Antigen-induced arthritis in sdc-3−/−and wild-type mice. Arthritis was induced by intra-articular injection of methylated BSA in the right knee (stifle) joint. For a control, PBS was injected into the left knee joint. (A) Joint swelling after arthritis induction at t = 0, n ≥16 sdc-3+/+and sdc-3−/−mice per time point. Data are means ± SEM for right knee after subtraction of left knee control. ***P <0.001 comparing sdc-3−/−and sdc-3+/+mice at the time points indicated. (B-E) Synovial inflammation and cartilage destruction in mouse antigen-induced arthritis three days after induction. B, wild-type knee joint with marked leukocyte infiltration of the synovium (*), mainly neutrophils. D, wild-type knee joint with loss of proteoglycan staining in the surface regions of tibial and femoral articular cartilage. C and E show sdc-3−/−knee joints and lack of leukocyte infiltration (*) in the synovium and degradation of articular cartilage. B and C were stained with haematoxylin and eosin and D and E with haematoxylin and safranin-O. Scale bar =160 μm in B to E. BSA, bovine serum albumin; PBS phosphate-buffered saline.