Fig. 3: The absence of wound contraction has been reported in several cases of spontaneous scarless healing in various species.

a No αSMA⁺ fibroblasts (red) were detected 12 days after full-thickness ear injury in A. kempi, which are able to spontaneously regenerate severe skin injuries. b In contrast, a significant number of αSMA⁺ cells (red) were detected in ear injuries in Mus musculus mice, which spontaneously heal such injuries by forming a scar³⁵. c, d The axolotl can regenerate spontaneously injuries in several organs, including its limbs and tail. c αSMA staining was not detected in skin injuries, 12 days after injury. d In the same animal, αSMA (brown) was detected in control tissue (small intestine)^37,38,39. Figure 3a, b were reproduced with permission from Nature 489, 561–66, ^©Springer Nature (2012). Figure 3c, d was reproduced with permission from J. Exp. Zool. B. Mol. Dev. Evol., 314B, 684–97, ^©Wiley (2010).