Fig. 6

PARP expression and early apoptosis. Cells were exposed to 1 Gy radiation and analysed by Western blotting and flow cytometry after 0.5, 2, and 6 h. a Western blotting of PARP, cleaved PARP (c-PARP), and GAPDH. b Densitometric analysis shows the ratio of cleaved PARP to uncleaved PARP. c Annexin-V and 7-AAD were measured to assess the level of early apoptosis by flow cytometry. The Annexin-V- and 7-AAD-negative cell population is shown in the graph (± SEM). *P ˂ 0.05 versus control (Ctrl) within each group by one-way ANOVA and Tukey’s multiple comparison test). hDF human dermal fibroblast