Radiosensitization of heavy-ion beam based on modifying early phase redox reaction

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K07695
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: National Institutes for Quantum Science and Technology
• Principal Investigator: Matsumoto Ken-ichiro 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 放射線規制科学研究部, グループリーダー (10297046)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 放射線増感 / 重粒子線 / 炭素線 / 放射線生物影響 / 活性酸素 / 過酸化水素 / 紫外線 / ヒドロキシルラジカル

Outline of Final Research Achievements

Sensitization of biological effect of heavy-ion beam was tested by enzymatic or photochemical processing of hydrogen peroxide (H2O2) induced by heavy-ion beam in mice. A method of preparing selenium-deficient (SeD) model mouse, which has lacked glutathione peroxidase (GSH-Px) activity and can not decompose H2O2, was developed and reported. Effect of Se-deficiency on 30-day-lethality, leg contracture, and redox status in brain after X-ray and carbon-ion beam irradiation was investigated. Se-deficiency could exaggerate the 30-day-lethality of both X-ray and carbon-ion beam, however no marked difference on biological effects between X-ray and carbon-ion beam was observed. Effect of UVB irradiation after a carbon-ion irradiation to a mouse hind leg, which probably produce hydroxyl radical from H2O2, was investigated. The UVB irradiation immediately after carbon-ion beam irradiation increase the maximum length of leg contracture, and exaggerated rate constant of shortening.

Free Research Field

物理系薬学

Academic Significance and Societal Importance of the Research Achievements

セレン欠乏によりグルタチオンペルオキシダーゼの過酸化水素分解能を失活させた場合には、炭素線の生体影響の増感を組織単位で観察することはできなかった。しかし炭素線照射直後の組織への紫外線照射により、過酸化水素を分解してヒドロキシルラジカルの生成を試みたところ、炭素線の生物効果の増感が見られた。過酸化水素からヒドロキシルラジカルが発生する反応を促進すれば、重粒子線による過酸化水素の特徴ある分布に基づいて、腫瘍組織特異的に重粒子線の効果を増幅できる可能性が得られた。