Bone Abstracts

Tannerella forsythia is a gram-negative, anaerobic, asaccharolytic, fusiform bacterium. The presence of the bacterium is associated with various forms of periodontal disease, including gingivitis, chronic and aggressive periodontitis. The expression of GroEL, a bacterial heat shock protein, increases in stressful conditions such as infection. GroEL is a moonlighting protein that has multiple functions. The aim of this study was to evaluate the effect of T. forsythia GroEL alone or GroEL in the presence of IL-17 on bone resorption. BALB/c mice were injected with T. forsythia GroEL (20–50 μg/mouse) and/or IL-17 (1 μg/mouse) subcutaneously over the calvaria daily for 5 days. On day 7 after the first administration, mice were sacrificed and bone resorption in the calvaria was analyzed by micro-CT and TRAP staining. T. forsythia GroEL increased the area of bone resorbed and the size and the number of the resorption spots. IL-17 synergistically enhanced GroEL-induced bone resorption. These results suggest that T. forsythia GroEL alone or in the presence of IL-17 may play an important role in modulating bone resorption which is a characteristic of periodontitis.