EDTMP导向淫羊藿苷主动骨靶向纳米脂质体对骨代谢的调节作用及其机制研究

Herba Epimedii (HE) is a traditional Chinese medicine herb used in treating of osteoporosis. In our previous study, we found that Icariin (ICA), the active constituent of HE, can promote osteoblast differentiation and inhibit osteoclastic bone resorption, suggesting that Icariin has the great potential in the prevention and treatment of osteoporosis. However, its potential clinical application was limited by the low water solubility and poor bioavailability after oral administration. In response to these issues, hydroxyapatite (HA) was designed as the targeting for the delivery of Icariin with passive and active bone marrow-targeting nanoliposomes (ICA-BMTNL) by using the phagocytosis of bone marrow macrophage and the special affinity of ethylenediamine tetramethyl phosphonic acid (EDTMP) to HA. The effects of ICA-BMTNL on bone metabolism will be evaluated in osteoblasts and ovariectomized rat osteoporosis model. To assess the safety of nanomaterials, the uptake and tissue distribution of ICA-BMTNL in rats will also be investigated. In addition to explore the role of ICA-BMTNL on known targets, possible new targets and mechanism of action will be identified by Osteogenesis PCR array and metabolomics. The present proposal was designed to clarify the possible regulatory effect of ICA-BMTNL in regulating bone metabolism and verify its advantages, and explore the potential targets and possible signaling pathway of Icariin. The current proposal will create a new option for the development of new drugs with high efficiency and low toxicity in the treatment of osteoporosis, and promote the application of modern technologies in the reform of preparation and dosage forms of traditional Chinese medicine.

淫羊藿是治疗骨质疏松的传统中药，前期研究中我们发现其活性成分淫羊藿苷能促进成骨细胞分化，抑制破骨细胞骨吸收，提示淫羊藿苷在骨质疏松防治中极具研究价值。但是淫羊藿苷溶解性不好，导致口服吸收差，生物利用度低，这极大限制其临床应用。针对上述问题，本课题以羟基磷灰石为靶点，利用乙二胺四甲叉膦酸（EDTMP）对羟基磷灰石的特殊亲和力及骨髓巨噬细胞的吞噬作用，首次将淫羊藿苷设计成EDTMP导向主动及被动骨靶向纳米脂质体，研究其对成骨细胞及去势大鼠骨代谢的影响，配合基因芯片和代谢组学技术进一步研究其可能的新靶点和作用机制。同时，兼顾纳米粒子的安全性，考察其组织分布及对主要脏器的影响。本课题旨在以整体动物及细胞为模型，阐明淫羊藿苷新型骨靶向纳米脂质体对骨代谢的调节作用及其作用靶点和信号通路，推动“纳米中药”的现代化研究，为开发高效、低毒的骨质疏松治疗药物提供新思路，对于传统中药现代剂型改造具有重要意义。

淫羊藿是治疗骨质疏松的传统中药，前期研究中我们发现其活性成分淫羊藿苷能促进成骨细胞分化，抑制破骨细胞骨吸收，提示淫羊藿苷在骨质疏松防治中极具研究价值。但是淫羊藿苷溶解性不好，导致口服吸收差，生物利用度低，这极大限制其临床应用。针对上述问题，本课题以羟基磷灰石为靶点，利用乙二胺四甲叉膦酸（EDTMP）对羟基磷灰石的特殊亲和力及骨髓巨噬细胞的吞噬作用，首次将淫羊藿苷设计成EDTMP导向主动及被动骨靶向纳米脂质体，研究其对成骨细胞及去势大鼠骨代谢的影响和作用机制。研究结果表明，淫羊藿苷主要通过雌激素受体途径上调了成骨细胞核心结合因子（Runx2/Cbfa1）、骨形态发生蛋白2（Bmp2）和I型胶原（Col1）等基因的表达，促进成骨细胞的分化和矿化；进一步研究其作用涉及9个功能组别的33个基因差异化表达。淫羊藿苷、淫羊藿苷主动及被动骨靶向纳米脂质体连续给药13周后，给药组均能明显增加去卵巢大鼠股骨的骨密度，有效改善去卵巢大鼠骨生物力学性能，显著抑制去卵巢大鼠血清骨钙素（OCN）、I型前胶原氨基端肽（PINP）及I型胶原交联型羧基端肽（CTX）)的提高从而有效改善去卵巢大鼠的骨转换率。此外，淫羊藿苷及其主动和被动骨靶向纳米脂质体能有效增加大鼠股骨干骺端骨小梁厚度和减少骨小梁分离度，改善去势大鼠骨质疏松模型骨小梁微结构破坏特征。上述实验中，淫羊藿苷主动及被动骨靶向纳米脂质体对去势骨质疏松模型的各种指标改善上表现出比淫羊藿苷更强的作用优势。本研究对于推动“纳米中药”的现代化研究，为开发高效、低毒的骨质疏松治疗药物提供了新的思路，对于传统中药现代剂型改造具有重要借鉴意义。