Figure 3.

Zymographic analysis of MMP-2 and MMP-9 levels in arthritic synovial fluids. (a) Secretion of MMP-2 and MMP-9 was assessed by gelatin zymography using standard procedures. Aliquots of 10 μl synovial fluids (SF) (diluted 1:10) were loaded into each lane. OA, osteoarthritis; snPA, seronegative polyarthritis; rPA, seropositive rheumatoid polyarthritis; CPDD, calcium phosphate deposition disease; SpA, spondyloarthropathy; PA, polyarthritis; JCA, juvenile chronic arthritis; MA, microcrystalline arthritis. (b) Semiquantitative measures of the proMMP-9 level were carried out by densitometric analysis (scored as arbitrary units) and compared with the net proteolytic activity (NPA) found in the same SF. No correlations between the NPA and the level of the 225 kDa form of MMP-9 or with that of its active form (92 kDa) were observed (data not shown). FASC, fluorescent-activated substrate conversion. As a positive control, an aliquot of supernatant of HT1080 cell culture containing both MMP2 and MMP-9 gelatinases was used. The results were obtained using duplicates and are representative of two independent experiments. Error bars represent the mean ± standard error of the mean.