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Increased chromatid-type chromosomal aberrations in mouse m5S cells exposed to power-line frequency magnetic fields
H Yaguchi1, M Yoshida, G R Ding
1Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Japan.
Purpose:
To investigate the induction of chromosomal aberrations in mouse m5S cells after exposure to power-line frequency magnetic fields (extremely low frequency magnetic fields; ELFMF) at high-flux densities.
Material And Method:
m5S cells were either untreated or pretreated during the G1 phase with mitomycin C (MMC, 1 microM) for 1 h or 3 Gy X-rays, and then exposed to ELFMF at three different flux densities (5 and 50 mT at 60 Hz, 400 mT at 50 Hz) for 40 h. Unexposed control cells were incubated for the same period in a conventional CO2 incubator. Chromosomal aberrations were analysed in the first post-treatment metaphases. Cell kinetics were assessed by DNA flow cytometry and the mitotic index.
Results And Conclusions:
ELFMF enhanced the formation of spontaneous and MMC- or X-ray-induced chromosomal aberrations, in a flux-density-dependent manner. Statistically significant increases in the frequency of chromosomal aberrations were observed in cells exposed to 400 mT ELFMF with respect to unexposed controls. The aberrations induced by ELFMF were mostly chromatid-type, not chromosome-type. The cells exposed to 400 mT ELFMF exhibited a three-fold higher level of chromatid-type aberrations than did the unexposed cells. Flow cytometric and mitotic index analyses revealed that the S or G2 arrest following MMC or X-irradiation was more profound in ELFMF-exposed cells than in unexposed cells. Our results suggest that ELFMF can interfere with post-replication repair, resulting in increased levels of chromatid-type chromosomal aberrations induced spontaneously and by DNA damaging agents.
Insights
Exposure to high-flux power-line frequency magnetic fields (extremely low frequency magnetic fields; ELFMF) increased chromosomal aberrations in mouse cells. This effect was flux-density dependent and interfered with DNA repair mechanisms.
Area of Science:
- Cell Biology
- Genetics
- Biophysics
Background:
- Chromosomal aberrations are indicators of genetic damage.
- Extremely low frequency magnetic fields (ELFMF) are prevalent in the environment.
- Understanding ELFMF effects on cells is crucial for public health.
Purpose of the Study:
- To investigate the induction of chromosomal aberrations in mouse m5S cells exposed to ELFMF.
- To determine the influence of ELFMF flux density on genetic damage.
- To explore ELFMF's impact on DNA repair processes.
Main Methods:
- Mouse m5S cells were exposed to ELFMF at various flux densities (5, 50, and 400 mT) for 40 hours.
- Cells were treated with mitomycin C or X-rays to induce DNA damage.
- Chromosomal aberrations were analyzed, and cell kinetics were assessed via flow cytometry and mitotic index.
Main Results:
- ELFMF exposure enhanced spontaneous and induced chromosomal aberrations in a flux-density-dependent manner.
- A significant increase in aberrations was observed at 400 mT ELFMF compared to controls.
- ELFMF exposure led to a higher proportion of chromatid-type aberrations.
Conclusions:
- ELFMF can interfere with post-replication DNA repair.
- Increased chromatid-type chromosomal aberrations suggest ELFMF's genotoxic potential.
- Results indicate ELFMF's capacity to potentiate DNA damage induced by other agents.