Detection of space radiation-induced double strand breaks as a track in cell nucleus

• Published in: Biochemical and biophysical research communications 2009-12, Vol.390 (3), p.485-488
• Main Authors: Ohnishi, Takeo, Takahashi, Akihisa, Nagamatsu, Aiko, Omori, Katsunori, Suzuki, Hiromi, Shimazu, Toru, Ishioka, Noriaki
• Format: Article
• Language: English
• Subjects: ANIMAL CELLS; BIOLOGICAL RADIATION EFFECTS; Cell Line, Tumor; CELL NUCLEI; Cell Nucleus - metabolism; Cell Nucleus - radiation effects; DNA Breaks, Double-Stranded; DNA damage; DOSE RATES; DOSEMETERS; DOSIMETRY; DSB; Energy Transfer; Extraterrestrial Environment; FREEZERS; Histones - analysis; Histones - metabolism; Humans; INTERNATIONAL SPACE STATION; IRON IONS; LET; LUMINESCENCE; PARTICLE TRACKS; Phosphorylation; RADIATION PROTECTION AND DOSIMETRY; Radiation, Ionizing; RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS; Space radiation; STRAND BREAKS; γH2AX
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2009.09.114

To identify DNA damage induced by space radiations such as the high linear energy transfer (LET) particles, phospho-H2AX (γH2AX) foci formation was analyzed in human cells frozen in an International Space Station freezer for 133 days. After recovering the frozen sample to the earth, the cells were cultured for 30 min, and then fixed. Here we show a track of γH2AX positive foci in them by immuno-cytochemical methods. It is suggested that space radiations, especially high LET particles, induced DSBs as a track. From the formation of the tracks in nuclei, exposure dose rate was calculated to be 0.7 mSv per day as relatively high-energy space radiations of Fe-ions (500 MeV/u, 200 keV/μm). From the physical dosimetry with CR-39 plastic nuclear track detectors and thermo-luminescent dosimeters, dose rate was 0.5 mSv per day. These values the exposed dose rate were similar between biological and physical dosimetries.