Capsaicin, a TRPV1 Ligand, Suppresses Bone Resorption by Inhibiting the Prostaglandin E Production of Osteoblasts, and Attenuates the Inflammatory Bone Loss Induced by Lipopolysaccharide
Figure 1
The effects of capsaicin on LPS-induced osteoclast formation and PGE2 production in cocultures of osteoblasts and bone marrow cells and on the bone-resorbing activity induced by LPS in mouse calvarial organ cultures. (a) Chemical structure of capsaicin. (b) Mouse bone marrow cells and osteoblastic cells were cocultured for 7 days with 30 μM capsaicin in the presence of LPS (1 ng/mL). The cells were stained for tartrate-resistant acid phosphatase (TRAP), a specific marker for osteoclasts, and the number of TRAP-positive multinucleated cells containing 3 or more nuclei was counted. The data are expressed as the mean ± SEM of 4 independent wells. (c) The level of PGE2 was measured by EIA using the conditioned medium of the cocultures. (d) Mouse calvariae were dissected in half and cultured with or without capsaicin (30 μM) in the presence of LPS (1 μg/mL) for 5 days. The concentration of calcium in the medium was measured to calculate bone-resorbing activity. Data are expressed as the mean ± SEM of 4 independent wells. A significant difference between the two groups is indicated, * versus control; # versus LPS; ## versus LPS.
