Effects of 1.5 and 4.3 GHz microwave radiation on cognitive function and hippocampal tissue structure in Wistar rats

Abstract

Effects of 1.5 and 4.3 GHz microwave radiation on cognitive function and hippocampal tissue structure in Wistar rats Ruiqing Zhu, Hui Wang, Xinping Xu, Li Zhao, Jing Zhang, Ji Dong, Binwei Yao, Haoyu Wang, Hongmei Zhou, Yabing Gao, Ruiyun Peng. Effects of 1.5 and 4.3 GHz microwave radiation on cognitive function and hippocampal tissue structure in Wistar rats Sci Rep. 2021 May 12;11(1):10061. doi: 10.1038/s41598-021-89348-4. Abstract Previous studies have shown that single-frequency microwave radiation can lead to cognitive decline in rats. However, few studies have focused on the combined effects of irradiation with different frequencies of microwaves. Our research aimed to investigate the effects of 1.5 GHz and 4.3 GHz microwave radiation, singly and in combination, on cognitive function and hippocampal tissue structure in rats. A total of 140 male Wistar rats were randomly divided into 4 groups: the S group (sham radiation group), L10 group (10 mW/cm2 1.5 GHz group), C10 group (10 mW/cm2 4.3 GHz band group) and LC10 group (10 mW/cm2 1.5 and 4.3 GHz multi- frequency radiation group). For 1-28 days after microwave radiation, we analyzed the average escape latency for the Morris water maze task, electroencephalograms, change in hippocampal tissue structure and ultrastructure, content of the Nissl body in the hippocampus, and activities of lactate dehydrogenase and succinate dehydrogenase. Compared to the S group, all exposure groups showed varying degrees of learning and memory decline and hippocampal structural damage. The results showed that 1.5 GHz and 4.3 GHz microwave radiation was able to induce cognitive impairment and hippocampal tissue damage in rats and combined radiation with both frequencies caused more serious injuries, but none of these damaging effects varied with microwave frequency. Excerpts The microwave pulses were delivered at 200 pps, with a pulse width of 500 ns. The peak field power densities tested with a calibrated detector and an oscilloscope for the exposure groups was 100 W/cm2. The average field power densities were calculated to be 10 mW/cm2 (Fig. 1A and Supplementary Fig. 1A).... [According to Table 1, the SAR values were 3.7 W/kg for the L10 group and 3.3 W/kg for the C10 group.] Open access paper: ncbi.nlm.nih.gov

AI evidence extraction

Main findings

Compared with sham, all exposed groups (1.5 GHz, 4.3 GHz, and combined 1.5+4.3 GHz at 10 mW/cm2) showed varying degrees of learning and memory decline and hippocampal structural damage. Combined multi-frequency exposure was reported to cause more serious injuries than single-frequency exposure, and the damaging effects were reported not to vary with microwave frequency.

Outcomes measured

• Cognitive function (Morris water maze escape latency; learning and memory)
• Electroencephalograms (EEG)
• Hippocampal tissue structure and ultrastructure
• Nissl body content in hippocampus
• Lactate dehydrogenase (LDH) activity
• Succinate dehydrogenase (SDH) activity

Limitations

• No details in abstract on blinding, allocation concealment, or handling of potential confounders
• Exposure duration and schedule (e.g., minutes/day) not specified in the provided abstract text
• Results are in rats; human relevance not directly established in the abstract

Suggested hubs

• 5g-policy (0.25)
  Includes 4.3 GHz RF/microwave exposure, which overlaps with higher-frequency cellular bands, though the study is animal and not explicitly 5G.

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "1–28 days after microwave radiation (follow-up/assessment window stated)"
    },
    "population": "Male Wistar rats",
    "sample_size": 140,
    "outcomes": [
        "Cognitive function (Morris water maze escape latency; learning and memory)",
        "Electroencephalograms (EEG)",
        "Hippocampal tissue structure and ultrastructure",
        "Nissl body content in hippocampus",
        "Lactate dehydrogenase (LDH) activity",
        "Succinate dehydrogenase (SDH) activity"
    ],
    "main_findings": "Compared with sham, all exposed groups (1.5 GHz, 4.3 GHz, and combined 1.5+4.3 GHz at 10 mW/cm2) showed varying degrees of learning and memory decline and hippocampal structural damage. Combined multi-frequency exposure was reported to cause more serious injuries than single-frequency exposure, and the damaging effects were reported not to vary with microwave frequency.",
    "effect_direction": "harm",
    "limitations": [
        "No details in abstract on blinding, allocation concealment, or handling of potential confounders",
        "Exposure duration and schedule (e.g., minutes/day) not specified in the provided abstract text",
        "Results are in rats; human relevance not directly established in the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "1.5 GHz",
        "4.3 GHz",
        "multi-frequency exposure",
        "Wistar rats",
        "cognition",
        "Morris water maze",
        "hippocampus",
        "ultrastructure",
        "EEG",
        "Nissl bodies",
        "LDH",
        "SDH",
        "SAR"
    ],
    "suggested_hubs": [
        {
            "slug": "5g-policy",
            "weight": 0.25,
            "reason": "Includes 4.3 GHz RF/microwave exposure, which overlaps with higher-frequency cellular bands, though the study is animal and not explicitly 5G."
        }
    ]
}

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