Previous studies have shown that HA (800 kDa and higher) suppressed IL-1β-stimulated production of collagenases (MMP-1 and MMP-13) by human articular cartilage explants [15] and isolated chondrocytes [38,42], as well as a human chondrosarcoma cell line [53], through down-regulation of phospho-p38 MAPK. Here, MMP1 is linked to chondrosarcoma.