Hsp70 expression and free radical release after exposure to non-thermal radio-frequency electromagnetic fields and ultrafine particles in human Mono Mac 6 cells.

Toxicology letters · 2006 · No effect · Low evidence

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No effectLow evidencePaper 5149

Study snapshot

PublicationToxicology letters · 2006

Study typein_vitro

Reported directionNo effect

Evidence ratingLow

Abstract

The contemporary urban environment has become increasingly complex in its composition, leading to discussions regarding possible novel health effects. Two factors that recently have received considerable attention are ultrafine particles (UFP; <0.1 microm) produced by combustion processes and emissions from wireless communication devices like mobile phones that emit in the radio-frequency (RF) part of the spectrum. Several studies have shown biological effects of both these exposures in various cell systems. Here we investigate if exposure to UFP (12-14 nm, 100 microg/ml) and RF-electromagnetic fields (EMF; 2 W/kg specific absorption rate (SAR); continuous wave (CW) or modulated (217Hz or GSM-nonDTX)), alone or in combination influences levels of the superoxide radical anion or the stress protein heat-shock protein (Hsp70) in the human monocyte cell line Mono Mac 6. Heat treatment (42-43 degrees C, 1h) was used as positive control for both stress reaction and for heat development in the RF exposure setup. Our results clearly show that Mono Mac 6 cells are capable to internalise UFP, and that this phagocytic activity is connected to an increased release of free radicals. This increase (40-45% above negative control) is stronger than the effect of heat treatment. On the other hand, none of the employed RF exposures showed any effects on free radical levels. Co-exposure of RF and UFP did not potentiate the UFP effect either. Our investigations showed a significantly increased Hsp70 expression level by heat treatment in a time-dependent manner, whereas UFP, RF, or UFP+RF were without any effect. Therefore, we conclude that in the investigated Mono Mac 6 cells, RF exposure alone or in combination with UFP cannot influence stress-related responses.

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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 directionno_effect

PopulationHuman monocyte cell line Mono Mac 6

Sample sizeNot supplied

ExposureRF · 2 W/kg

Evidence strengthLowConfidence: 86% · Peer reviewed: yes

Main findings

Mono Mac 6 cells internalised ultrafine particles (12–14 nm; 100 µg/ml), and this was associated with increased free radical release (40–45% above negative control). None of the RF-EMF exposures (2 W/kg SAR; continuous wave or modulated at 217 Hz or GSM-nonDTX) affected free radical levels, and RF co-exposure did not potentiate the UFP effect. Heat treatment increased Hsp70 expression in a time-dependent manner, while UFP, RF, and UFP+RF showed no effect on Hsp70.

Outcomes measured

Superoxide radical anion / free radical levels
Hsp70 (heat-shock protein 70) expression
Ultrafine particle internalisation (phagocytosis)

Limitations

In vitro study in a single human cell line (Mono Mac 6).
Exposure duration not reported in the abstract.
Sample size/replication details not reported in the abstract.
Findings pertain to the specific endpoints measured (free radicals and Hsp70) under the stated exposure conditions.

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "RF",
    "source": "mobile phone-like (GSM)",
    "frequency_mhz": null,
    "sar_wkg": 2,
    "duration": null
  },
  "population": "Human monocyte cell line Mono Mac 6",
  "sample_size": null,
  "outcomes": [
    "Superoxide radical anion / free radical levels",
    "Hsp70 (heat-shock protein 70) expression",
    "Ultrafine particle internalisation (phagocytosis)"
  ],
  "main_findings": "Mono Mac 6 cells internalised ultrafine particles (12–14 nm; 100 µg/ml), and this was associated with increased free radical release (40–45% above negative control). None of the RF-EMF exposures (2 W/kg SAR; continuous wave or modulated at 217 Hz or GSM-nonDTX) affected free radical levels, and RF co-exposure did not potentiate the UFP effect. Heat treatment increased Hsp70 expression in a time-dependent manner, while UFP, RF, and UFP+RF showed no effect on Hsp70.",
  "effect_direction": "no_effect",
  "limitations": [
    "In vitro study in a single human cell line (Mono Mac 6).",
    "Exposure duration not reported in the abstract.",
    "Sample size/replication details not reported in the abstract.",
    "Findings pertain to the specific endpoints measured (free radicals and Hsp70) under the stated exposure conditions."
  ],
  "evidence_strength": "low",
  "confidence": 0.86,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency",
    "RF-EMF",
    "GSM",
    "specific absorption rate",
    "SAR 2 W/kg",
    "continuous wave",
    "217 Hz modulation",
    "ultrafine particles",
    "UFP",
    "Mono Mac 6",
    "monocyte cell line",
    "superoxide",
    "free radicals",
    "Hsp70",
    "heat shock protein"
  ],
  "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.toxlet.2005.08.005
PubMed: 16153791

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