Frozen human cells can record radiation damage accumulated during space flight: Mutation induction and radioadaptation

Fumio Yatagai, Masamitsu Honma, Akihisa Takahashi, Katsunori Omori, Hiromi Suzuki, Toru Shimazu, Masaya Seki, Toko Hashizume, Akiko Ukai, Kaoru Sugasawa, Tomoko Abe, Naoshi Dohmae, Shuichi Enomoto, Takeo Ohnishi, Alasdair Gordon, Noriaki Ishioka

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


To estimate the space-radiation effects separately from other space-environmental effects such as microgravity, frozen human lymphoblastoid TK6 cells were sent to the "Kibo" module of the International Space Station (ISS), preserved under frozen condition during the mission and finally recovered to Earth (after a total of 134 days flight, 72 mSv). Biological assays were performed on the cells recovered to Earth. We observed a tendency of increase (2.3-fold) in thymidine kinase deficient (TK -) mutations over the ground control. Loss of heterozygosity (LOH) analysis on the mutants also demonstrated a tendency of increase in proportion of the large deletion (beyond the TK locus) events, 6/41 in the in-flight samples and 1/17 in the ground control. Furthermore, in-flight samples exhibited 48% of the ground-control level in TK - mutation frequency upon exposure to a subsequent 2 Gy dose of X-rays, suggesting a tendency of radioadaptation when compared with the ground-control samples. The tendency of radioadaptation was also supported by the post-flight assays on DNA double-strand break repair: a 1.8- and 1.7-fold higher efficiency of in-flight samples compared to ground control via non-homologous end-joining and homologous recombination, respectively. These observations suggest that this system can be used as a biodosimeter, because DNA damage generated by space radiation is considered to be accumulated in the cells preserved frozen during the mission, Furthermore, this system is also suggested to be applicable for evaluating various cellular responses to low-dose space radiation, providing a better understanding of biological space-radiation effects as well as estimation of health influences of future space explores.

Original languageEnglish
Pages (from-to)125-134
Number of pages10
JournalRadiation and Environmental Biophysics
Issue number1
Publication statusPublished - Mar 2011

ASJC Scopus subject areas

  • Biophysics
  • Radiation
  • Environmental Science(all)


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