Augmented Bone Morphogenetic Protein Signaling During TMJ Development Alters Morphology in a Timepoint-Dependent Manner.

The temporomandibular joint (TMJ) is unique in both developmental origin and functional maintenance. The role of bone morphogenic protein (BMP) signaling in endochondral ossification has been widely investigated but not in the context of the TMJ. We employed a histomorphometric analysis approach to understand how augmented BMP signaling in the cranial neural crest affects the postnatal development of the TMJ. Our analysis showed that cartilage length in the mandibular condyle was reduced in Wnt1 Cre;caBmpr1a mice before the weaning stage (P17). However, following weaning, the mandibular condylar cartilage showed recovered length (P28 and P42). Furthermore, the changes in cartilage length coincide with alterations in cell death in the superficial region of the mandibular condyle. These results suggest that BMP signaling influences chondrocyte cell death and TMJ development in a timepoint-specific manner.