What are the mediators of bystander response induced by irradiation of argon particles?

アルゴンイオン照射で誘発されるバイスタンダー応答の媒介因子は何か?

松本 英樹*; 冨田 雅典*; 大塚 健介*; 舟山 知夫; 小林 泰彦

Matsumoto, Hideki*; Tomita, Masanori*; Otsuka, Kensuke*; Funayama, Tomoo; Kobayashi, Yasuhiko

The radioadaptive response, radiation-induced bystander responses, low-dose radio-hypersensitivity, and genomic instability are specifically observed in response to low dose/low dose-rate radiation, and the mechanisms underlying these responses often involve biochemical/molecular signals that respond to targeted and non-targeted events. However, mechanisms of these phenomena are not fully known. To elucidate the mechanisms of radiation-induced bystander responses, we analyzed the formation of H2AX and pNBS1 foci after irradiation of a targeted cell with 460 MeV Ar microbeams. We found that the foci of H2AX and pNBS1 were formed in the unirradiated cells in the colony including the targeted cell 6 h after the irradiation and that this formation of these foci was almost completely suppressed by the addition of DMSO or Lindane. Also we found that the foci of H2AX and pNBS1 were formed in the unirradiated cells in the colonies not including the targeted cell 6 h after irradiation and that this formation of the foci was almost completely suppressed by the addition of aminoguanidine or c-PTIO. Our findings strongly suggested that ROS and NO may be actually initiators/mediators for evoking radiation-induced bystander responses.