Effect of tumor necrosis factor-alpha blocking on bone morphogenetic protein (BMP) expression levels in collagen-induced arthritis. (a) Cumulative severity scores of mice treated with phosphate-buffered saline (PBS) (solid line) or etanercept (dashed line) (n = 9 animals per group). Data are shown as total group scores at each time point. (b) Quantitative polymerase chain reaction of BMP2 (left), BMP7 (middle), and GDF5 (right) on synovium (upper) and cartilage (lower) of mice treated with PBS or etanercept (n = 9 animals per group). Relative expression is normalized to GAPDH. Data are presented as median, quartile, and percentile (Mann-Whitney U test *P < 0.05). (c) Expression of BMP7 on the protein level in articular cartilage from mice treated with PBS or etanercept. Immunohistochemistry for BMP7 on ankle sections. Insets represent higher-magnification views (3:1) of the boxed areas. Bar = 50 μm. GAPDH, glyceraldehydes-3-phosphate dehydrogenase; GDF5, growth and differentiation factor-5.