Gli1⁺ Cells Residing in Bone Sutures Respond to Mechanical Force via IP₃R to Mediate Osteogenesis

Figure 1

Gli1⁺ cells residing in palatal sutures involved in mechanical force-induced maxillofacial bone remodeling. (a) Experimental procedure: Gli1-LacZ mice were sacrificed seven days after rapid maxillary expansion (RME) treatment. Control mice were not subjected to RME and were sacrificed at the same time. (b) Coronal sections of maxillae of RME and control mice were stained with hematoxylin/eosin and Masson’s staining. Compared with that in the controls, maxillofacial sutures in RME mice were expanded, and cells residing on the nasal and oral sides of the suture had increased. Collagen in the suture was rearranged along the direction of the mechanical force. The area between two dotted lines shows the midpalatal suture. Scale bar: 100 μm; . (c) New bone formation was visualized using calcein; the distance between green fluorescence lines indicates newly formed bone. Scale bar: 20 μm; . (d) New bone deposition rate was faster in the RME group, ; . (e) Micro-computed tomography (micro-CT) shows horizontal plane views of the maxillae. Scale bar: 2 mm. The left panel shows magnified sutures in the boxes. Scale bar: 0.5 mm. (f) The distance between two first molars was widen in RME mice. ; . (g) Immunofluorescence staining presents Gli1 (green) and RUNX2 (red) expression in the midpalatal suture areas of the RME group and control group. Scale bar: 100 μm. Regions in boxes are magnified in the right panel: “N” indicates the nasal side of the midpalatal suture and “O” indicates the oral side. Scale bar: 50 μm. (h) Proportions of Gli1⁺ cells increased on nasal and oral sides and midpalatal suture in RME mice. ; . (i) Proportion of RUNX2⁺ cells in midpalatal suture increased in RME mice. ; . (j) Gli1⁺ and RUNX2⁺ cells increased in sutures of RME mice. ; .

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