Fig. 5: FoxO3 knockout improves heart regeneration following MI injury at non-regenerative stage.

a Schematic of sample collection and analysis at indicated time points after MI surgery at p8. b, d Representative images (b) and quantification (d) of Ki67⁺ cardiomyocytes in the border zone of infarcted hearts at 7 dpM (n = 3 hearts). c, e Representative images (c) and quantification (e) of pH3⁺ cardiomyocytes in the border zone of infarcted hearts at 7 dpM (n = 3 hearts). f, g Representative images (left) and quantification (right) of symmetrical (f) and asymmetrical (g) AurkB⁺ cardiomyocytes in the border zone of infarcted hearts at 7 dpM (n = 5 hearts). h, i Representative images of M-model echocardiography (left) and quantification (right) of LVEF and LVFS levels in control and CKO mice at 14 (h) and 28 (i) dpM (n = 6 mice for Con and 7 mice for CKO). j Representative Masson’s trichrome staining images (left) and quantification of scar size (right) at 28 dpM (n = 6 mice). k Schematic of sample collection and analysis at indicated time points after MI surgery in adult iCKO mice. l Validation of the inducible knockout of FoxO3 in heart tissues. m, n Representative images (left) and quantification (right) of Ki67⁺ (m) and pH3⁺ (n) cardiomyocytes in the border zone of infarcted hearts in iCKO mice at 7 dpM (n = 5 hearts). o Representative WGA staining images (left) and quantification (right) of cardiomyocyte size in the border zone of infarcted hearts at 7 dpM (n = 10 mice). p Quantification of LVEF and LVFS levels in control and iCKO mice from 0 to 28 dpM (n = 10 mice). Control mice without MI injury were used as sham group (n = 6 mice). q Representative images of M-model echocardiography in control and iCKO mice at 28 (P) dpM. r Representative Masson’s trichrome staining images (left) and quantification of scar size (right) in control and iCKO mice at 28 dpM (n = 10 mice). All data are presented as the mean ± SEM. P values are from two-tailed t test (d–j, m, n, r), one-way ANOVA followed by Tukey’s multiple comparisons test (o), or two-way ANOVA followed by Sidak’s multiple comparisons test (p). Source data are provided as a Source Data file.