Extremely low frequency electromagnetic field exposure promotes differentiation of pituitary corticotrope-derived AtT20 D16V cells.

Bioelectromagnetics · 2006 · Benefit · Low evidence

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BenefitLow evidencePaper 5117

Study snapshot

PublicationBioelectromagnetics · 2006

Study typein_vitro

Reported directionBenefit

Evidence ratingLow

Abstract

The pituitary corticotrope-derived AtT20 D16V cell line responds to nerve growth factor (NGF) by extending neurite-like processes and differentiating into neurosecretory-like cells. The aim of this work is the study of the effect of extremely low frequency electromagnetic fields (ELF-EMF) at a frequency of 50 Hz on these differentiation activities. To establish whether exposure to the field could influence the molecular biology of the cells, they were exposed to a magnetic flux density of 2 milli-Tesla (mT). Intracellular calcium ([Ca2+]i) and intracellular pH (pHi) were monitored in single exposed AtT20 D16V cells using fluorophores Indo-1 and SNARF for [Ca2+]i and pHi, respectively. Single-cell fluorescence microscopy showed a statistically significant increase in [Ca2+]i followed by a drop in pHi in exposed cells. Both scanning electron microscopy (SEM) and transmission microscopy of exposed AtT20 D16V cells show morphological changes in plasma membrane compared to non-exposed cells; this modification was accompanied by a rearrangement in actin filament distribution and the emergence of properties typical of peptidergic neuronal cells-the appearance of secretory-like granules in the cytosol and the increase of synaptophysin in synaptic vesicles, changes typical of neurosecretory-like cells. Using a monoclonal antibody toward the neurofilament protein NF-200 gave additional evidence that exposed cells were in an early stage of differentiation compared to control. Pre-treatment with 0.3 microM nifedipine, which specifically blocks L-type Ca2+ channels, prevented NF-200 expression in AtT20 D16V exposed cells. The above findings demonstrate that exposure to 50 Hz ELF-EMF is responsible for the premature differentiation in AtT20 D 16 V cells.

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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 directionbenefit

PopulationPituitary corticotrope-derived AtT20 D16V cell line (mouse)

Sample sizeNot supplied

ExposureELF · 0.05 MHz

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

AtT20 D16V cells exposed to 50 Hz ELF-EMF at 2 mT showed a statistically significant increase in intracellular calcium followed by a drop in intracellular pH. Exposed cells exhibited membrane and cytoskeletal changes and increased markers/features consistent with early neurosecretory-like differentiation (e.g., secretory-like granules, increased synaptophysin, NF-200 immunoreactivity), and nifedipine pre-treatment prevented NF-200 expression in exposed cells.

Outcomes measured

Cell differentiation (neurosecretory-like features)
Intracellular calcium ([Ca2+]i)
Intracellular pH (pHi)
Plasma membrane morphology
Actin filament distribution
Secretory-like granules in cytosol
Synaptophysin in synaptic vesicles
Neurofilament protein NF-200 expression
Effect of L-type Ca2+ channel blocker (nifedipine) on NF-200 expression

Limitations

In vitro cell-line study; relevance to in vivo or human health outcomes not addressed in abstract
Exposure duration not reported in abstract
Sample size/replication details not reported in abstract

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Pituitary corticotrope-derived AtT20 D16V cell line (mouse)",
  "sample_size": null,
  "outcomes": [
    "Cell differentiation (neurosecretory-like features)",
    "Intracellular calcium ([Ca2+]i)",
    "Intracellular pH (pHi)",
    "Plasma membrane morphology",
    "Actin filament distribution",
    "Secretory-like granules in cytosol",
    "Synaptophysin in synaptic vesicles",
    "Neurofilament protein NF-200 expression",
    "Effect of L-type Ca2+ channel blocker (nifedipine) on NF-200 expression"
  ],
  "main_findings": "AtT20 D16V cells exposed to 50 Hz ELF-EMF at 2 mT showed a statistically significant increase in intracellular calcium followed by a drop in intracellular pH. Exposed cells exhibited membrane and cytoskeletal changes and increased markers/features consistent with early neurosecretory-like differentiation (e.g., secretory-like granules, increased synaptophysin, NF-200 immunoreactivity), and nifedipine pre-treatment prevented NF-200 expression in exposed cells.",
  "effect_direction": "benefit",
  "limitations": [
    "In vitro cell-line study; relevance to in vivo or human health outcomes not addressed in abstract",
    "Exposure duration not reported in abstract",
    "Sample size/replication details not reported in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF-EMF",
    "50 Hz",
    "2 mT",
    "AtT20 D16V",
    "pituitary corticotrope",
    "differentiation",
    "intracellular calcium",
    "intracellular pH",
    "synaptophysin",
    "NF-200",
    "nifedipine",
    "L-type Ca2+ channels"
  ],
  "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: 10.1002/bem.20255
PubMed: 16838272

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