title: Radiation-induced bystander effects enhanced by elevated sodium chloride through sensitizing cells to bystander factors.
abstract: Radiation-induced bystander effects (RIBE) have been demonstrated to occur widely in various cell lines. However, very little data is available on the genotoxic effects of RIBE combined with other factor(s). We reported previously that with a low dose of alpha-particle irradiation, the fraction of gamma-H2AX foci-positive cells in non-irradiated bystander cells was significantly increased under elevated NaCl culture conditions. In this study, we further investigated the functional role of NaCl in the enhancement of RIBE using a specially designed co-culture system and micronucleus (MN) test. It was shown that the MN frequency was not increased significantly by elevated NaCl (9.0 g/L) alone or by medium exposure. However, with 1.0 cGy alpha-particle irradiation, the induced MN frequency increased significantly in both irradiated and non-irradiated bystander regions. Additional studies showed that elevated NaCl made the non-irradiated bystander cells more vulnerable to bystander factors. Furthermore, it was found that the induced MN frequency in cells both in irradiated and non-irradiated bystander regions was weakened when the hypertonic medium was changed to normotonic medium for 2h before irradiation. Such observations were quite similar to the co-effect of NaCl and hydrogen peroxide (H(2)O(2)), indicating that elevated NaCl might sensitize non-irradiated cells to bystander factors-induced oxidative stress.
authors.affiliation: Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, Anhui, People's Republic of China.
authors.forename: Lingyan
authors.initials: L
authors.lastname: Zhu
authors.forename: Wei
authors.initials: W
authors.lastname: Han
authors.forename: Shaopeng
authors.initials: S
authors.lastname: Chen
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhao
authors.forename: Erkang
authors.initials: E
authors.lastname: Jiang
authors.forename: Lingzhi
authors.initials: L
authors.lastname: Bao
authors.forename: Bei
authors.initials: B
authors.lastname: Pei
authors.forename: Gen
authors.initials: G
authors.lastname: Yang
authors.forename: Guoping
authors.initials: G
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: An
authors.initials: A
authors.lastname: Xu
authors.forename: Lijun
authors.initials: L
authors.lastname: Wu
mesh_terms: D000512:Alpha Particles / Q000009:adverse effects; D024201:Bystander Effect / Q000187:drug effects* / Q000235:genetics / Q000528:radiation effects*; D002460:Cell Line; D018920:Coculture Techniques; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D007552:Isotonic Solutions; D015162:Micronucleus Tests; D018384:Oxidative Stress / Q000187:drug effects / Q000528:radiation effects; D012462:Saline Solution, Hypertonic; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D007552:Isotonic Solutions; D012462:Saline Solution, Hypertonic; D012965:Sodium Chloride; D006861:Hydrogen Peroxide