Fig. 5

a–f H&E- and g–i Toluidine blue-stained sections from osteochondral plugs. Representative sections from donors #7 and 14 show a an osteochondral plug (CB) after 2 weeks (W2) in culture compared to b CB cocultured with synovium (S), i.e., CBS; c CB after mechanical injury cocultured with S (CBS+INJ). Representative sections from donor #7 show initial matrix depletion in cartilage of CB plugs (d, g). Coculture of osteochondral plugs with synovium (CBS) led to increased disruption of cartilage matrix (e) and further loss of GAG from the exposed sides and surface of cartilage (h). Further matrix disruption, loss of cellularity (f), and GAG (i) were observed in cartilage exposed to injury and coculture with synovium (donor #14) (CBS + INJ). j, k H&E-stained sections of synovium (donor #13) showing cells in synovial lining (2–3 layers) in both fibrous (j) and adipose (k) forms. Please note that d–f are enlargements of a–c. W, week