T-Lymphocytes Enable Osteoblast Maturation via IL-17F during the Early Phase of Fracture Repair
Figure 4
Osteogenesis is reduced in Rag1
−/− mice during fracture repair. (A) In vitro cultures of primary mesenchymal stromal cells differentiated to osteoblast colony-forming units (CFU) showed lower gene expression levels of bone markers Col1, Col2 and BSP and osteocalcin in Rag1−/− mice compared to WT. *p<0.05, **p<0.01 (n = 10). (B) Alizarin red staining of osteoblast CFU showed significant decrease in mineralization at 20 days of culture in Rag1−/− compared to WT. CFU-osteoblast was quantified by direct counting of all stained nodules positive to Alizarin Red using light microscopy. (C) Digital fluorescent microscopy images of calcein green administered mice 2 and 9 days prior to harvest at 21 and 28 days post fracture exhibited a smaller distance measured between mineralization fronts and hence, less bone formation in Rag1−/− compared to WT mice (p<0.05). Unfractured limbs showed no significant differences in bone formation.