Genotoxicity was estimated by the number of apurinic/apyrimidinic sites in the genomic DNA. Apurinic/apyrimidinic sites of the DNA are common DNA lesions. The human glioblastoma cells were exposed to extremely low frequency magnetic fields alone and plus chemical mutagen (methyl methanesulfonate or hydrogen peroxide).
The applied magnetic flux density of 5 mT is ten times higher as the ICNIRP reference level.
cells were treated in six groups: i) exposure to EMF ii) exposure to methyl methanesulfonate (MMS) iii) exposure to EMF + exposure to MMS iv) exposure to hydrogen peroxide (H2O2) v) exposure to EMF + exposure to H2O2 vi) sham exposure
|Exposure duration||continuous for 2, 4, 8, 16 or 24 h|
The cell survival was signigicant different in cells exposed to extremely low frequency magnetic field compared to sham exposed cells from 2 to 24 hours exposure time. Treatment with chemical mutagens resulted in time dependent decrease in cell survival. The co-exposure with extremely low frequency magnetic field did not differ significantly from the cell survival in chemical mutagen alone treated cells.
No significant difference in the number of apurinic/apyrimidinic sites between exposed and sham exposed cells was observed.
The mutagen treatment alone increased the number of apurinic/apyrimidinic sites with longer treatment times. The co-exposure (extremely low frequency magnetic field exposure plus chemical mutagen) increased apurinic/apyrimidinic site levels compared with the chemical mutagens alone.
These data suggest that the number of apurinic/apyrimidinic sites induced by the chemical mutagens methyl methanesulfonate or hydrogen peroxide is enhanced by the exposure to extremely low frequency magnetic fields at 5 mT.