Time course of wound closure promoted by Activin B.

<p>Forty four mice were randomly assigned to PBS group and Act B group (n = 22). (A) Activin B promoted wound closure in KM mice as compared with control. KM mice received 0.2 ml of PBS or Activin B treatment three times per day. The wound healing status was monitored every day. (B) The wound closure rate was calculated as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0025143#s4" target="_blank">Materials and Methods</a>. *<i>P</i><0.01compared with PBS control. (C) H&E staining of the skin tissues surrounding wound sites. Scale bar: 100 µm. (D) SEM analysis showed that activin B induced cell proliferation on the surface (black star) and cross-section (black arrows) of wound area. Re-epithelized squamous epithelium is indicated by black arrowheads. (E) TEM analysis demonstrated that Activin B reduced cell-cell contacts and increased intercellular spaces (arrows) at wound area (b) compared with control (a). (c) The hair follicle seen in the regenerated skin after activin B treatment. Ea, Eb, Scale bar: 2 µm; Ec, Scale bar: 5 µm.