Enhanced effect of extremely low frequency electromagnetic fields (ELF-EMF) on the induced AP sites (Apurinic/apyrimidinic sites) by MMS (methyl methane sulfonate)

抄録

We measured the amount of AP sites (Apurinic/apyrimidinic sites) in human glioma A172 cells to investigate the effect of extremely low frequency electromagnetic fields (ELF-EMF) at 5 mT. The cells were exposed to ELF-EMF alone, MMS (Methyl methane sulfonate) alone, or ELF-EMF with MMS in medium. The duration of exposure was 2, 4, 8, 16 and 24 hours. After the exposure, the cells were collected by cell-scraper, washed with PBS, and then we extracted DNA from the cells. After isolating DNA, ARP (Aldehyde Reactive Probe) reagents were added to DNA. Then, AP sites were tagged with biotin residues, which could be quantified using avidin-biotin assay, followed by a colorimetric detection of 450 nm. The number of AP sites were determined by calibration curve of from 0 to 40ARP/10⁵bp in standard DNAs. There was no difference in the number of AP sites between ELF-EMF exposed cells and sham control. The level of AP sites was increased with extending the MMS treatment time. The combined treatment of ELF-EMF and MMS increased AP site levels on 4, 8, 16 and 24 h exposure compared with MMS treatment alone. In this study, the exposure of ELF-EMF alone may have no effect to produce AP site. However, AP sites induced by MMS might be enhanced by ELF-EMF exposure.