Methods: We analyzed the expression of the genes involved in inflammasome in human periodontal-tissue component cells (periodontal ligament cells, gingival epithelial cells, alveolar bone-derived osteoblasts and gingival fibroblasts) by RT-PCR. We immunohistochemically stained mouse maxilla to assess in vivoexpression of caspase-1 and ASC. Further, we cultured human periodontal ligament cells in mineralization inducing medium (αMEM supplemented with 10% FCS, 50 μg/ml Ascorbic acid and 10 mM β-glycerophosphate) for 30 days and real-time PCR was then performed to analyze the expression of the genes involved in inflammasome during the course of differentiation of human periodontal ligament cells.
Results: Human periodontal-tissue component cells showed expression of genes involved in inflammasome, such as caspase-1, ASC and NLR, pyrin domain-containing-3 (NLRP3). Caspase-1 and ASC expressions were also observed in mouse periodontal tissues. Expression of caspase-1, P2X7 and NLRP3 were increased during the course of differentiation of human periodontal ligament cells to hard-tissue forming cells,.
Conclusions: These results suggest that inflammasome may be involved in homeostasis and regeneration of periodontal tissues.