The flow cytometry data were subjected to a Mann–Whitney rank sum test (SigmaStat,

version 3.10, Systat Software, Inc., Chicago, IL). The data were considered statistically different if p < 0.05. The data for GFP and αSMA were tested with a paired two-tailed Student's t-test, and a normal Student's t-test for differences between the wound tissue in skin and in mucoperiosteum. The data from the adjacent tissue in skin and mucoperiosteum were tested similarly. If the data were not normally distributed, a Wilcoxon signed rank test was performed for paired data, and a Mann–Whitney rank sum test for independent data. The HSP47 and CD68 data were only tested for differences between the wound tissue and the adjacent tissue in skin. The data were considered statistically significant when p < 0.025. The fraction of GFP-positive mononuclear cells in the blood of the donor rats and the transplanted rats was not significantly BIBW2992 different (86 ± 2% and 69 ± 9% respectively, Fig. 1). This indicates a good take of the bone marrow graft. The histology of the mucoperiosteum Alpelisib and skin is shown in Fig.

2A. Both tissues have a keratinized epithelium overlaying the lamina propria (mucoperiosteum) and dermis (skin). The mucoperiosteal epithelium contains more cell layers than the epidermis. Skin dermis also contains hair follicles with the arrector pili muscles and sebaceous glands. Underneath the dermis lies the hypodermis with fat cells. Both types of wounds have a high cell density. In the skin wounds, no regenerated hair follicles are present, and the hypodermis is lost. Further, Fig. 2 shows representative examples of the immunostainings. In the wounded mucoperiosteum, more GFP-positive cells are present than in the adjacent tissue (Fig. 2B). In skin, the numbers in wounded and adjacent tissue are similar. Few GFP-positive cells were detected in the epithelia or in the hair follicles of the unwounded skin. In the mucoperiosteal

wounds, high numbers of myofibroblasts were present, whereas far less were present not in the skin wounds (Fig. 2C). Only few of these were also GFP-positive. No myofibroblasts were detected in the adjacent tissues of the mucoperiosteum and the skin. Activated fibroblasts (HSP47-positive cells) were present in the wounds and adjacent tissues of both the mucoperiosteum and the skin (Fig. 2D). Activated fibroblasts were brightly stained in the wounds, whilst they were stained less intensely in the adjacent tissues. Only few of the activated fibroblasts were also GFP-positive. The number of macrophages was similar in the wounds and the adjacent tissues of the mucoperiosteum and the skin (Fig. 2E). A relatively large number of these cells were also GFP-positive. Fig. 3 shows the quantitative data of the immunostainings. The total fraction of GFP-positive cells (Fig. 3A) in the mucoperiosteal wounds (8.1 ± 5.1%) was significantly larger than in the adjacent tissue (0.7 ± 0.8%, p = 0.025).