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Published on: June 5, 2020
Genotoxicity of intermediate frequency magnetic fields in vitro and in vivo
Mikko Herrala1, Kajal Kumari1, Hennariikka Koivisto2
1Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland.
Abstract:
We assessed genotoxic effects of intermediate frequency magnetic fields (MF) in vitro and in vivo. Rat primary astrocytes were exposed for 24 h to a 7.5 kHz MF at a magnetic flux density of 30 or 300 µT. Male C57BL/6 J mice were exposed continuously for 5 weeks to a 7.5 kHz MF at 12 or 120 μT, and blood samples were collected for the genotoxicity assays. To evaluate possible co-genotoxicity, the in vitro experiments included combined exposure with menadione (an agent that induces mitochondrial superoxide production and DNA damage) and methyl methanesulfonate (an alkylating agent). DNA damage and DNA repair (in vitro) were measured using the alkaline Comet assay and formation of micronuclei was assessed microscopically (in vivo) or using flow cytometry (in vitro). The results did not support genotoxicity or co-genotoxicity of 7.5 kHz MFs at magnetic flux densities up to 300 µT in vitro or in vivo. On the contrary, there was some evidence that exposure to 7.5 kHz MFs might reduce the level of genetic damage. Strongest indication of any biological effects was obtained from measurements of relative cell number, which was significantly and consistently increased after MF exposure in all in vitro experiments. Health implications of this finding are unclear, but it suggests that 7.5 kHz MFs may stimulate cell proliferation or suppress cell death.
Insights
Intermediate frequency magnetic fields (MF) did not show genotoxic effects in vitro or in vivo. Exposure to 7.5 kHz MF may even reduce genetic damage and stimulate cell proliferation.
Area of Science:
- Electromagnetism and Toxicology
- Cell Biology and Molecular Genetics
Background:
- Concerns exist regarding potential health risks of intermediate frequency magnetic fields (MF).
- Genotoxicity assessment is crucial for understanding biological effects of MF exposure.
Purpose of the Study:
- To evaluate the genotoxic and co-genotoxic potential of 7.5 kHz MF exposure in vitro and in vivo.
- To investigate the effects of MF on DNA damage and repair mechanisms.
Main Methods:
- In vitro: Rat primary astrocytes exposed to 7.5 kHz MF (30 or 300 µT) with or without menadione/methyl methanesulfonate. Assessed DNA damage, DNA repair, and micronuclei formation via alkaline Comet assay and flow cytometry.
- In vivo: Male C57BL/6J mice exposed to 7.5 kHz MF (12 or 120 µT) for 5 weeks. Assessed genotoxicity via blood micronuclei formation.
Main Results:
- No evidence of genotoxicity or co-genotoxicity was found for 7.5 kHz MF up to 300 µT in vitro or in vivo.
- Some evidence suggested MF exposure might reduce existing genetic damage.
- A significant increase in relative cell number was observed in vitro, suggesting MF may stimulate cell proliferation or suppress cell death.
Conclusions:
- 7.5 kHz MF exposure at tested parameters does not induce genotoxicity.
- MF exposure may have a protective effect against genetic damage and influence cell proliferation or death.
- Further research is needed to clarify the health implications of observed cellular effects.
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