Non-thermal effects of power-line magnetic fields (50 Hz) on gene expression levels of pluripotent embryonic stem cells-the role of tumour suppressor p53.

Mutation research · 2004 · Mixed · Low evidence

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MixedLow evidencePaper 5240

Intermittent 50 Hz power-line magnetic field exposure (5 min ON/30 min OFF) at 2.3 mT for 6 h significantly up-regulated c-jun, p21, and egr-1 mRNA levels in p53-deficient ES cells but not in wild-type ES cells. No significant effects were observed at lower f…

Study snapshot

PublicationMutation research · 2004

Study typein_vitro

Reported directionMixed

Evidence ratingLow

Abstract

The diffusion of extremely low-frequency (50 Hz) electromagnetic fields (ELF-EMF) in the human environment raises the question of the induction of biological effects of EMF on mammalian cells. We used the model of mouse pluripotent embryonic stem (ES) cells, which have the capacity to develop in vitro into cells of all lineages, to analyse non-thermal effects of ELF-EMF. Wild type (wt) and p53-deficient ES cells were exposed under controlled conditions to ELF-EMF signals simulating power-line (50 Hz) magnetic field (PL-MF) exposure. Different flux densities of 0.1 mT, 1.0 mT or 2.3 mT and intermittency schemes with various ON/OFF cycles were applied for 6 h or 48 h during the first stages of cell differentiation. Transcript levels of regulatory genes, such as egr-1, p21, c-jun, c-myc, hsp70 and bcl-2, were analysed by semi-quantitative RT-PCR immediately after exposure or after a recovery time of 18 h. Intermittent PL-MF exposure to 5 min ON/30 min OFF cycles at a flux density of 2.3 mT for 6 h resulted in a significant up-regulation of c-jun, p21 and egr-1 mRNA levels in p53-deficient, but not in wild-type cells. No significant effects were observed in both cell systems by PL-MF at lower flux densities, longer exposure time or after 18 h recovery time. Our data indicate that 5 min ON/30 min OFF intermittent PL-MF exposure is capable of evoking non-thermal responses in ES cells, dependent on the cellular p53 function. The nature of the biological responses triggered by PL-MF is discussed.

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AI evidence extraction

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Study typein_vitro

Effect directionmixed

PopulationMouse pluripotent embryonic stem (ES) cells (wild type and p53-deficient)

Sample sizeNot supplied

ExposureELF · 6 h or 48 h (with some outcomes assessed immediately after exposure or after 18 h recovery)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Outcomes measured

mRNA/transcript levels of regulatory genes (egr-1, p21, c-jun, c-myc, hsp70, bcl-2) measured by semi-quantitative RT-PCR
Gene expression changes during early stages of ES cell differentiation

Limitations

In vitro model (mouse ES cells) may not generalize to in vivo or human outcomes
Sample size not reported in abstract
Gene expression assessed by semi-quantitative RT-PCR (methodological detail limited in abstract)
Effects depended on p53 status and specific intermittency/flux density conditions; other exposure conditions showed no significant effects

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": "power line",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "6 h or 48 h (with some outcomes assessed immediately after exposure or after 18 h recovery)"
  },
  "population": "Mouse pluripotent embryonic stem (ES) cells (wild type and p53-deficient)",
  "sample_size": null,
  "outcomes": [
    "mRNA/transcript levels of regulatory genes (egr-1, p21, c-jun, c-myc, hsp70, bcl-2) measured by semi-quantitative RT-PCR",
    "Gene expression changes during early stages of ES cell differentiation"
  ],
  "main_findings": "Intermittent 50 Hz power-line magnetic field exposure (5 min ON/30 min OFF) at 2.3 mT for 6 h significantly up-regulated c-jun, p21, and egr-1 mRNA levels in p53-deficient ES cells but not in wild-type ES cells. No significant effects were observed at lower flux densities, with longer exposure time, or after an 18 h recovery period.",
  "effect_direction": "mixed",
  "limitations": [
    "In vitro model (mouse ES cells) may not generalize to in vivo or human outcomes",
    "Sample size not reported in abstract",
    "Gene expression assessed by semi-quantitative RT-PCR (methodological detail limited in abstract)",
    "Effects depended on p53 status and specific intermittency/flux density conditions; other exposure conditions showed no significant effects"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF-EMF",
    "50 Hz",
    "power-line magnetic field",
    "PL-MF",
    "non-thermal effects",
    "embryonic stem cells",
    "p53",
    "gene expression",
    "intermittent exposure",
    "RT-PCR",
    "c-jun",
    "p21",
    "egr-1"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.25,
      "reason": "Study simulates power-line (50 Hz) magnetic field exposure, which is relevant to power-line/utility-related exposure contexts."
    }
  ]
}

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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.mrgentox.2003.09.011
PubMed: 14706519

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