Muramyl Dipeptide Enhances Lipopolysaccharide-Induced Osteoclast Formation and Bone Resorption through Increased RANKL Expression in Stromal Cells

Figure 2

Osteoclast formation is dependent on muramyl dipeptide (MDP) concentration. (a) Osteoclast number in the sutures following treatment with a low concentration of lipopolysaccharide (LPS) (10 μg/day) with increasing concentrations of MDP for 5 days. Sections were stained with tartrate-resistant acid phosphatase (TRAP) staining and counterstained with hematoxylin. Cells that stained red are considered to be TRAP-positive. Scale bars = 50 μm. (b) Number of TRAP-positive cells with three or more nuclei in the calvariae (; ). (c) Osteoclast number in the bone/marrow interface following treatment with a low concentration of lipopolysaccharide (LPS) (10 μg/day) with increasing concentrations of MDP for 5 days. Sections were stained with tartrate-resistant acid phosphatase (TRAP) staining and counterstained with hematoxylin. Cells that stained red are considered to be TRAP-positive. Scale bars = 100 μm. (d) The percentage of bone/marrow interface covered by osteoclasts was histomorphometrically determined in specimens (; ). Differences were detected using Scheffe’s test.

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