Figure 4

Mean number of radiation-induced γ-H2AX foci per CD34⁺ cell at 2 and 18 h post-irradiation with 0.5 Gy. The number of radiation-induced γ-H2AX foci was obtained by subtracting the mean number of γ-H2AX foci in the non-irradiated controls from the mean γ-H2AX foci number scored in the irradiated samples. The number of radiation-induced γ-H2AX foci was significantly different between ⁶⁰Co γ-rays (n = 6) and neutron (n = 9) radiation at 2 h (*p < 0.05), while after 18 h no significant difference (p > 0.05) was observed between the two radiation qualities. Error bars represent standard error of the mean (SEM).The images (A–D) on the right-side show immunofluorescence staining of γ-H2AX foci with a TRITC-conjugated secondary antibody (red). The foci represent the residual DNA DSBs at 2 h (A and C) and 18 h (B and D) after 0.5 Gy ⁶⁰Co γ-rays (A and B) and neutron irradiation (C and D).