Fig. 4

Echocardiographic measurement and ex vivo gross observation confirm regeneration of the X. tropicalis injured heart in a scar-free manner. A and B: The diastole end ventricular length and the diastole end ventricular area of the injured heart group in the 5-daar group were significantly shorter than those of the same-age nonapical resection control group. The differences in the diastole end ventricular length and diastole end ventricular area of the injured heart group in the 45-daar group compared with the same-age nonapical resection control group were not statistically significant. C and D: The diastole end ventricular length and the diastole end ventricular area of the injured heart group were increased in the 10-daar, 30-daar and 45-daar hearts. At 30 daar, they were close to the same-age nonapical resection control group, while at 45 daar, the diastole end ventricular length and the diastole end ventricular area of the injured heart group were nearly the same compared with the same-age nonapical resection control group. E: The ejection fraction (EF) of the injured heart group at 5 daar was decreased significantly compared with the same-age nonapical resection control group. The difference in EF between the injured heart group and the same-age nonapical resection control group at 45 daar was not statistically significant. F: The EF of the injured heart was increased at 10 daar, 30 daar and 45 daar. At 30 daar, it was close to the same-age nonapical resection control group, while at 45 daar, the EF of the injured heart group was nearly the same compared with the same-age nonapical resection control group. G: Ex vivo gross observation of the regenerated X. tropicalis heart at 45 daar, in which echocardiography observation showed that the injured heart was regenerated with no adhesion and was scar-free. G-g1: Representative image of the regenerated X. tropicalis heart at 45 daar after in vivo exposure. G-g2: The front side image of the isolated regenerated heart of G-g1. G-g3: Image of the dorsal side of the isolated regenerated heart of G-g1. G-g4: Apical side image of the isolated regenerated heart of G-g1. Ex vivo gross observation confirmed that the cut apex was regenerated with nearly normal morphology, in which the boundary between the apical region of the regenerated heart and the surrounding tissue was clear, and no adhesion with the surrounding tissue was found. 5 daar: 5 days after apical resection