Figure 5

Protein expression of thrombospondin 1 (THBS1) in (a) rheumatoid arthritis (RA) synovial fibroblast (SFBs) and osteoarthritis SFBs (b), as assessed by immunohistochemistry. Brown staining indicates the presence of THBS1 in SFBs from one representative of three RA and three OA patients; nuclei are counterstained in blue (hematoxylin). The respective staining with an isotype control instead of the specific primary antibody is demonstrated in the insert; the magnification scale is shown in (a).