Effects of exposure to ELF-EMF on spatial & passive avoidance learning & memory, anxiety-like behavior & oxidative stress in male rats

Abstract

Effects of exposure to ELF-EMF on spatial & passive avoidance learning & memory, anxiety-like behavior & oxidative stress in male rats Asaad Karimi S, Salehi I, Shykhi T, Zare S, Komaki A. Effects of exposure to extremely low-frequency electromagnetic fields on spatial and passive avoidance learning and memory, anxiety-like behavior and oxidative stress in male rats. Behav Brain Res. 2018 Oct 2. pii: S0166-4328(18)31074-X. doi: 10.1016/j.bbr.2018.10.002. Abstract There are many controversies about the safety of extremely low-frequency electromagnetic field (ELF-EMF) on body health and cognitive performance. In the present study, we explored the effects of ELF-EMF on oxidative stress and behaviors of rats. Seventy-two adult male Wistar rats were randomly divided into following groups, control, sham exposure group and the ELF-EMF exposure groups (1 µT, 100 µT, 500 µT, and 2000 µT). After 60 days exposure (2 h/day), elevated plus maze (EPM), Morris water maze (MWM) and Passive avoidance learning (PAL) tasks were used to evaluate the anxiety-like behavior, spatial and passive learning and memory, respectively. Some days after behavioral examination, oxidative stress markers were measured. During spatial reference memory test, animals in ELF-EMF exposure groups (100, and 2000 µT) spent more time in target zone (F (4, 55) = 5.699, P = 0.0007, One-way ANOVA). In PAL retention, the step through latency in the retention test (STLr) in ELF-EMF exposure groups (100,500, and 2000 µT) was significantly greater than control group (F (4, 55) = 29.13, P < 0.0001, One-way ANOVA). In EPM test, ELF-EMF exposure (500 and 2000 µT) decreased the percentage of the entries into the open arms (F (4, 55) = 26.31, P < 0.0001, one-way ANOVA). ELF-EMF exposure (100, and 500 µT) increased Malondialdehyde (MDA) concentration (F (4, 25) = 79.83, P < 0.0001, One-way ANOVA). Our results may allow the conclusion that exposure to ELF-EMFs can improve memory retention (but not acquisition) in the adult male rats. Although exposure to ELF-EMFs could be a factor in the development of anxious state or oxidative stress. ncbi.nlm.nih.gov

AI evidence extraction

Main findings

In spatial reference memory testing, rats exposed to 100 and 2000 µT spent more time in the target zone than controls. In passive avoidance retention, step-through latency was higher in the 100, 500, and 2000 µT groups versus control. In the elevated plus maze, 500 and 2000 µT decreased the percentage of open-arm entries, and MDA concentration increased in the 100 and 500 µT groups.

Outcomes measured

• Spatial learning and memory (Morris water maze; time in target zone)
• Passive avoidance learning and memory (step-through latency in retention test)
• Anxiety-like behavior (elevated plus maze; % open-arm entries)
• Oxidative stress markers (malondialdehyde, MDA)

Limitations

• Frequency of the ELF-EMF exposure not reported in abstract
• Exposure source/setup not described in abstract
• Only adult male rats studied (generalizability limits)
• Some outcomes show effects only at certain intensities (non-monotonic pattern)

{
    "study_type": "animal",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "60 days (2 h/day); field intensities 1, 100, 500, 2000 µT"
    },
    "population": "Adult male Wistar rats",
    "sample_size": 72,
    "outcomes": [
        "Spatial learning and memory (Morris water maze; time in target zone)",
        "Passive avoidance learning and memory (step-through latency in retention test)",
        "Anxiety-like behavior (elevated plus maze; % open-arm entries)",
        "Oxidative stress markers (malondialdehyde, MDA)"
    ],
    "main_findings": "In spatial reference memory testing, rats exposed to 100 and 2000 µT spent more time in the target zone than controls. In passive avoidance retention, step-through latency was higher in the 100, 500, and 2000 µT groups versus control. In the elevated plus maze, 500 and 2000 µT decreased the percentage of open-arm entries, and MDA concentration increased in the 100 and 500 µT groups.",
    "effect_direction": "mixed",
    "limitations": [
        "Frequency of the ELF-EMF exposure not reported in abstract",
        "Exposure source/setup not described in abstract",
        "Only adult male rats studied (generalizability limits)",
        "Some outcomes show effects only at certain intensities (non-monotonic pattern)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "ELF-EMF",
        "extremely low-frequency",
        "rats",
        "Wistar",
        "Morris water maze",
        "passive avoidance",
        "elevated plus maze",
        "anxiety-like behavior",
        "oxidative stress",
        "malondialdehyde",
        "MDA"
    ],
    "suggested_hubs": []
}

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