Figure 1

Induction of arthritis in SKG mice. (a to f) Images of the hind and fore limbs (a) control Balb/c mice (no inflammation); (b) Balb/c mice+Zymosan (no inflammation); (c) SKG mice (no inflammation); (d) SKG mice + Zymosan A (moderate inflammation); (e) SKG mice +Zymosan A + TUBO (moderate inflammation); (f) SKG mice + Zymosan A + 4T1 cells (severe inflammation). (g) Scoring of joint swelling: Compared with SKG mice + Zymosan A or SKG mice +Zymosan A + TUBO, a significant increase in joint swelling was observed in SKG mice injected with Zymosan A and challenged with 4T1 cells (P < 0.05). (h to n) H&E staining of sections from the joints: (h) Balb/c mice; (i) SKG mice; (j) SKG mice + Zymosan A without tumor challenge (moderate inflammation); (k) SKG mice + TUBO cells; (l) SKG mice + Zymosan A + TUBO cells showing some erosion of articular cartilage; (m) SKG mice + 4T1 cells showing severe inflammation in the phalangeal joints; (n) SKG mice + Zymosan A + 4T1 cells showing severe synovial hyperplasia and erosion of articular cartilage and bone in phalangeal joints with severe inflammation; (o to t) Masson trichome staining of sections from the bones: (o) Balb/c mice; (p) Balb/c mice + Zymosan A; (q) Balb/c mice +Zymosan A + 4T1; (r) SKG mice; (s) SKG mice + Zymosan A (arrow represents osteoclast); (t) SKG + Zymosan A + 4T1 (multiple osteoclasts marked with arrows). The H&E images of the joints were taken at 200 × magnification and the Masson Trichome bone images taken at 400 × magnification.