50 Hz Magnetic Field Exposure Inhibited Spontaneous Movement of Zebrafish Larvae through ROS-Mediated syn2a Expression.

Abstract

Extremely low frequency electromagnetic field (ELF-EMF) exists widely in public and occupational environments. However, its potential adverse effects and the underlying mechanism on nervous system, especially behavior are still poorly understood. In this study, zebrafish embryos (including a transfected synapsin IIa (syn2a) overexpression plasmid) at 3 h post-fertilization (hpf) were exposed to a 50-Hz magnetic field (MF) with a series of intensities (100, 200, 400 and 800 μT, respectively) for 1 h or 24 h every day for 5 days. Results showed that, although MF exposure did not affect the basic development parameters including hatching rate, mortality and malformation rate, yet MF at 200 μT could significantly induce spontaneous movement (SM) hypoactivity in zebrafish larvae. Histological examination presented morphological abnormalities of the brain such as condensed cell nucleus and cytoplasm, increased intercellular space. Moreover, exposure to MF at 200 μT inhibited syn2a transcription and expression, and increased reactive oxygen species (ROS) level as well. Overexpression of syn2a could effectively rescue MF-induced SM hypoactivity in zebrafish. Pretreatment with N-acetyl-L-cysteine (NAC) could not only recover syn2a protein expression which was weakened by MF exposure, but also abolish MF-induced SM hypoactivity. However, syn2a overexpression did not affect MF-increased ROS. Taken together, the findings suggested that exposure to a 50-Hz MF inhibited spontaneous movement of zebrafish larvae via ROS-mediated syn2a expression in a nonlinear manner.

AI evidence extraction

Main findings

Zebrafish embryos exposed to a 50-Hz magnetic field (100, 200, 400, 800 μT) for 1 h or 24 h daily for 5 days showed no changes in hatching rate, mortality, or malformation rate. Exposure at 200 μT was associated with reduced spontaneous movement (hypoactivity), brain morphological abnormalities, decreased syn2a transcription/expression, and increased ROS; syn2a overexpression rescued hypoactivity, and NAC pretreatment restored syn2a protein expression and abolished hypoactivity.

Outcomes measured

• Spontaneous movement (SM) activity in larvae
• Developmental parameters (hatching rate, mortality, malformation rate)
• Brain histology/morphology
• syn2a transcription and protein expression
• Reactive oxygen species (ROS) levels

Limitations

• Sample size not reported in abstract
• Exposure source/context (e.g., occupational/public device) not specified
• Only zebrafish model; generalizability to humans not addressed in abstract
• Nonlinear intensity effect noted (200 μT highlighted) but full dose-response details not provided

Suggested hubs

• occupational-exposure (0.3)
  Abstract notes ELF-EMF exists in public and occupational environments, though the experiment is an animal model without a specific occupational source.

{
    "study_type": "animal",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": 0.05000000000000000277555756156289135105907917022705078125,
        "sar_wkg": null,
        "duration": "1 h or 24 h every day for 5 days"
    },
    "population": "Zebrafish embryos/larvae (including synapsin IIa (syn2a) overexpression plasmid-transfected embryos)",
    "sample_size": null,
    "outcomes": [
        "Spontaneous movement (SM) activity in larvae",
        "Developmental parameters (hatching rate, mortality, malformation rate)",
        "Brain histology/morphology",
        "syn2a transcription and protein expression",
        "Reactive oxygen species (ROS) levels"
    ],
    "main_findings": "Zebrafish embryos exposed to a 50-Hz magnetic field (100, 200, 400, 800 μT) for 1 h or 24 h daily for 5 days showed no changes in hatching rate, mortality, or malformation rate. Exposure at 200 μT was associated with reduced spontaneous movement (hypoactivity), brain morphological abnormalities, decreased syn2a transcription/expression, and increased ROS; syn2a overexpression rescued hypoactivity, and NAC pretreatment restored syn2a protein expression and abolished hypoactivity.",
    "effect_direction": "harm",
    "limitations": [
        "Sample size not reported in abstract",
        "Exposure source/context (e.g., occupational/public device) not specified",
        "Only zebrafish model; generalizability to humans not addressed in abstract",
        "Nonlinear intensity effect noted (200 μT highlighted) but full dose-response details not provided"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "ELF-EMF",
        "50 Hz",
        "magnetic field",
        "zebrafish",
        "larvae",
        "spontaneous movement",
        "behavior",
        "ROS",
        "oxidative stress",
        "syn2a",
        "synapsin IIa",
        "N-acetyl-L-cysteine",
        "brain histology",
        "nonlinear dose-response"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.299999999999999988897769753748434595763683319091796875,
            "reason": "Abstract notes ELF-EMF exists in public and occupational environments, though the experiment is an animal model without a specific occupational source."
        }
    ]
}

Comments

Log in to comment.

No comments yet.