Preventative muMab 911 and cartilage damage or synovitis in the MIA model of OA pain. Histological sections of osteochondral (A–C) or synovial (D–F) tissue. A; PBS-treated saline-injected control showing an intact joint with smooth cartilage, normal joint margin and chondrocyte morphology. B; 1 mg MIA-injected PBS-treated rat showing OA structural pathology: cartilage damage (green arrows); chondrocyte loss (green arrows); subchondral bone changes (asterisk). C: M911-treated MIA-injected rat exhibited similar pathology to the MIA-PBS treated rat (B). D: 1–2 cell deep synovial lining layer (blue arrow) in PBS-treated saline-injected control. E; Synovial hyperplasia (red arrows) in 1 mg MIA-injected PBS-treated rat. F: Synovium from a M911-treated MIA-injected rat exhibited similar pathology to the MIA-PBS treated rat (E). Photomicrographs show haematoxylin and eosin stained sections of knee tissue from a rat with the median pathology score from each group. Scale bars = 200 μm. F = femur, m = meniscus, c = cartilage, t = tibia, sb = subchondral bone and s = synovium.