Direct and indirect effects of exposure to 900 MHz GSM RF EMF on CHO cell line: Evidence of bystander effect

2019 · Mixed · Low evidence

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MixedLow evidencePaper 1833

Study snapshot

Publicationmanual · 2019

Study typein_vitro

Reported directionMixed

Evidence ratingLow

Abstract

Direct and indirect effects of exposure to 900 MHz GSM RF EMF on CHO cell line: Evidence of bystander effect by non-ionizing radiation Jooyan N, Goliaei B, Bigdeli B, Faraji-Dana R, Zamani A, Entezami M, Mortazavi SMJ. Direct and indirect effects of exposure to 900 MHz GSM radiofrequency electromagnetic fields on CHO cell line: Evidence of bystander effect by non-ionizing radiation. Environ Res. 2019 Apr 1. pii: S0013-9351(19)30197-5. doi: 10.1016/j.envres.2019.03.063. Highlights • Short-term exposure to radiofrequency radiation (RFR) emitted from mobile phones may cause genotoxic effects. • RFR has both targeted and non-targeted effects on cells. • RFR-induced non-targeted effects include bystander effect. • The biological effects of RFR are possibly mediated by oxidative stress. • Extracellular ROS can trigger molecular signals in non-targeted cells. Abstract INTRODUCTION: The rapid rise in global concerns about the adverse health effects of exposure to radiofrequency radiation (RFR) generated by common devices such as mobile phones has prompted scientists to further investigate the biological effects of these environmental exposures. Non-targeted effects (NTEs) are responses which do not need a direct exposure to be expressed and are particularly significant at low energy radiations. Although NTEs of ionizing radiation are well documented, there are scarcely any studies on non- targeted responses such as bystander effect (BE) after exposure to non-ionizing radiation. The main goal of this research is to study possible RFR-induced BE. MATERIAL AND METHODS: Chinese hamster ovary cells were exposed to 900 MHz GSM RFR at an average specific absorption rate (SAR) of 2 W/kg for 4, 12 and 24 hours (h). To generate a uniformly distributed electromagnetic field and avoid extraneous RF exposures a cavity was desined and used. Cell membrane permeability, cell redox activity, metabolic and mitotic cell death and DNA damages were analyzed. Then the most effective exposure durations and statistically significant altered parameters were chosen to assess the induction of BE through medium transfer procedure. Furthermore, intra and extra cellular reactive oxygen species (ROS) levels were measured to assess the molecular mechanism of BE induced by non-ionizing radiation. RESULTS: No statistically significant alteration was found in cell membrane permeability, cell redox activity, metabolic cell activity and micronuclei (MN) frequency in the cells directly exposed to RFR for 4, 12, or 24 h. However, RFR exposure for 24 h caused a statistically significant decrease in clonogenic ability as well as a statistically significant increase in olive moment in both directly exposed and bystander cells which received media from RFR-exposed cells (conditioned culture medium; CCM). Exposure to RFR also statistically significant elevated both intra and extra cellular levels of ROS. CONCLUSION: Our observation clearly indicated the induction of BE in cells treated with CCM. To our knowledge, this is the first report that a non-ionizing radiation (900 MHz GSM RFR) can induce bystander effect. As reported for ionizing radiation, our results proposed that ROS can be a potential molecule in indirect effect of RFR. On the other hand, we found the importance of ROS in direct effect of RFR but in different ways. ncbi.nlm.nih.gov

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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

PopulationCHO (Chinese hamster ovary) cell line

Sample sizeNot supplied

ExposureRF · 900 MHz · 2 W/kg · 4, 12, and 24 hours

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In directly exposed cells, no statistically significant changes were found in membrane permeability, redox activity, metabolic activity, or micronuclei frequency after 4, 12, or 24 h exposure. After 24 h exposure, clonogenic ability decreased and DNA damage (olive moment) increased in both directly exposed cells and bystander cells receiving conditioned medium from exposed cells; intracellular and extracellular ROS levels were also elevated.

Outcomes measured

cell membrane permeability
cell redox activity
metabolic cell activity
mitotic cell death
DNA damage (olive moment)
micronuclei (MN) frequency
clonogenic ability
intracellular ROS
extracellular ROS
bystander effect via conditioned culture medium (medium transfer)

Limitations

Sample size not reported in the provided abstract/metadata
In vitro cell-line study; generalizability to humans not addressed in the provided abstract
Only one frequency (900 MHz) and one average SAR (2 W/kg) reported
Bystander effect assessed via medium transfer; other indirect-effect pathways not described in the provided abstract

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 900,
    "sar_wkg": 2,
    "duration": "4, 12, and 24 hours"
  },
  "population": "CHO (Chinese hamster ovary) cell line",
  "sample_size": null,
  "outcomes": [
    "cell membrane permeability",
    "cell redox activity",
    "metabolic cell activity",
    "mitotic cell death",
    "DNA damage (olive moment)",
    "micronuclei (MN) frequency",
    "clonogenic ability",
    "intracellular ROS",
    "extracellular ROS",
    "bystander effect via conditioned culture medium (medium transfer)"
  ],
  "main_findings": "In directly exposed cells, no statistically significant changes were found in membrane permeability, redox activity, metabolic activity, or micronuclei frequency after 4, 12, or 24 h exposure. After 24 h exposure, clonogenic ability decreased and DNA damage (olive moment) increased in both directly exposed cells and bystander cells receiving conditioned medium from exposed cells; intracellular and extracellular ROS levels were also elevated.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in the provided abstract/metadata",
    "In vitro cell-line study; generalizability to humans not addressed in the provided abstract",
    "Only one frequency (900 MHz) and one average SAR (2 W/kg) reported",
    "Bystander effect assessed via medium transfer; other indirect-effect pathways not described in the provided abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "900 MHz",
    "GSM",
    "radiofrequency radiation",
    "RF EMF",
    "specific absorption rate",
    "SAR 2 W/kg",
    "CHO cells",
    "in vitro",
    "bystander effect",
    "non-targeted effects",
    "conditioned culture medium",
    "DNA damage",
    "olive moment",
    "clonogenic survival",
    "reactive oxygen species",
    "oxidative stress"
  ],
  "suggested_hubs": [
    {
      "slug": "mobile-phones",
      "weight": 0.9,
      "reason": "Exposure described as 900 MHz GSM RFR emitted from mobile phones."
    }
  ]
}

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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.envres.2019.03.063
PubMed: Not supplied

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