Expression of Transcription Factor Sox9 in Cartilage Formation from Grafted Periosteal Cells

Objective: To investigate the expression of Sox9 protein in the process of cartilage formation after periosteal grafting using the rat periosteum graft model.Materials and Methods: Periostea taken from twenty 7-week-old rats were immediately grafted into the suprahyoid muscles. Grafted tissues were harvested 0, 7, 14, and 21 days after grafting and examined by microscopy and immunohistochemistry using CD44, type 2 collagen, and Sox9 antibodies as markers.Results: Periosteal cells expressed CD44 after 7 days and Sox9 after 14 days. The Sox9-positive cells showed chondrogenic differentiation with type 2 collagen expression by 21 days after grafting. Endochondral ossification was also seen 21 days after grafting. Sox9 was not detected in hypertrophic chondrocytes.Conclusion: These findings suggested that Sox9 may be related to chondrogenic differentiation of periosteal cells in grafted periosteum.