Interleukin (IL)-4 treatment reduced cartilage destruction,whereas IL-4/prednisolone treatment additionally decreased cell influx.(a) Knee joint from vehicle-treated mouse. Severe cartilage destructioncan be seen. Empty lacunae reflects chondrocyte death as marker of cartilagedestruction, indicated by arrows. (b) Knee joint of a mouse treated withIL-4 1 μg/kg/day for eight consecutive days. Note the reduced cartilagedestruction and chondrocyte death. (c) Knee joint of vehicle-treatedanimal. Note the severe cell influx in synovial tissues and joint cavity.(d) Knee joint of a mouse treated with IL-4/prednisolone (1 μg perday/0.05 mg per kg). Note the marked reduction of cell influx. All specimenswere sampled at day 35. P, patella; F, femur; JS, joint space; C, cartilage; S,synovium. Haematoxylin and eosin staining was used. Original magnifications:× 200 (a, b) and × 100 (c, d).