Fig. 2

Synovial changes in WT and M3R-deficient mice with CAIA. a–g Hematoxylin and eosin (H&E) staining of knee joint sections from male WT-LPS (a), M3R^−/−-LPS (b, e), WT-CAIA (c, f) and M3R^−/−-CAIA (d, g) mice. Original magnification: 25× (a–d) and 200× (e–g). h Quantification of histopathological changes in knee joint synovial tissue of male arthritic WT and M3R^−/− mice. Data are given as mean histopathological score ± SEM. i–p Transmission electron microscopy of synovial macrophages (i–l) and fibroblasts (m–n) of male WT-LPS (i and m), M3R^−/−-LPS (j and n), WT-CAIA (k and o) and M3R^−/−-CAIA (l and p) mice. Original magnification: 5000×. CAIA collagen antibody-induced arthritis, LPS lipopolysaccharide, M3R M3 muscarinic acetylcholine receptor, WT wild-type