title: Effective suppression of bystander effects by DMSO treatment of irradiated CHO cells.
abstract: Evidence is accumulating that irradiated cells produce some signals which interact with non-exposed cells in the same population via a bystander effect. Here, we examined whether DMSO is effective in suppressing radiation induced bystander effects in CHO and repair deficient xrs5 cells. When 1 Gy-irradiated CHO cells were treated with 0.5% DMSO for 1 hr before irradiation, the induction of micronuclei in irradiated cells was suppressed to 80% of that in non-treated irradiated cells. The suppressive effect of DMSO on the formation of bystander signals was examined and the results demonstrated that 0.5% DMSO treatment of irradiated cells completely suppressed the induction of micronuclei by the bystander effect in non-irradiated cells. It is suggested that irradiated cells ceased signal formation for bystander effects by the action of DMSO. To determine the involvement of reactive oxygen species on the formation of bystander signals, we examined oxidative stress levels using the DCFH staining method in irradiated populations. The results showed that the treatment of irradiated cells with 0.5% DMSO did not suppress oxidative stress levels. These results suggest that the prevention of oxidative stress is independent of the suppressive effect of DMSO on the formation of the bystander signal in irradiated cells. It is suggested that increased ROS in irradiated cells is not a substantial trigger of a bystander signal.
authors.affiliation: Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University. kashino@rri.kyoto-u.ac.jp
authors.forename: Genro
authors.initials: G
authors.lastname: Kashino
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Prise
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: Minoru
authors.initials: M
authors.lastname: Suzuki
authors.forename: Kenji
authors.initials: K
authors.lastname: Nagata
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kinashi
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Masunaga
authors.forename: Koji
authors.initials: K
authors.lastname: Ono
authors.forename: Masami
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D024201:Bystander Effect; D016466:CHO Cells; D018920:Coculture Techniques; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D004307:Dose-Response Relationship, Radiation; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects / Q000528:radiation effects*; D015233:Models, Statistical; D018384:Oxidative Stress; D015398:Signal Transduction; D014965:X-Rays
chemical_list: D004121:Dimethyl Sulfoxide