Fig. 2.

α-SMA expression is reduced in the granulation tissue of Postn^−/− mice. (A) Postn message detection in day 7 Postn^+/+ wounds by in situ hybridization, showing periostin expression selectively in the wound. Arrowheads indicate the wound borders. (B) Histological analysis of day 7 wounds from Postn^+/+ (WT) and Postn^−/− (KO) animals. Sections were incubated with antibodies against periostin or α-SMA. Detection was with peroxidase-conjugated secondary antibodies and DAB. Day 7 Postn^−/− wounds have reduced α-SMA staining (n=5). (C) Healthy skin or wound tissue biopsies were analyzed for Postn and (D) Acta2 mRNA by RT-qPCR. Target gene expression was normalized to 18S using the ΔΔCt method. Postn expression is significantly increased at day 7 (P<0.001, n=5). Postn mRNA was not detected in Postn^−/− specimens. Increased Acta2 expression was observed at day 7 in Postn^+/+ wounds, but not in Postn^−/− wounds (P<0.001, n=5). Data are expressed relative to day 0 Postn^+/+ expression; error bars represent s.e.m. (*P<0.001; two-way ANOVA).