
    "suggested_hubs": []
}

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