The Zonal Architecture of the Mandibular Condyle Requires ADAMTS5

Immunohistochemistry and Western blots demonstrated the expanded ECM correlated with increased Acan localization in Adamts5 –/– compared to Adamts5 +/+ . Cell volume was also decreased in the MCC of Adamts5 –/– due to both a reduction in cell size and less mature hypertrophic chondrocytes. Analysis of chondrogenic maturation markers by quantitative real-time polymerase chain reaction indicated Col2a1 , Col10a1 , and Sox9 were significantly reduced in Adamts5 –/– MCC compared to that of Adamts5 +/+ .

The older (6 mo) Adamts5 –/– MCC exhibited changes in chondrogenic cell arrangements, including clustering and chondrogenic atrophy, that correlated with early stages of TMJOA using modified Mankin scoring. These data indicate a potentially novel and critical role of ADAMTS5 for maturation of hypertrophic chondrocytes and establishment of the zonal architecture that, when disrupted, may lead to early onset of TMJOA.