Statistical analysis
The in vitro experimental data are expressed as the mean ± standard error of the mean of quadruplicate samples. Differences between groups were assessed by repeated analysis of variance followed by the Dunnett multiple comparison test. The level of MMPs, VEGF, and adiponectin in the joint fluid of RA and OA patients was compared between groups with the unpaired t test. To determine the degree of linearity between two variables, data were compared using the Pearson correlation test (two-tailed). Prism software 4 (GraphPad Software, Inc., San Diego, CA, USA) was used for statistical analysis and graphing. Differences were considered significant at a P value of less than 0.05.