50-Hz extremely low frequency electromagnetic fields enhance cell proliferation and DNA damage: possible involvement of a redox mechanism.

Biochimica et biophysica acta · 2005 · Harm · Low evidence

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HarmLow evidencePaper 5196

Study snapshot

PublicationBiochimica et biophysica acta · 2005

Study typein_vitro

Reported directionHarm

Evidence ratingLow

Abstract

HL-60 leukemia cells, Rat-1 fibroblasts and WI-38 diploid fibroblasts were exposed for 24-72 h to 0.5-1.0-mT 50-Hz extremely low frequency electromagnetic field (ELF-EMF). This treatment induced a dose-dependent increase in the proliferation rate of all cell types, namely about 30% increase of cell proliferation after 72-h exposure to 1.0 mT. This was accompanied by increased percentage of cells in the S-phase after 12- and 48-h exposure. The ability of ELF-EMF to induce DNA damage was also investigated by measuring DNA strand breaks. A dose-dependent increase in DNA damage was observed in all cell lines, with two peaks occurring at 24 and 72 h. A similar pattern of DNA damage was observed by measuring formation of 8-OHdG adducts. The effects of ELF-EMF on cell proliferation and DNA damage were prevented by pretreatment of cells with an antioxidant like alpha-tocopherol, suggesting that redox reactions were involved. Accordingly, Rat-1 fibroblasts that had been exposed to ELF-EMF for 3 or 24 h exhibited a significant increase in dichlorofluorescein-detectable reactive oxygen species, which was blunted by alpha-tocopherol pretreatment. Cells exposed to ELF-EMF and examined as early as 6 h after treatment initiation also exhibited modifications of NF kappa B-related proteins (p65-p50 and I kappa B alpha), which were suggestive of increased formation of p65-p50 or p65-p65 active forms, a process usually attributed to redox reactions. These results suggest that ELF-EMF influence proliferation and DNA damage in both normal and tumor cells through the action of free radical species. This information may be of value for appraising the pathophysiologic consequences of an exposure to ELF-EMF.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typein_vitro

Effect directionharm

PopulationCell lines: HL-60 leukemia cells; Rat-1 fibroblasts; WI-38 diploid fibroblasts

Sample sizeNot supplied

ExposureELF · 0.05 MHz · 24–72 h (also mentions 3, 6, 12, 24, 48, 72 h timepoints)

Evidence strengthLowConfidence: 86% · Peer reviewed: yes

Main findings

Exposure to 0.5–1.0 mT, 50-Hz ELF-EMF for 24–72 h induced a dose-dependent increase in proliferation (~30% increase after 72 h at 1.0 mT) and increased S-phase percentage. DNA damage increased dose-dependently (strand breaks and 8-OHdG), with peaks at 24 and 72 h; effects were prevented/blunted by alpha-tocopherol and accompanied by increased ROS and NF-κB-related protein changes suggestive of redox involvement.

Outcomes measured

Cell proliferation rate
Cell cycle distribution (S-phase percentage)
DNA strand breaks (DNA damage)
8-OHdG adduct formation
Reactive oxygen species (dichlorofluorescein-detectable)
NF-κB-related protein modifications (p65-p50, IκBα)
Effect modification by antioxidant (alpha-tocopherol)

Limitations

Sample size not reported in abstract
In vitro cell-line model; generalizability to humans not established in abstract
Exposure context/source outside laboratory setup not described

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": "24–72 h (also mentions 3, 6, 12, 24, 48, 72 h timepoints)"
  },
  "population": "Cell lines: HL-60 leukemia cells; Rat-1 fibroblasts; WI-38 diploid fibroblasts",
  "sample_size": null,
  "outcomes": [
    "Cell proliferation rate",
    "Cell cycle distribution (S-phase percentage)",
    "DNA strand breaks (DNA damage)",
    "8-OHdG adduct formation",
    "Reactive oxygen species (dichlorofluorescein-detectable)",
    "NF-κB-related protein modifications (p65-p50, IκBα)",
    "Effect modification by antioxidant (alpha-tocopherol)"
  ],
  "main_findings": "Exposure to 0.5–1.0 mT, 50-Hz ELF-EMF for 24–72 h induced a dose-dependent increase in proliferation (~30% increase after 72 h at 1.0 mT) and increased S-phase percentage. DNA damage increased dose-dependently (strand breaks and 8-OHdG), with peaks at 24 and 72 h; effects were prevented/blunted by alpha-tocopherol and accompanied by increased ROS and NF-κB-related protein changes suggestive of redox involvement.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not reported in abstract",
    "In vitro cell-line model; generalizability to humans not established in abstract",
    "Exposure context/source outside laboratory setup not described"
  ],
  "evidence_strength": "low",
  "confidence": 0.86,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF-EMF",
    "50 Hz",
    "0.5 mT",
    "1.0 mT",
    "cell proliferation",
    "DNA damage",
    "DNA strand breaks",
    "8-OHdG",
    "reactive oxygen species",
    "alpha-tocopherol",
    "NF-κB",
    "redox mechanism"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.bbamcr.2004.09.005
PubMed: 15777847

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