Fig. 2: Imperatorin promotes cardiomyocyte proliferation after apical resection.

A Schematic diagram of the experimental design for imperatorin treatment in P1 neonates. B Hematoxylin-eosin staining showing the anatomical structure after imperatorin treatment at P7. Scale bar, 1 mm. C Heart weight to body weight ratios of hearts after imperatorin treatment at P7. N = 6 mice/group. D Heart weight to tibia length ratios of hearts after imperatorin treatment at P7. N = 6 mice/group. E Cardiac function in P7 mice after imperatorin treatment was measured by ejection fraction (EF%). N = 10 mice/group. F Wheat germ agglutinin (WGA) staining and quantification of cardiomyocyte size of hearts after imperatorin treatment at P7. Scale bar, 40 µm. N = 5 mice/group. G Representative images and quantification of Ki67⁺ cardiomyocytes of hearts after imperatorin treatment at P7. Scale bar, 40 µm. N = 10 mice/group. H Representative images and quantification of pH3⁺ cardiomyocytes of hearts after imperatorin treatment at P7. Scale bar, 40 µm. N = 10 mice/group. I AR was performed on P8 mice, and hearts were harvested at 7 and 21 days post-resection. J Representative images and weights of resected apexes at P8. Scale bar, 1 mm. N = 10-12 mice/group. K Cardiac function in P29 mice after imperatorin treatment was measured by EF% and fraction shortening (FS%). N = 10 mice/group. *p < 0.05 vs. Control. L Representative images and quantification of scar size after imperatorin treatment at P29. Scale bar, 160 µm. N = 8 mice/group. *p < 0.05 vs. Control. M WGA staining and quantification of cardiomyocyte size of hearts after imperatorin treatment at P15. Scale bar, 40 µm. N = 5-8 mice/group. *p < 0.05 vs. Control. N Representative images and quantification of Ki67⁺ cardiomyocytes of hearts after imperatorin treatment at P15. Scale bar, 40 µm. N = 5-8 mice/group. *p < 0.05 vs. Control. O Representative images and quantification of pH3⁺ cardiomyocytes of hearts after imperatorin treatment at P15. Scale bar, 40 µm. N = 5-8 mice/group. *p < 0.05 vs. Control. P Representative images and quantification of γH2AX foci in cardiomyocytes after imperatorin treatment at P15. Scale bar, 40 µm. N = 6-7 mice/group. *p < 0.05 vs. Control. Q Representative images and quantification of p-ATM foci in cardiomyocytes after imperatorin treatment at P15. Scale bar, 40 µm. N = 6-7 mice/group. *p < 0.05 vs. Control.