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

Figure 3

Muramyl dipeptide (MDP) enhances lipopolysaccharide- (LPS-) induced bone destruction in mouse calvariae. (a) Microfocus computed tomography reconstruction images of mouse calvariae harvested after 5 days of daily administration of PBS (A), 10 μg/day LPS (B), 100 μg/day MDP (C), 100 μg/day LPS (D), or 10 μg/day LPS + 100 μg/day MDP (E). Red areas indicate larger areas of bone destruction. (b) Ratio of bone destruction area to total area. Results are expressed as the mean ± SD (; ; ). Differences were determined using Scheffe’s test. (c) Levels of TRACP 5b in mouse serum in vivo. Serum was obtained from mice after five days of daily administration into the calvariae. Circulating levels of tartrate-resistant acid phosphatase (TRACP 5b) were determined by enzyme-linked immunosorbent assay (ELISA). Results are expressed as the mean ± SD (; ). (d) Levels of C-terminal telopeptide fragments of type I collagen in mouse serum in vivo. Circulating levels of C-terminal telopeptide fragments of type I collagen were determined by Mouse CTX Assay kit. Results are expressed as the mean ± SD (; ; ). Differences were determined using Scheffe’s test.

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