DAMPs Synergize with Cytokines or Fibronectin Fragment on Inducing Chondrolysis but Lose Effect When Acting Alone

Figure 1

In the initial two experiments with bovine chondrocytes, HMGB1 synergized with IL-1β on upregulating metalloproteinase production while MTDs (fMLF and CpG DNA) or HMGB1 alone showed little effect. Cells were harvested from cartilage in bovine stifle joints and cultured for 1 week. Passage 1 cells were treated with MTDs, HMGB1, and/or IL-1β. After 24 hrs, culture medium was collected, dialyzed, and concentrated. The expression of MMPs in each medium sample was determined with Western blotting. U. C. = untreated control; CpG = CpG-rich DNA; CpG N. C. = CpG-rich DNA negative control.