Expression of matrix metalloproteinase-2 and-9 in synovial fluid of the temporomandibular joint accompanied by anterior disc displacement

The purpose of this study was to determine whether or not matrix metallopro teinases (MMPs) in synovial fluid are helpful in the biochemical diagnosis of temporomandibular joint (TMJ) disorder (TMD). We examined the synovial f luid from 38 TMD patients with disc displacement and 20 volunteers by gelat in zymography and immunoblotting analysis to clarify the involvement of the joint pathology from the viewpoint of expression of MMPs. Two gelatinolyti c enzymes, MMP-2 and -9, were detected in the samples. The incidences of ex pression, except for pro-MMP-2, in anterior disc displacement (ADD) without reduction (ADD w/o R) were significantly higher than in ADD with reduction (ADD w R) (P<0.05). Quantitative analysis showed that the degree of MMP-2 and -9 expression in ADD w/o R were higher than in ADD w R. These data sugg est that the presence or absence of disc reduction is a major turning point in the process of joint destruction, and these MMPs are useful as biochemi cal markers for TMD diagnosis.