Fig. 3

Joint immobilization induces synovial hyperplasia and fibrosis and promotes cartilage lesions in mice. A Representative images of safranin O/fast green (SO/FG) staining (first row) in articular cartilage, Masson staining (second row), two photon imaging for collagenous fiber (third row) and immunohistochemical (IHC) staining of CD31 (fourth row) in synovial tissues of knee joints at 0, 2, 4, and 8 weeks after immobilization. The black arrowheads represent the invading synovium; white dashed lines indicate the synovial tissue. Scale bar, 50 mm. B Synovitis score based on staining results in A. C OARSI score based on staining results in A. D Percentage of type 1 collagen-positive area based on Masson staining results in A. E Percentage of type 1 collagen-positive area based on two-photon results in A. F Percentage of CD31-positive area based on IHC staining results in A. G Results of von Frey test. N = 6 biologically independent replicates per group. Results were expressed as mean ± standard deviation (sd). *P < 0.05, **P < 0.01