Relationship between ion track structure and quality of cellular DNA damage

Wada, Seiichi*; Funayama, Tomoo; Sakashita, Tetsuya; Hamada, Nobuyuki*; Kakizaki, Takehiko*; Ito, Nobuhiko*; Kobayashi, Yasuhiko

CHO-K1 cells attached on ion track detector CR-39 were irradiated with the same LET value but different nuclide (C and Ne). DNA strand breaks were immunohistochemically detected with tdt for total breaks, and with H2AX antibody for double strand breaks only. The fluorescent signal observed in nuclei by immunochemistry was co-localized at the site of etched pit where the ion was traversed on the cell. To evaluate the spatial distribution of DNA damage, the diameter of the area of fluorescent signal was measured. The area of H2AX induced by C ion and Ne ion were not significantly different, however, the area of DNA strand breaks induced by Ne ion was larger than that induced by C ion. This result indicates that the difference of ion track structure influences the pattern of induction of DNA damage.