title: Relief of delayed oxidative stress by ascorbic acid can suppress radiation-induced cellular senescence in mammalian fibroblast cells.
abstract: Ionizing radiation-induced cellular senescence is thought to be caused by nuclear DNA damage that cannot be repaired. However, here we found that radiation induces delayed increase of intracellular oxidative stress after irradiation. We investigated whether the relief of delayed oxidative stress by ascorbic acid would suppress the radiation-induced cellular senescence in Syrian golden hamster embryo (SHE) cells. We observed that the level of oxidative stress was drastically increased soon after irradiation, then declined to the level in non-irradiated cells, and increased again with a peak on day 3 after irradiation. We found that the inductions of cellular senescence after X-irradiation were reduced along with suppression of the delayed induction of oxidative stress by treatment with ascorbic acid, but not when oxidative stress occurred immediately after irradiation. Moreover, treatment of ascorbic acid inhibited p53 accumulation at 3 days after irradiation. Our data suggested a delayed increase of intracellular oxidative stress levels plays an important role in the process of radiation-induced cellular senescence by p53 accumulation.
authors.affiliation: Department of Radiology, School of Medicine, Oita University, Oita, Japan. Electronic address: kobashin@oita-u.ac.jp.
authors.forename: Shinko
authors.initials: S
authors.lastname: Kobashigawa
authors.affiliation: Advanced Molecular Imaging Center, School of Medicine, Oita University, Oita, Japan.
authors.forename: Genro
authors.initials: G
authors.lastname: Kashino
authors.affiliation: Department of Radiology, School of Medicine, Oita University, Oita, Japan.
authors.forename: Hiromu
authors.initials: H
authors.lastname: Mori
authors.affiliation: Radiation Biology Center, Kyoto University, Kyoto, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000187:drug effects* / Q000528:radiation effects*; D006224:Cricetinae; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D008647:Mesocricetus; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects*; D014965:X-Rays / Q000009:adverse effects*
chemical_list: D001205:Ascorbic Acid
keywords: Ascorbic acid; Ionizing radiation; Oxidative stress; Radiation-induced cellular senescence