The aim of this study was to evaluate a subset of matrix metalloproteinases (MMPs) and proinflammatory cytokines within the synovium, from traumatic knee disorders (TKDs) and nontraumatic osteoarthritis (OA).
MMP-1, MMP-3, interleukin 1beta, and tumor necrosis factor (TNF) alpha gene expression was quantified by use of TaqMan-based real-time polymerase chain reaction (Applied Biosystems, Foster City, CA) in synovial tissue samples obtained from 12 patients with OA and 32 with TKDs. In addition, the levels of serum inflammatory parameter C-reactive protein (CRP) were recorded. At arthroscopy, the amount of chondral damage was graded based on the Outerbridge classification.
Quantitative analysis showed no significant differences in the expression levels of MMPs, interleukin 1beta, or TNF-alpha messenger RNA between the synovial tissues of patients with OA and TKD, but CRP level was significantly increased in the OA group. A significant correlation was also seen regarding the gene expression levels between MMP-1 and -3, as well as between CRP and MMPs tested. Furthermore, significant relations between TNF-alpha and MMP-1 plus MMP-3 were observed in the OA synovial tissue. The level of TNF-alpha in the synovial tissue correlated with the time after injury as well as chondral damage in patients with TKD.
TNF-alpha could provide a factor to quantify individual risk for the development of OA.
This study shows similar changes in the inflammatory patterns of synovial tissue of TKD and OA suggesting a likely disease progression. Moreover, the correlation between CRP and MMP expression levels indicates their essential role in joint degeneration in synovial tissue of primary OA patients.