Fig. 4

Experiments in vitro. a Survival fraction of cell colony formation assay (n = 3, mean ± SD, single asterisk indicates P < 0.05 according to Student’s two-tailed t-test). b Photographs of cell colony formation assay. c Relative intensity of PI in each group (n = 3, mean ± SD, two asterisks indicate P < 0.01 according to Student’s two-tailed t-test). d Calcein-AM and PI staining of each group. e The yield of ·OH of each group measured by 2,7-Dichlorodi-hydrofluorescein diacetate (DCFH-DA) staining. f Cell γ-H2AX staining of each group. Scale bar: 100 μm