To examine the role of matrix metalloproteinases(MMP) expressed by the tartrate-resistant acid phosphatase (TRAP)-positive mononuclear and multinucleated cells in articular cartilage damage.
C57BL/6 mice were immunized by injection of chicken type II(CII) collagen to construct the collagen-induced rheumatoid arthritis(CIA) model. The presence of TRAP positive cells in the synovial tissue of CIA mice was examined by enzyme histochemistry and expression of MMP-2,9 was assessed in TRAP positive cells by immunohistochemistry.
Expression of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) was detected in TRAP positive mononuclear and multinucleated cell. Quantity of TRAP positive cells and the destruction of articular cartilage had a positive correlation (r(s) =0.903, P<0.01). Expression of MMP-2 and MMP-9 in TRAP positive cells was also correlated significantly with the destruction of articular cartilage (r(s) =0.954, P<0.01).
This study suggests that MMP-2 and MMP-9 expression by TRAP positive mononuclear and multinucleated cells are involved in articular cartilage destruction in CIA.