Absence of DNA damage after 60-Hz electromagnetic field exposure combined with ionizing radiation, hydrogen peroxide, or c-Myc overexpression

Abstract

The principal objective of this study was to assess the DNA damage in a normal cell line system after exposure to 60 Hz of extremely low frequency magnetic field (ELF-MF) and particularly in combination with various external factors, via comet assays. NIH3T3 mouse fibroblast cells, WI-38 human lung fibroblast cells, L132 human lung epithelial cells, and MCF10A human mammary gland epithelial cells were exposed for 4 or 16 h to a 60-Hz, 1 mT uniform magnetic field in the presence or absence of ionizing radiation (IR, 1 Gy), H(2)O(2) (50 μM), or c-Myc oncogenic activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic or additive effects were observed after 4 or 16 h of pre-exposure to 1 mT ELF-MF or simultaneous exposure to ELF-MF combined with IR, H(2)O(2), or c-Myc activation.

The effects of extremely low frequency magnetic fields on mutation induction in mice

“…Similar to their earlier published data (Jin et al, 2012(Jin et al, , 2014, 1 mT ELF-MF in combination with 1 Gy X-rays, or H 2 O 2 or c-Myc activation did not potentiate the formation of γ-H2AX foci (Yoon et al, 2014). However, when the field strength was increased to 2 mT over the same duration (6 hours), a combination of ELF-MF and ionising radiation was capable of inducing γ-H2AX, yet both H 2 O 2 and cMyc remained incapable of this.…”

“…Similarly, a recent series of studies performed by the same laboratory demonstrated that 4 or 16 hour exposure to 60 Hz, 1 mT ELF-MF in combination with ionising radiation (1 Gy X-rays) or H 2 O 2 or cellular myelocytomatosis oncogene (c-Myc) activation did not have either an enhancing or synergistic effect on MN formation (Jin et al, 2012) or primary DNA damage (Jin et al, 2014). However, more recently the authors re-analysed the effects of ELF-MF exposure on DNA damage response in combination with the same mutagens through the formation of γ-H2AX…”

Effects of 60-Hz Magnetic Fields on DNA Damage Responses in HT22 Mouse Hippocampal Cell Lines

“…Our previous study showed that exposure to a 1-mT ELF-MF for a maximum of 24 hours did not show any increase in MN formation [12] or comet tail production in several cell lines [11]. However, when we examined γH2AX, a 2-mT ELF-MF significantly increased γH2AX [14].…”

“…Previously, we investigated the effects of ELF-MFs on DNA damage responses, such as cellular transformation [10], comet tail moments [11], micronuclei formation [12], aneuploidy formation [13], and γH2AX expression [14]. These investigations were performed using non-tumorigenic epithelial or fibroblast cell lines.…”

“…Especially, in the case of in vitro studies, cell-line differences, such as from organs of different origin, may be a key point for inconsistent results. We demonstrated previously that a 1-mT ELF-MF alone did not induce cellular transformation in NIH3T3 mouse fibroblast cells [10], nor were there comet tail moments [11], micronucleus production [12], aneuploidy formation [13], or γH2AX formation [14] in the mouse embryonic fibroblast NIH3T3 cells, WI38 human lung fibroblasts, or L132 human lung epithelial cells. However, a 2-mT ELF-MF increased γH2AX formation [14], even though aneuploidy formation was not altered [13].…”