2023 Fiscal Year Final Research Report
Cellular responses for targeted cytoplasmic irradiation with X-ray microbeams produced by synchrotron radiation
| Project/Area Number |
21K12249
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 63020:Radiation influence-related
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| Research Institution | National Institutes for Quantum Science and Technology |
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Principal Investigator |
SUZUKI Masao 国立研究開発法人量子科学技術研究開発機構, 量子医科学研究所重粒子線治療研究部, 専門業務員 (70281673)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 放射光X線マイクロビーム / ヒト正常細胞 / 細胞質限定的照射 / 細胞核限定的照射 / バイスタンダー効果 / 放射線適応応答 / ギャップジャンクション / 細胞間情報伝達機構 |
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| Outline of Final Research Achievements |
Cellular response, such as bystander effect, is essential to investigate secondary carcinogenesis after radio-therapy and evaluate radiation risk such as the accident of Fukushima Daiichi Nuclear Power Plants. A microbeam-irradiation system is useful to study such cellular response.
We examined cell killing for targeted cell nuclear or cytoplasmic irradiation (0.092Gy) using X-ray microbeams, which was produced at Photon Factory, KEK. Cell survival was 100% irradiated with cytoplasmic irradiation alone. It was 79% irradiated with all cell nuclei alone, however, it was rising to 95% when 10% of cytoplasm was irradiated beforehand. When treating with a gap-junction inhibitor, the cell survival for targeted nuclear irradiation was around 73% with the presence or absence of the targeted cytoplasmic irradiation beforehand. The results clearly showed that the bystander effect through gap-junction mediated cell-to-cell communication plays an essential role of inducing radio-adaptive response.
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| Free Research Field |
放射線影響
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| Academic Significance and Societal Importance of the Research Achievements |
作業仮説である細胞質照射で誘導される細胞応答は、細胞核に放射線のエネルギーが付与された後に引き起こされるDNA損傷応答が生物影響の出発点であるとする放射線生物影響研究におけるセントラルドグマにチャレンジする研究であり、そこに礎を置いて構築された放射線防護体系の基本的概念である直線閾値無し仮説に対して、特に低線量域でのリスク曲線の再検討と新たな評価概念構築に結び付く。また東日本大震災に伴う原子力発電所事故に起因する放射性物質による環境汚染で問題となる放射性核種から放出される低LET電磁波放射線被ばくによる人体影響リスク評価をメカニズムを礎にした新たなロジックの構築を可能にする研究に発展する。
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