Fig. 5

(a–d) After surgery, Tg(Δ113p53:GFP) animals were treated with either DMSO (a, a′, c, c′) or DPI (b, b′, d, d′) daily at 3–7 or 7–14 dpa. The treated animals were sampled at 7 and 14 dpa and subjected to cryosection. Cryosections of hearts were immunostained by anti-GFP (in green) and anti-MHC (MF20) (in red) antibodies. The nuclei were stained with DAPI (in blue). Scale bar, 50 μm. e Average size of GFP⁺ cardiomyocytes on heart sections of Tg(Δ113p53:GFP) treated with DMSO or DPI at 7 and 14 dpa, was presented as the percentage of the ventricular area at the resection site. Data are means of three sections/heart. Each dot represents the average size of GFP⁺ cardiomyocytes in an individual heart. Scale bar, 50 μm. f–l Ex vivo HyPer heart images of either Δ113p53^+/+ (f, h, j) or Δ113p53^M/M mutant hearts (g, i, k) at sham, 10.5 and 21 dpa. Spatially resolved H₂O₂ image, indexed by the ratio between the F₄₈₈ and F₄₀₅ images of HyPer (below), is presented in pseudocolor. Ratiometric HyPer signals (F488/F405) averaged over the regenerative zone of injured heart at 3.5, 7, 10.5, 14, 17.5 and 21 dpa were presented as the difference to the average F₄₈₈/F₄₀₅ ratio at the apex of respective sham hearts (l). Each dot represents the ratiometric HyPer signal in an individual heart. Statistical analyses were performed on data from Δ113p53^+/+ and Δ113p53^M/M mutant hearts at the same time point. The experiments were repeated independently for at least three times with similar results. Statistical analysis was performed on relevant data using Student’s two-tailed t test in GraphPad Prism 5. The p values were represented by n.s. and asterisks. n.s., p > 0.05. *p < 0.05. **p < 0.01. ***p < 0.001.