Magnetic fields enhance chemical-induced genotoxicity

 

The past thirty years have witnessed scientific and public debate about the possible carcinogenic effects of extremely low frequency (ELF) magnetic fields (MFs), which are present wherever electricity is transmitted or used, e.g., in the vicinity of power lines and various electric appliances. The complexity of this issue was also recognised by the International Agency for Research on Cancer (IARC) in 2002, when it classified ELF magnetic fields as possibly carcinogenic to humans. This evaluation was mainly based on rather consistent epidemiological findings showing an association between residential ELF MF exposure and childhood leukaemia. However, the underlying biophysical and biological mechanisms by which ELFMF might cause childhood leukaemia, or carcinogenicity in general, are still unknown.

 

A team of researchers at the Department of Environmental Science at the University of Eastern Finland has already earlier established that pre-exposure to ELF MF altered cancer-relevant cellular responses (cell cycle arrest, apoptosis) to menadione-induced DNA damage, but it did not include endpoints measuring actual genetic damage. In the present study, the team examined whether pre-exposure to ELF MF affects chemically induced DNA damage level, DNA repair rate, or micronucleus frequency in human SH-SY5Y neuroblastoma cells. Exposure to 50 Hz MF was conducted at 100 µT for 24 hours, followed by chemical exposure for 3 hours. The chemicals used for inducing DNA damage and subsequent micronucleus formation were menadione and methyl methanesulphonate (MMS). Pre-treatment with MF enhanced menadione-induced DNA damage, DNA repair rate, and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the results with MMS indicated similar effects, the differences were not statistically significant. No effects were observed after MF exposure alone.

The results confirm the team’s previous findings showing that pre-exposure to MFs as low as 100 µT alters cellular responses to menadione, and show that increased genotoxicity results from such interaction. The present findings also indicate that complementary data at several chronological points may be critical for understanding the MF effects on DNA damage, repair, and post-repair integrity of the genome.

For further information, please contact Researcher Jukka Luukkonen, email: jukka.luukkonen@uef.fi

 

 


Original article:
Luukkonen J, Liimatainen A, Höytö A, Juutilainen J, Naarala J (2011) Pre-Exposure to 50 Hz Magnetic Fields Modifies Menadione-Induced Genotoxic Effects in Human SH-SY5Y Neuroblastoma Cells. PLoS ONE 6(3): e18021. doi:10.1371/journal.pone.0018021

 

Artikkelin kirjoitusvuosi: 2011

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