DNA damage induced by space radiation including heavy-ion particles and its repair

2015 Fiscal Year Final Research Report

• Project/Area Number: 25514007
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: 宇宙生命学
• Research Institution: Nara Medical University
• Principal Investigator: Ohnishi Takeo 奈良県立医科大学, 医学部, 研究員 (60094554)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 宇宙放射線 / 重粒子線 / DNA 損傷 / DNA 修復 / 生物影響 / 細胞死 / 幹細胞

Outline of Final Research Achievements

To investigate how normal stem cells respond to low-dose heavy ion particles which are included in space radiations, the ICR mice were irradiated with carbon-ion beams at 0.01-5Gy. After irradiation, the apoptosis in small intestine and testis cells were observed dose-dependently even in the small dose range of 0.01 - 0.05 Gy. The hyper-radio-sensitivity at low-dose in the bone marrow stem and progenitor cells was observed 1 days after irradiation with the carbon-ion beams at less than 0.5Gy. The surviving curve at greater than 0.5Gy indicated the feature of linear quadratic model with a big shoulder. However, the reduction of surviving fractions was completely recovered in the bone marrow cells 14 days after irradiation at less than 1Gy.
These findings suggest that homologous recombination repair may be preferentially functioned to heavy ion-induced DNA damage less than 1Gy.　These results might contribute to protect space-radiation effects including heavy ion particles.

Free Research Field

放射線生物学