Gene and protein expression of brain-derived neurotrophic factor and TrkB in bone and cartilage

Gene and protein expressions of brain-derived neurotrophic factor (BDNF) and TrkB, the high-affinity receptor of BDNF, were investigated in the femur and mandibular condyle of rats by in situ hybridization and immunohistochemistry. BDNF and TrkB mRNA showed overlapped expression in chondrocytes in proliferating and mature zones of the epiphyseal growth plate cartilage and mandibular condylar cartilage, and in cuboidal-shaped active osteoblasts at the site of endochondral and intramembranous ossification and in trabecular bone. Expression of BDNF protein also showed a similar localization. The present study suggests that BDNF may participate in regulating the development and remodeling of bony tissue in the developing rat.