The profiling and analysis of gene expression in rat temporomandibular joint disc tissue and its derived cells.

OBJECTIVE: The temporomandibular joint (TMJ) disc is composed of a fibrocartilaginous connective tissue. Its dysfunction, resulting from excessive jaw movement, can lead to TMJ disorders. In this study, we aimed to investigate the crucial molecular information regarding the extracellular matrix (ECM), which would be necessary for treating such disorders through TMJ disc regeneration. To achieve this, we compared the gene profiles of TMJ disc tissues, their derived cells, and the periodontal ligament (PDL) in our previous study. METHODS: TMJ discs were isolated from male Wistar rats. Cells derived from the TMJ discs were cultured, and mRNA extracted from the disc tissues and derived cells was analyzed for gene profiling via microarray hybridization. Additionally, we compared the ECM expression between the TMJ disc and the PDL. RESULTS: Collagen (types I, II, III, and VI) and proteoglycans (biglycan and fibromodulin) were highly expressed in the TMJ discs. Significant reduction in decorin, fibromodulin and COL2 were observed in the TMJ-derived cells than in the tissue. Type VI collagen was the third most highly expressed in both the TMJ disc and PDL tissues, following types I and III. CONCLUSIONS: Collagen types VI and II were prominently expressed, followed by collagen types I and III, in TMJ disc tissues, reflecting the unique functions of the disc. Type VI collagen was highly expressed in both TMJ disc and PDL tissues. Overall, type VI collagen might be a key molecule for TMJ disc regeneration, ensuring elasticity and cushioning, and could provide new insights for TMJ regeneration.