Zanthoxylum piperitum reversed alveolar bone loss of periodontitis via regulation of bone remodeling-related factors

Ethnopharmacological relevance: Zanthoxylum piperitum (ZP) has been used to prevent toothache in East Asia. Aim of study: In this study, we investigated the effects of ZP on periodontitis along with alveolar bone loss. Materials and methods: Twenty-eight male Sprague-Dawley rats were assigned into 4 groups; non-ligated (NOR), ligated and treated vehicle (CTR), ligated and treated 1 mg/mL ZP (ZP1), and ligated and treated 100 mg/mL ZP (ZP100). Sterilized 3-0 nylon ligature was placed into the subgingival sulcus around the both sides of mandibular first molar. After topical application of 1 and 100 mg/mL ZP for 2 weeks, mandibles was removed for histology. In addition, SaOS-2 osteoblast cells were treated 1, 10 and 100 mu g/mL ZP for 24 h to analyze the expressions of alveolar bone-related markers. Results: Several alveolar bone resorption pits, which indicate cementum demineralization were decreased by ZP treatment. Topical ZP treatment inhibited periodontitis-induced alveolar bone loss. In addition, there were significant reduction of osteoclastic activities following topical ZP treatment in periodontium. The expression of RANKL was decreased in SaOS-2 osteoblast cells by treating ZP, while that of OPG was increased. ZP treatment increased the expressions of Runx2 and Osterix in SaOS-2 cells. Conclusion: In summary, ZP treatment inhibited alveolar bone loss as well as maintained the integrity of periodontal structures via regulation of bone remodeling. ZP may be a therapeutic target for treating periodontitis.