Fig. 1

Collagen triple helix repeat containing 1 (CTHRC1) expression is inducible in arthritis. Histology of hind limb (a, b) and knee joint (c–f) sections of naïve and arthritic BALB/c mice. Ti tibia, Ta talus, N navicular bone of hind paw. In naïve mice, synovial membrane is normal (a, c, green arrowheads). In mice with experimentally induced arthritis at the seventh day post injection of anti-collagen antibodies, massive multicellular pannus (yellow arrowhead) and influx of granulocytes into synovial cavity (blue arrowhead) were prominent (b, d). Immunohistochemical staining for CTHRC1 was negative in the normal synovial membrane (e) in contrast to strong positive staining of the arthritic hyperplastic synovium (f, brown 3,3′-diaminobenzidine precipitate). The border between bone (Bn) and cartilage (Ct) is shown with a dashed line (f). Sections were counterstained with hematoxylin (e, f) or stained with hematoxylin-eosin (a–d). Scale bars are 100 μm (a, b) and 50 μm (c–f). The data and images are representative of the two independent experiments using BALB/c wildtype inbred mice and mice from (FVB/J × BALB/c)F1 hybrid genetic backgrounds