Fig. 8

Analysis of markers for joint destruction in arthritic WT and M3R^−/− mice. Real-time reverse transcription polymerase chain reaction (RT-PCR) analysis of Mmp13 (a), Rankl (e), and Ctsk (i) mRNA expression in paws of male WT and M3R^−/− mice with CAIA and respective LPS-treated control mice, normalized to β- actin mRNA. *P < 0.05 and **P < 0.01 CAIA vs. respective LPS control. Correlation of Mmp13 (b), Rankl (f) and Ctsk (j) mRNA expression with the arthritis score of the respective paw in male arthritic WT and M3R^−/− mice. Dotted lines indicate the mean mRNA expression of the respective LPS-treated control mice. Immunohistochemical staining for matrix metalloproteinase 13 (MMP13) (c–d), receptor activator of nuclear factor-κB ligand (RANKL) (g–h) and cathepsin K (k–l) in knee joint sections from male M3R^−/−-LPS (c, g and k) and M3R^−/−-CAIA (d, h and l) mice. Original magnification: 100× (c–d) and 400× (g–h and k–l). CAIA collagen antibody-induced arthritis,  Ctsk cathepsin K, LPS lipopolysaccharide, M3R M3 muscarinic acetylcholine receptor, Mmp13 matrix metalloproteinase 13, Rankl receptor activator of nuclear factor-κB ligand, WT wild-type