Extremely low-frequency electromagnetic fields affect transcript levels of neuronal differentiation-related genes in embryonic neural stem cells.

PloS one · 2014 · Mixed · Low evidence

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MixedLow evidencePaper 4702

Study snapshot

PublicationPloS one · 2014

Study typein_vitro

Reported directionMixed

Evidence ratingLow

Abstract

Previous studies have reported that extremely low-frequency electromagnetic fields (ELF-EMF) can affect the processes of brain development, but the underlying mechanism is largely unknown. The proliferation and differentiation of embryonic neural stem cells (eNSCs) is essential for brain development during the gestation period. To date, there is no report about the effects of ELF-EMF on eNSCs. In this paper, we studied the effects of ELF-EMF on the proliferation and differentiation of eNSCs. Primary cultured eNSCs were treated with 50 Hz ELF-EMF; various magnetic intensities and exposure times were applied. Our data showed that there was no significant change in cell proliferation, which was evaluated by cell viability (CCK-8 assay), DNA synthesis (Edu incorporation), average diameter of neurospheres, cell cycle distribution (flow cytometry) and transcript levels of cell cycle related genes (P53, P21 and GADD45 detected by real-time PCR). When eNSCs were induced to differentiation, real-time PCR results showed a down-regulation of Sox2 and up-regulation of Math1, Math3, Ngn1 and Tuj1 mRNA levels after 50 Hz ELF-EMF exposure (2 mT for 3 days), but the percentages of neurons (Tuj1 positive cells) and astrocytes (GFAP positive cells) were not altered when detected by immunofluorescence assay. Although cell proliferation and the percentages of neurons and astrocytes differentiated from eNSCs were not affected by 50 Hz ELF-EMF, the expression of genes regulating neuronal differentiation was altered. In conclusion, our results support that 50 Hz ELF-EMF induce molecular changes during eNSCs differentiation, which might be compensated by post-transcriptional mechanisms to support cellular homeostasis.

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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 directionmixed

PopulationPrimary cultured embryonic neural stem cells (eNSCs)

Sample sizeNot supplied

ExposureELF · 0.05 MHz · Various exposure times; specific condition reported: 3 days

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Exposure to 50 Hz ELF-EMF showed no significant changes in eNSC proliferation across multiple assays and no changes in transcript levels of cell cycle-related genes (P53, P21, GADD45). During induced differentiation, 50 Hz ELF-EMF exposure (reported condition: 2 mT for 3 days) was associated with down-regulation of Sox2 and up-regulation of Math1, Math3, Ngn1 and Tuj1 mRNA, while the percentages of Tuj1-positive neurons and GFAP-positive astrocytes were not altered.

Outcomes measured

Cell proliferation (cell viability/CCK-8, DNA synthesis/EdU incorporation, neurosphere diameter, cell cycle distribution by flow cytometry)
Transcript levels of cell cycle-related genes (P53, P21, GADD45)
Differentiation-related gene expression (Sox2, Math1, Math3, Ngn1, Tuj1 mRNA by real-time PCR)
Percentages of neurons (Tuj1-positive) and astrocytes (GFAP-positive) by immunofluorescence

Limitations

In vitro study (primary cultured eNSCs), limiting direct inference to in vivo brain development
Sample size not reported in abstract
Magnetic field intensities and exposure times described as varied, but detailed exposure matrix not provided in abstract

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": "Various exposure times; specific condition reported: 3 days"
  },
  "population": "Primary cultured embryonic neural stem cells (eNSCs)",
  "sample_size": null,
  "outcomes": [
    "Cell proliferation (cell viability/CCK-8, DNA synthesis/EdU incorporation, neurosphere diameter, cell cycle distribution by flow cytometry)",
    "Transcript levels of cell cycle-related genes (P53, P21, GADD45)",
    "Differentiation-related gene expression (Sox2, Math1, Math3, Ngn1, Tuj1 mRNA by real-time PCR)",
    "Percentages of neurons (Tuj1-positive) and astrocytes (GFAP-positive) by immunofluorescence"
  ],
  "main_findings": "Exposure to 50 Hz ELF-EMF showed no significant changes in eNSC proliferation across multiple assays and no changes in transcript levels of cell cycle-related genes (P53, P21, GADD45). During induced differentiation, 50 Hz ELF-EMF exposure (reported condition: 2 mT for 3 days) was associated with down-regulation of Sox2 and up-regulation of Math1, Math3, Ngn1 and Tuj1 mRNA, while the percentages of Tuj1-positive neurons and GFAP-positive astrocytes were not altered.",
  "effect_direction": "mixed",
  "limitations": [
    "In vitro study (primary cultured eNSCs), limiting direct inference to in vivo brain development",
    "Sample size not reported in abstract",
    "Magnetic field intensities and exposure times described as varied, but detailed exposure matrix not provided in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF-EMF",
    "50 Hz",
    "embryonic neural stem cells",
    "proliferation",
    "differentiation",
    "gene expression",
    "Sox2",
    "Math1",
    "Math3",
    "Ngn1",
    "Tuj1",
    "GFAP",
    "2 mT"
  ],
  "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: 10.1371/journal.pone.0090041
PubMed: 24595264

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