| ObjectiveTo detect Wnt-1 protein andβ-catenin in temporomandibular joint developmental process of human embryos; and to clarify the role of canonical Wnt signaling pathway in condylar chondrogenesis.Materials and methodTemporomandibular joints were obtained at autopsy in four human fetuses that had no congenital anomalies. The subjects ranged from 3 to 6 months of gestational age.The expressions features of Wnt-1 protein andβ-catenin in temporomandibular joint cartilage were examined during normal prenatal growth using an immunohistochemical method.ResultsAccumulation of Wnt-1 andβ-catenin in cartilage of condyle and disc was immunohistochemically proven in 4 cases of human embryos.On sections at month 3, we detected an extensive expression of Wnt-1 in most of all layers of cartilage of the condyle and disc. Compared with the perichondrium and the immature chondrocytes, the chondrocytes within proliferation zone had been less immunohistochemically stained, as well as the mature osteocytes. Wnt-1 expression in hypertrophy zone and calcified zone on sections at month 6 was weaker than that of month 3.A stronger and more extensive expression ofβ-catenin was detected in temporomandibular joint cartilage than that of Wnt-1. The amount of stained-positive cells within fibrous structure and superficial layer seemed a little bit high than deep layers. In contrast with Wnt-1,β-catenin expression increased from sections at month 3 to month 6.It might be noticed that on whichever sections, both expressions of the two proteins were found in temporomandibular joint surrounding matrix and the connected tissue. ConclusionWnt-1 was expressed in fibrocartilage and immature chondrocytes in temporomandibular joint.β-catenin was expressed in chondrocytes and osteoblasts extensively in temporomandibular joint. That may be draw a conclusion that Wnt-1 is associated with chondrocytes differentiation, andβ-catenin is related with all stages of temporomandibular joint development. |
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