破骨细胞抑制剂龙血素B靶向抑制活性氧治疗早期激素性股骨头坏死的机制研究

活血祛瘀中药保髋治疗激素性股骨头坏死（SIONFH）疗效显著，早期治疗可极大提高保髋成功率，但SIONFH早期病理机制仍不明确，中药药效靶点研究也难有突破。破骨细胞过度活跃引起的骨吸收、破坏是早中期SIONFH主要病理表现。申请人前期发现，骨坏死区活性氧水平增加，同时低表达Keap1/Nrf2/ARE信号轴下游抗氧化因子HO-1等；而龙血素B（活血圣药龙血竭单体）可下调破骨细胞及活性氧活性，促进HO-1表达，或可与Keap1蛋白稳定结合。因此，在SIONFH早期，激素或可下调Keap1/Nrf2/ARE信号轴，促进活性氧产生，增强破骨细胞活性；而龙血素B可激活该信号轴，防止活性氧、破骨细胞过度活跃，促进SIONFH骨修复。本项目拟采用药物靶点密切反应、基因沉默与过表达等技术，阐明龙血素B靶向结合Keap1以下调活性氧、破骨细胞活性的机制，揭示上述SIONFH早期病理机制及龙血素B疗效机制。

The administration of Chinese medicine of removing blood stasis has achieved remarkable effect on steroid-induced osteonecrosis of the femoral head (SIONFH) in clinic, and early treatment can greatly contribute to hip preservation, but the pathological mechanism of SIONFH at early stage still remains ambiguous, which makes it difficult to make a breakthrough in the target research of Chinese medicine. Bone resorption and destruction dominated by hyperactive osteoclasts were the main pathological manifestations of SIONFH at early and middle stages. Our recent studies have revealed that the production of reactive oxygen species was enhanced and the downstream antioxidant enzymes including HO-1 in Keap1/Nrf2/ARE axis were downregulated in necrosis area. Additionally, Loureirin B, one compound extracted from Sanguis Draxonis which was honored as the holy medicine in invigorating the circulation of blood, attenuated osteoclast activity and the production of reactive oxygen species, further upregulated HO-1 expression and could stably bind with Keap1 protein. Therefore, glucocorticoids could upregulate the production of reactive oxygen species, then enhance osteoclast activity through downregulating Keap1/Nrf2/ARE axis in early SIONFH. Theoretically, Loureirin B has osteonecrosis-repair effects on SIONFH via activating Keap1/Nrf2/ARE axis to further dampen hyperactive reactive oxygen species and osteoclasts. In present research, we intend to conduct in vitro and in vivo experiments including Drug Affinity Responsive Target Stability assay and Gene Silencing and Overexpression, to clarify the mechanism of Loureirin B binding with Keap1 protein to dampen the activities of reactive oxygen species and osteoclasts, and prove the clarified pathological mechanisms of early SIONFH and the effect mechanism of Loureirin B.