(A) Periostin protein expression in early wound healing. Wounds at day 1(a, d), 2(b, e), and 3(c, f) after wounding were stained with anti-periostin antibodies. Figures d, e, and f show a high magnification of “a,” “b,” and “c,” respectively. At day 1, periostin protein was expressed mainly in hair follicles (d, arrow) and weakly at the basement membrane in the hair follicle opening area (d, arrowhead). At days 2 and 3, the protein was localized more clearly at the basement membrane of the epidermis (b, c; arrow) and diffusely around the hair follicle (e, f; arrowhead). Red arrowheads indicate the wound edge. Scale bar: 100 µm (a, b), 50 µm (c, d); sc: scab. (B) H&E staining (a–d) and periostin protein expression in wounded skin assessed by immunohistochemistry (e–h) at 3, 5, 7, and 10 after wounding. Periostin was localized in granulation tissues. The dotted line in each photo indicates the border between the dermis and the granulation tissue. Scale bar: 100 µm; gt: granulation tissue (C) Periostin mRNA in situ hybridization of skin at 5 days after wounding. The sections were probed with the anti-sense cRNA probe (a) and the control sense probe (b). The periostin-positive area in “a” is magnified in “c and “d”: periostin-positive fibroblasts surrounding a hair follicle (arrowhead in “c”) and at the border of the wound area (arrow in “d”) are seen. The signals were not detected with the sense probe (b). Scale bar: 100 µm (a, b), 50 µm (c, d).