title: Hypoxia relieves X-ray-induced delayed effects in normal human embryo cells.
abstract: We studied the effect of hypoxia on X-ray-induced delayed effects in normal human embryo cells to elucidate the role of oxidative stress in the susceptibility of cells to induction of genetic instability by radiation. We examined X-ray-induced delayed cell death, giant cell formation, and chromosome aberrations under normally oxygenated (20%) and hypoxic (2%) conditions at 28-38 population doublings postirradiation. The results revealed that hypoxia reduced the X-ray-induced delayed effects, suggesting that radiation enhances cellular oxidative stress, which plays a significant role in determining the susceptibility of irradiated cells to genetic instability. The present study emphasizes the biological significance of epigenetic effects, such as oxygen tension, as well as direct DNA damage in the induction of genetic instability by radiation.
authors.affiliation: Department of Health Sciences, School of Pharmaceutical Sciences, Nagasaki University, Bunkyo-machi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Roy
authors.forename: S
authors.initials: S
authors.lastname: Kodama
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Fukase
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D002452:Cell Count; D016923:Cell Death / Q000187:drug effects / Q000528:radiation effects; D015687:Cell Hypoxia / Q000502:physiology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002869:Chromosome Aberrations; D002999:Clone Cells / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects*; D015726:Giant Cells / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D006801:Humans; D018384:Oxidative Stress / Q000502:physiology; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology; D011836:Radiation Tolerance / Q000187:drug effects; D014965:X-Rays
chemical_list: D010100:Oxygen