量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum and Radiological Science and Technology.
Thank you very much for using our website. On the 11th of March 2019, this site was moved from our own network server to the JAIRO Cloud network server. If you previously bookmarked this site, that bookmark will no longer work. We would be grateful if you could bookmark the website again. Thank you very much for your understanding and cooperation.
Adaptive response(AR) and bystander effect are two important phenomena involved in biological responses to low doses of ionizing radiation(IR). Furthermore, there is a strong interest in better understanding the biological effects of high-LET radiation. In this study, we assessed in vitro the ability of priming low doses (0.01-0.1 Gy) of X-rays and heavy-ion radiation to induce an AR to a subsequent challenging dose (1-4Gy) of high-LET IR(carbon-ion:20 and 40keV/mum, neon-ion : 150keV/mum) in cultured lymphoblastoid TK6, AHH-1 and NH32 cells. Pre-exposure of p53-competent cells (both with low-dose X-rays and high-LET IR) resulted in decreased mutation frequencies at Hypoxanthine-guanine phosphoribosyl transferase (HPRT) locus and different H2AX phosphorylation kinetics, as compared to cells exposed to challenging radiation alone. This phenominon was independent of radiation-induced apoptosis or cell cycle effects. Taken together, our results suggested the existence of an AR to mutagenic effects of heavy-ion radiation in lymphoblastoid cells and the involvement of double-strand break repair mechanisms.
Even though the cell directly hit by heavy-ion beams (even at low doses) are likely to suffer significant damage, our results constitute the first report to date indicating that low doses of high-LET radiation can nevertherless induce protective effects against subsequent high-LET irradiation. Taking inter-individual varianbility into account, these results might have interesting implications for high-LET radiation therapy and space research.
High-LET Heavy-Ion Radiation and Adaptive Response
