Boundary-lubricating ability and lubricin in synovial fluid of human TMD

Objective: This study was conducted to measure the boundary -lubricating ability and lubricin concentration of synovial fluids (SF) from patients with different stages of temporomandibular joint disorders (TMD) and try to establish relationships between them. Methods: SF samples were obtained from patients with different stages of TMD and healthy volunteers. The boundary-lubricating ability of synovial fluid was determined by the coefficient of friction (COF, μ) of SF in vitro using a friction apparatus. Lubricin concentrations were quantified by enzyme-linked immunosorbent assays (ELISAs). Results: The results suggested that SF with TMD patients represented different COF and the μ values were significantly (P<0.05) higher than those of healthy controls, whereas no observed differences were found between with each other among the groups of DDR, DDNR and OA (P>0.05). The lubricin content level in SF of OA group was higher than that of any other group (P<0.05). However, no significant correlation was found between the COF and the lubricin concentrations in our study. Conclusions: These findings showed that lubricin could be involved in the TMJ boundary lubrication as well as associated with pathological and development of TMD.