Evaluate The Effect Of DNA Damage On Human Lens Epithelia Cells Induced By Power Frequency Magnetic Fields With Different Methods

Background Power frequency magnetic fields (PF MF) refer the extremely low frequency electromagnetic fields (ELF EMF) with frequency of 50 Hz. With the wide use of electric power for domestic and industrial appliances, PF MF exposure emitted by these appliances has been rapidly increased. Thus, assessing the health risk of PF MF exposure has become important and urgent as a public health problem. As genetic material, DNA is easy to be attacked by endogenous and exogenous factors, which results in DNA damage and genomic instability. Since DNA damage is associated with increased mutagenic and carcinogenic risk, to investigate the effects of PF MF on DNA damage becomes a key issue in the field of bioelectromagnetics. Despite of studies for 30 years, the results are controversial about the effects of ELF EMF on DNA damage.Objective To comprehensively and objectively evaluate the effect of PF MF on DNA damage, we have evaluated DNA damage on human lens epithelia cells induced by power frequency magnetic fields with different methods.Methods Human lens epithelia cells were exposed or sham-exposed to 50 Hz MF at an intensity of 0.4 mT for 2h,6h,12h,24h and 48h. The yH2AX foci formation assay (immunofluorescence, flow cytometry, western blotting) and comet assay were applied to detect DNA damage.4NQO and H2O2 treatment was used as positive control. The mean number of foci and the percentage of yH2AX foci positive cells were analyzed in yH2AX foci formation assay. yH2AX foci positive cells were examined by flow cytometry analysis. The protein level of yH2AX was examined by Western Blotting analysis. The tail length and tail moment as indicators of DNA damage level were analyzed by comet assay.Results yH2AX immunofluorescence analyses showed no significant difference in the mean number of foci per cell or the percentage of yH2AX foci positive cells between sham- and PF MF- exposure group at each time point (P>0.05). Flow cytometry analyses showed that the percentage of yH2AX foci positive cells was less than5%, and no significant difference was found in the percentage of yH2AX positive cells (P>0.05). Western Blotting showed that there was no significant difference in yH2AX protein level (P>0.05). The comet assay analyses showed that there were no significant differences in tail length and tail moment (P>0.05).Conclusion Under current exposure conditions, PF MF could not induce DNA damage in human lens epithelia cells.