Fig. 5 | Nature Communications

Fig. 5

From: Periosteum contains skeletal stem cells with high bone regenerative potential controlled by Periostin

Fig. 5The alternative text for this image may have been generated using AI.

Periostin is required for adequate bone repair. a qRT-PCR analyses of PCs and BMSCs isolated from un-injured tibias and tibias 3 days post-injury. Periostin (Postn) is specifically upregulated in PCs in response to injury and in PCs compared to BMSCs in response to injury. b SO staining and DAPI/POSTN immunofluorescence on wild-type longitudinal tibia sections showing Periostin (POSTN) expressing cells in the un-injured periosteum near the cortex (immunofluorescence corresponds to box area in SO). qRT-PCR analyses show high Postn expression in Prx1-derived PCs (GFP+) sorted from PCs cultures of un-injured hindlimbs of Prx1-Cre;mTmG mice. Three days after fracture, POSTN is highly expressed in the cambial layer (cl) of the activated periosteum (GFP) coinciding with expression of CD29 (Red). At day 14 post-fracture, POSTN is expressed in hypertrophic cartilage at the junction between cartilage and bone within the callus (box 1, GFP) and in osteoblasts within new bone trabeculae (box 2, white arrows). By day 28, POSTN expression is high in the inner layer of the newly formed periosteum at the periphery of the remodeling callus. Scale bar: 0.5 mm. c Histomorphometric analyses of callus, cartilage, and bone volumes at days 7 (d7), 10 (d10), 14 (d14), 21 (d21), and 28 (d28) post fracture in wild type (WT) and Periostin KO (KO) mice. d Picrosirius red staining (PS) on longitudinal sections of fracture callus at d28 shows absence of consolidation and fibrosis in Periostin KO mice (black arrows). Scale bar: 1 mm. SO: Safranin-O/Fast Green, TC: Masson’s trichrome, m: muscle, c: cortex, po: periosteum, fl: fibrous layer, cl: cambial layer, b: bone, bm: bone marrow, ca: cartilage, f: fibrosis, CTL: non-immune IgG. Black dashed line: cortex (un-injured and day 3) or callus (day 14). White dashed line: periosteum (un-injured and day 3) or bone trabeculae (days 14 and 28). Statistical differences between the groups were determined using Mann–Whitney test (*p ≤ 0.05, **p < 0.001, ***p < 0.0005) (n = 3–5). All data represent mean ± SD

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