title: Different involvement of radical species in irradiated and bystander cells.
abstract: OBJECTIVE
  To examine whether nitric oxide (NO) and other radical species are involved in radiation-induced bystander effects in normal human fibroblasts.
  
  
  METHODS
  Bystander effects were modeled by co-culture of non-irradiated cells with X-irradiated cells, and induction levels of micronuclei in co-cultured non-irradiated cells were examined. Three types of radical scavenger, 2-(4-carboxyphenyl)-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO), dimethylsulfoxide (DMSO) and ascorbic acid phosphoric ester magnesium salt (APM), were used to discover which types of radicals are involved in bystander responses.
  
  
  RESULTS
  When irradiated cells were treated with c-PTIO, known to be an NO scavenger, the induction of micronuclei in non-irradiated bystander cells was suppressed. On the other hand, bystander effects were most effectively suppressed when non-irradiated bystander cells were treated with ascorbic acid, known to be a scavenger of long lived radicals.
  
  
  CONCLUSIONS
  These results suggest that NO participates in bystander signal formation in irradiated cells but not in bystander cells that are receiving bystander signals.
authors.affiliation: Division of Radiation Biology, Department of Radiology and Radiation Biology, Course of Life Sciences and Radiation Research, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Harada
authors.forename: Genro
authors.initials: G
authors.lastname: Kashino
authors.forename: Keiji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Naoki
authors.initials: N
authors.lastname: Matsuda
authors.forename: Seiji
authors.initials: S
authors.lastname: Kodama
authors.forename: Masami
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D024201:Bystander Effect / Q000187:drug effects / Q000528:radiation effects*; D002460:Cell Line; D018920:Coculture Techniques; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects*; D016166:Free Radical Scavengers / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism*; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D005609:Free Radicals; D017382:Reactive Oxygen Species; D009569:Nitric Oxide