Chromosomal aberrations induced in Trp53-heterozygous mice exposed to both chronic restraint-induced stress and Fe-particle irradiation

Astronauts develop psychological stress (PS) during space flight because of enclosed environment, zero gravity and altered light-dark cycles. At the same time, they are exposed to cosmic rays including high atomic number and energy (HZE) particles such as iron-56 (Fe) ions. A pioneering study showed that chronic restraint-induced PS (CRIPS) could attenuate Trp53 functions and increase carcinogenesis induced by gamma-rays in Trp53-heterozygous (Trp53+/-) mice. To elucidate possible modification effects from CRIPS on HZE particles-induced health consequences, Trp53+/- C57BL/6N male mice (six-week-old) were restrained 6 hours per day for consecutive 28 days, and total-body irradiation (TBI) of Fe ions at a dose of 0.1 or 2 Gy was given on the 8th day. Chromosomal aberrations (CAs) in splenocytes were observed by fluorescence in situ hybridization (FISH) at the end of the 28-day restraint regimen. Induction of PS in our experimental model was confirmed by an increase in urinary corticosterone level. CRIPS reduced splenocyte number per spleen but Fe TBI. Fe TBI alone increased CAs significantly at 2.0 Gy. CRIPS alone didn’t induce CAs but concurrent exposure to CRIPS and 0.1 Gy Fe TBI showed a significant increase in the frequency of CAs as compared to exposure to Fe TBI alone. This work was partially supported by MEXT Grant-in-Aid for Scientific Research on Innovative Areas, “Living in Space” (JP15K21745, 15H05944 and 5H05935).日本宇宙生物科学会第33回大会に出席して「Chromosomal aberrations induced in Trp53-heterozygous mice exposed to both chronic restraint-induced stress and Fe-particle irradiation」のタイトルでポスター発表を行う