Fig. 5

ISL inhibits DNA damage and attenuates doxorubicin-induced cardiotoxicity in H9c2 cardiomyocytes. A Dose-dependent influence of ISL on foci formation in EGFP-53BP1-H9c2 treated with 0.5 μM DOX for 1 h. B Effect of ISL on the level of phosphorylated γ-H2AX (Ser139) protein (15 kDa). C Effect of ISL on the level of DSB detected by the comet assay. D Effect of ISL on the proportion of apoptotic/necrotic cells, which were labeled with annexin V-FITC. E Effect of ISL on the protein levels of BAX (21 kDa) and Caspase 3 (35 kDa). F Effect of ISL on the cellular peroxynitrite labeled with B545b. G Effect of ISL on the level of HO-1 protein (28 kDa). H Effect of ISL on the level of topo II protein (180 kDa). The lower band with lower molecular weight was topo IIα, and the upper band with larger molecular weight was topo IIβ. For (B) ~ (G), H9c2 was incubated with 0.5 μM DOX and certain concentrations of ISL for 24 h. For (H), H9c2 was incubated with 0.5 μM DOX and certain concentrations of ISL for 1 h. For (B), (D), and (F), data are plotted as mean ± SD, n = 3, and data were analyzed by ANOVA. For (C), data are plotted as mean ± SD, n = 62, and data were analyzed by Kruskal–Wallis test. ^#P < 0.05, ^##P < 0.01 when compared with the control group; *P < 0.05, **P < 0.01 when compared with the DOX group. I Molecular docking results of ISL to topo II. Salt bridge: purple line; hydrogen bond: yellow line; cation-π: green line. The quantified results of western blotting in (E), (G) and (H) were shown in Additional file 2: Fig. S2B–E