Fig. 1

High-content imaging can detect doxorubicin-induced DNA double-strand breaks in H9c2 cardiomyocytes. A DOX-induced DSB was detected by different methods. B Comet assay results of H9c2 after incubation with DOX for 24 h. Data are plotted as mean ± SD, n = 50 (50 cells). Kruskal–Wallis test was performed, *P < 0.05, **P < 0.01. C Representative images of H9c2 after incubation with 0.5 μM or 5 μM DOX for 1 h or 24 h, γ-H2AX labeled by immunofluorescence. Representative images of cells treated with other different concentrations of DOX were shown in Additional file 1: Fig. S1A. D Intranuclear foci were recognized by the threshold-based traditional image analysis method. E Analysis results of γ-H2AX immunofluorescence images. The number of cells that were captured and quantified was shown in Additional file 1: Fig. S1B. F H9c2 was incubated with DOX for 24 h and the γ-H2AX (Ser139) phosphorylated protein (15 kDa) was detected and GAPDH (36 kDa) was used as the loading control. The quantified results of three experiments were shown in Additional file 2: Fig. S2A. G H9c2 was incubated with different concentrations of DOX for 1 h or 24 h, followed by the immunofluorescence labeling and analysis of 53BP1. The number of cells that were captured and quantified was shown in Additional file 1: Fig. S1C. For E and G, data are plotted as mean ± SD, n = 3, *P < 0.05, **P < 0.01 when compared with the vehicle (dimethyl sulfoxide, DMSO)-treated control group