Fig. 7

Stronger effect of CAIA on bone destruction in M3R-deficient mice. a–d Toluidine blue staining on sections from knee joints of male WT-LPS (a), M3R^−/−-LPS (b), WT-CAIA (c), and M3R^−/−-CAIA (d) mice. Original magnification: 200×. e Histopathological quantification of bone destruction in knee joints of male arthritic WT and M3R^−/− mice. Data are given as mean of histopathological score ± SEM. ^# P < 0.05: M3R^−/−-CAIA vs. WT-CAIA. f–h Toluidine blue staining (f) and immunohistochemistry for tartrate-resistant acidic phosphatase (TRAP) (g and h) on section from knee joint of representative male M3R^−/−-CAIA mouse. Original magnification: 200× (f, g) and 1000× (h) The square in g indicates the area shown in h. i–l Transmission electron microscopy of osteocytes in knee joints of male WT-LPS (i), M3R^−/−-LPS (j), WT-CAIA (k) and M3R^−/−-CAIA (l) mice. Original magnification: 6300×. CAIA collagen antibody-induced arthritis, LPS lipopolysaccharide, M3R M3 muscarinic acetylcholine receptor, WT wild-type