Effects of whole cell sonicates of Treponema lecithinolyticum on osteoclast differentiation

Background: Alveolar bone destruction is a characteristic feature of period ontal diseases and multinucleated osteoclast cells derived from hemopoietic cells are responsible for bone resorption. Treponema lecithinolyticum is a novel oral spirochete isolated from the periodontal lesions. Methods: The effect of whole cell sonicates on the osteoclast differentiati on was examined in a co-culture system of hemopoietic mouse bone marrow cel ls and calvaria derived-osteoblastic cells to clarify the role of T. lecith inolyticum in the alveolar bone destruction associated with periodontal dis eases. The differentiated osteoclasts were confirmed by tartrate-resistant acid phosphatase (TRAP) staining. Results: Sonicates of this bacterium stimulated the osteoclast formation in the co-culture system in a dose-dependent manner. The sonicates-induced os teoclast formation was partially inhibited by the heat treatment of sonicat es. Indomethacin, which is a prostaglandin inhibitor, decreased the osteocl ast formation induced by the bacterial sonicates. Conclusions: These findings suggest that T. lecithinolyticum induces osteoc last differentiation by a prostaglandin E-2-dependent mechanism and that he at-labile components may be involved in this process.