骨折愈合期间除新骨生成外，骨吸收同时存在且两者保持动态平衡，其效应细胞：成骨细胞（Ob）与破骨细胞(Oc)如何维持平衡？近期研究指出，核转录因子MITF是Oc活化过程中重要的转录因子；而Ob可能通过RANKL/RANK/MITF通路调控Oc活性以维持骨形成与骨吸收的耦联平衡。愈骨葆方是经民间长期实践验证具有确切接骨作用的中药验方。前期工作证实此方能显著增加Ob分化活性及矿化功能，且能明显上调成骨功能相关基因（OPN与COL-Ⅰ）的表达。虽然愈骨葆方在促进骨再生方面具有优势疗效，但其关键分子机理仍未明。本课题拟在前期研究基础上，利用骨系细胞和骨折修复动物模型，从组织、细胞和分子水平研究愈骨葆方在治疗过程中对骨生成和骨吸收的影响，及其是否通过调控RANKL/RANK/MITF通路而介导两者的耦联关系。本研究有助于揭示愈骨葆方促骨折愈合的疗效机制，为研发高效安全的接骨类新型中成药提供科学基础。

New bone formation and bone resorption are both exist and maintain a homeostasis in the union of fracture, but how their effector cells: osteoblasts (Ob) and osteoclasts (Oc) to maintain such a balance is not clear? Recent studies have indicated that the nuclear transcription factor: MITF is an important transcription factor in the Oc activation process, it regulate Oc in the formation of proteinase K; Ob may affect Oc activity via the RANKL / RANK / MITF pathway in order to maintain the coupling balance of bone formation and bone resorption. Such an associated balance plays an important role in union of fracture. YuGuBao is a traditional Chinese medicine prescription which composed of 12 herbs, its excellent efficacy in fracture treatment has been verifying after long-term clinic practice. Our preliminary work has confirmed that YuGuBao significantly increase the differentiation and mineralization of osteoblasts, and can significantly up-regulated the expression of osteogenesis genes (OPN and COL-I). Although YuGuBao has an advantage in promoting osteanagenesis during union of fracture, but the key molecular mechanism remains unclear. Base on the preliminary studies, this project intends to investigate the effect of YuGuBao on bone formation and bone resorption by using the bone lineage cells and fracture animal models, and whether the bone formation and bone resorption coupled relationship are regulated via the RANKL / RANK / MITF pathway. This study will reveal the mechanism of YuGuBao in promote fracture healing, and to provide the scientific basis for the development of a new, efficient and safe Chinese medicine.