Clinical and histological evaluation of arthritis. Clinical and histological evaluation demonstrates that arthritis induced with 200 μg glucose-6-phosphate isomerase (G6PI) in complete Freund's adjuvant (CFA) leads to chronic destructive arthritis in mice on the C3H background. (a) Healthy C3H.Q hind foot. (b) A C3H.Q hind foot 90 days after disease induction. The digits are still red and swollen. After day 90 paws were fixated and decalcified for paraffin sectioning. Histopathology demonstrates the destructive character of the GPI-induced arthritis in C3H in comparison with DBA/1 mice. Both mice achieved clinical scores in their hind feet of 15. The C3H mouse developed (e) an irreversible destruction of their joints through invasive pannus tissue accompanied by new bone formation, (j) destroying the whole architecture of the ankle, whereas DBA/1 mice have relatively intact joints, apart from (d) smaller erosions (arrows) and (i) hyperplasia. (c,h) Healthy control joints. The severity of the disease on the C3H background is also indicated by (g) the destruction of intervertebral structures such as the annulus fibrosus, nucleus pulposus and the vertebra themselves by inflammatory cells (arrow). (f) Healthy control tail. Staining with haematoxylin and erythrosine; original magnification 25× and 100×. af, annulus fibrosus; np, nucleus pulposus; o, osteophytes; pa, pannus; sy, synovial membrane; ta, talus; ti, tibia.