The study of the DNA damage response in erythrocytes after g-irradiation may provide evidence for its
effectiveness as a biomarkers for genotoxic environmental stress. We previously reported various malformations
in erythrocytes of medaka irradiated with10 Gy, but not in their micronuclei. In this study, we
optimized an assay method for g-H2AX and double strand breaks in erythrocytes of adult medaka fish
after 15 Gy of g-irradiation. The highest level of apoptosis and nuclear abnormalities, including in
micronuclei, were recorded 4 h after g-irradiation, as was the highest level of g-H2AX foci in erythrocytes.
These results suggest that recognition and repair processes occur as a response to DNA damage in
erythrocytes in medaka.