Measurements of alkali-labile DNA damage and protein-DNA crosslinks after 2450 MHz microwave and low-dose gamma irradiation in vitro.

Radiation research · 2004 · No effect · Low evidence

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No effectLow evidencePaper 6406

In C3H 10T(1/2) cells, 2 h exposure to 2450 MHz continuous-wave microwaves at SAR 1.9 W/kg did not produce detectable DNA damage in the comet assay and did not impede gamma-ray-induced DNA migration. Measurements specific to DNA-protein crosslinks showed no e…

Study snapshot

PublicationRadiation research · 2004

Study typein_vitro

Reported directionNo effect

Evidence ratingLow

Abstract

In vitro experiments were performed to determine whether 2450 MHz microwave radiation induces alkali-labile DNA damage and/or DNA-protein or DNA-DNA crosslinks in C3H 10T(1/2) cells. After a 2-h exposure to either 2450 MHz continuous-wave (CW) microwaves at an SAR of 1.9 W/kg or 1 mM cisplatinum (CDDP, a positive control for DNA crosslinks), C3H 10T(1/2) cells were irradiated with 4 Gy of gamma rays ((137)Cs). Immediately after gamma irradiation, the single-cell gel electrophoresis assay was performed to detect DNA damage. For each exposure condition, one set of samples was treated with proteinase K (1 mg/ml) to remove any possible DNA-protein crosslinks. To measure DNA-protein crosslinks independent of DNA-DNA crosslinks, we quantified the proteins that were recovered with DNA after microwave exposure, using CDDP and gamma irradiation, positive controls for DNA-protein crosslinks. Ionizing radiation (4 Gy) induced significant DNA damage. However, no DNA damage could be detected after exposure to 2450 MHz CW microwaves alone. The crosslinking agent CDDP significantly reduced both the comet length and the normalized comet moment in C3H 10T(1/2) cells irradiated with 4 Gy gamma rays. In contrast, 2450 MHz microwaves did not impede the DNA migration induced by gamma rays. When control cells were treated with proteinase K, both parameters increased in the absence of any DNA damage. However, no additional effect of proteinase K was seen in samples exposed to 2450 MHz microwaves or in samples treated with the combination of microwaves and radiation. On the other hand, proteinase K treatment was ineffective in restoring any migration of the DNA in cells pretreated with CDDP and irradiated with gamma rays. When DNA-protein crosslinks were specifically measured, we found no evidence for the induction of DNA-protein crosslinks or changes in amount of the protein associated with DNA by 2450 MHz CW microwave exposure. Thus 2-h exposures to 1.9 W/ kg of 2450 MHz CW microwaves did not induce measurable alkali-labile DNA damage or DNA-DNA or DNA-protein crosslinks.

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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

PopulationC3H 10T(1/2) cells (in vitro)

Sample sizeNot supplied

Exposuremicrowave · 2450 MHz · 1.9 W/kg · 2 h

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Outcomes measured

Alkali-labile DNA damage (single-cell gel electrophoresis/comet assay)
DNA migration parameters (comet length, normalized comet moment)
DNA-protein crosslinks (protein recovered with DNA; proteinase K sensitivity)
DNA-DNA crosslinks (inferred via DNA migration impediment)

Limitations

Sample size not reported in abstract
Only one cell line studied (C3H 10T(1/2))
Single exposure condition reported (2450 MHz CW, 1.9 W/kg, 2 h)
Endpoints limited to comet-assay-detectable alkali-labile damage and crosslinks assessed immediately after irradiation

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "microwave",
    "source": null,
    "frequency_mhz": 2450,
    "sar_wkg": 1.9,
    "duration": "2 h"
  },
  "population": "C3H 10T(1/2) cells (in vitro)",
  "sample_size": null,
  "outcomes": [
    "Alkali-labile DNA damage (single-cell gel electrophoresis/comet assay)",
    "DNA migration parameters (comet length, normalized comet moment)",
    "DNA-protein crosslinks (protein recovered with DNA; proteinase K sensitivity)",
    "DNA-DNA crosslinks (inferred via DNA migration impediment)"
  ],
  "main_findings": "In C3H 10T(1/2) cells, 2 h exposure to 2450 MHz continuous-wave microwaves at SAR 1.9 W/kg did not produce detectable DNA damage in the comet assay and did not impede gamma-ray-induced DNA migration. Measurements specific to DNA-protein crosslinks showed no evidence of induction or changes in protein associated with DNA after microwave exposure.",
  "effect_direction": "no_effect",
  "limitations": [
    "Sample size not reported in abstract",
    "Only one cell line studied (C3H 10T(1/2))",
    "Single exposure condition reported (2450 MHz CW, 1.9 W/kg, 2 h)",
    "Endpoints limited to comet-assay-detectable alkali-labile damage and crosslinks assessed immediately after irradiation"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "2450 MHz",
    "microwave",
    "continuous-wave",
    "SAR 1.9 W/kg",
    "in vitro",
    "C3H 10T(1/2) cells",
    "comet assay",
    "single-cell gel electrophoresis",
    "alkali-labile DNA damage",
    "DNA-protein crosslinks",
    "DNA-DNA crosslinks",
    "proteinase K",
    "gamma irradiation",
    "137Cs",
    "cisplatinum"
  ],
  "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: 10.1667/rr3122
PubMed: 14731069

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