Quantification of combined effects of radiation under continuous gamma-ray irradiation using medaka thymus.

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K12251
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 63020:Radiation influence-related
• Research Institution: National Institutes for Quantum Science and Technology
• Principal Investigator: Maruyama Kouichi 国立研究開発法人量子科学技術研究開発機構, 放射線医学研究所 計測・線量評価部, 主幹研究員 (70349033)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: メダカ / 胸腺 / 放射線 / 複合影響

Outline of Final Research Achievements

We have established a novel biosystem for quantifying radiation effects in real-time using thymus-visualizing living medaka. By observing the thymus after a single X-ray exposure, we can observe and analyze the radiation effects and recovery in a dose-dependent manner (Maruyama et al.,IJRB 2019).
Using this system, three different types of stress were confirmed to cause thymic atrophy in medaka. The thymic atrophy in medaka was significantly observed under circadian rhythm disorder and psychological stress. The chemical (NaAsO2) did not atrophy the thymus compared with the other stresses. The threshold of the thymic atrophy was revealed at lower doses under the stress of the circadian rhythm disorders and psychogenic stress.

Free Research Field

放射線生物学

Academic Significance and Societal Importance of the Research Achievements

これまでにマウスの拘束モデル下での放射線影響との複合影響の仕事はあり、より低い線量で放射線影響が出ることが示されている。しかしながら魚類においては同様の研究は行われていない。今回、申請者が構築している胸腺可視化モデルを使い、放射線以外のストレスでもストレスを定量することが示され、また、ストレス下での放射線の影響を調べ、日照リズム障害下や心因的ストレス下では、より低い線量で放射線影響を与えることが示された。