title: Time-varying magnetic fields of 60 Hz at 7 mT induce DNA double-strand breaks and activate DNA damage checkpoints without apoptosis.
abstract: The potential genotoxic effect of a time-varying magnetic field (MF) on human cells was investigated. Upon continuous exposure of human primary fibroblast and cervical cancer cells to a 60 Hz MF at 7 mT for 10-60 min, no significant change in cell viability was observed. However, deoxyribonucleic acid (DNA) double-strand breaks (DSBs) were detected, and the DNA damage checkpoint pathway was activated in these cells without programmed cell death (called apoptosis). The exposure of human cells to a 60 Hz MF did not induce intracellular reactive oxygen species (ROS) production, suggesting that the observed DNA DSBs are not directly caused by ROS. We also compared the position and time dependency of DNA DSBs with numerical simulation of MFs. The Lorentz force and eddy currents in these experiments were numerically calculated to investigate the influence of each factor on DNA DSBs. The DNA DSBs mainly occurred at the central region, where the MF was strongest, after a 30-min exposure. After 90 min, however, the amount of DNA DSBs increased rapidly in the outer regions, where the eddy current and Lorentz force were strong.
authors.affiliation: Department of Biochemistry, Yonsei University, Seoul, Korea.
authors.forename: Jiyeon
authors.initials: J
authors.lastname: Kim
authors.forename: Yeojun
authors.initials: Y
authors.lastname: Yoon
authors.forename: Seungho
authors.initials: S
authors.lastname: Yun
authors.forename: Gwan Soo
authors.initials: GS
authors.lastname: Park
authors.forename: Hae June
authors.initials: HJ
authors.lastname: Lee
authors.forename: Kiwon
authors.initials: K
authors.lastname: Song
mesh_terms: D017209:Apoptosis; D059447:Cell Cycle Checkpoints; D002470:Cell Survival; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D060526:Magnetic Fields / Q000009:adverse effects*; D013997:Time Factors