Abstract：
To investigate the effect and mechanism of simvastatin on cell components of tendon-bone healing interface. The tendon-bone healing model was established by inserting the end of the Achilles tendon into the tibial tunnel on 24 rats, and simvastatin was used locally at the tendon-bone interface. Healing was evaluated at 8 weeks by mechanical testing, micro-CT, and qualitative histology including H&E, Toluidine blue, and immunohistochemical staining. In vitro, bone marrow stromal cells (BMSCs) and tendon-derived mesenchymal stem cells (TDSCs) underwent osteogenic and chondrogenic differentiation respectively by plate co-culture. An analysis was performed on days 7 and 14 of cell differentiation. Biomechanical testing demonstrated a significant increase in maximum stiffness in the simvastatin-treated group. Micro-CT analysis showed that the bone tunnels in the simvastatin group were smaller in diameter and had higher bone density. H&E and Toluidine blue staining demonstrated that tendon-bone healing was significantly greater with better tissue arrangement and more extracellular matrix in the simvastatin-treated group than that in the control group, and immunohistochemical staining showed the expression of VEGF in simvastatin group was significantly higher. Histological staining and RT-PCR confirmed that simvastatin could promote the differentiation of co-cultured BMSCs and TDSCs into osteoblasts and chondroblasts, respectively. The effect of promoting osteogenic differentiation was more tremendous at 14 days, while its effect on promoting chondroblast differentiation was more evident on the 7th day of differentiation. In conclusion, local administration of simvastatin can promote the tendon-bone healing by enhancing neovascularization, chondrogenesis, and osteogenesis in different stages of the tendon-bone healing process.
摘要：
探讨辛伐他汀对腱-骨愈合界面细胞成分的影响及其机制。方法将跟腱末端插入胫骨隧道,建立24只大鼠的腱-骨愈合模型,在肌腱-骨界面局部使用辛伐他汀。通过机械测试在8周时评估愈合情况，Micro-CT,和定性组织学，包括H&E，甲苯胺蓝,和免疫组织化学染色。体外，骨髓基质细胞（BMSCs）和肌腱间充质干细胞（TDSCs）通过平板共培养分别进行成骨和软骨分化。在细胞分化的第7天和第14天进行分析。生物力学测试表明，辛伐他汀治疗组的最大刚度显着增加。Micro-CT分析表明，辛伐他汀组的骨隧道直径较小，骨密度较高。H＆E和甲苯胺蓝染色表明，辛伐他汀治疗组的腱-骨愈合明显大于对照组，组织排列更好，细胞外基质更多。免疫组化染色显示辛伐他汀组VEGF表达显著增高。组织学染色和RT-PCR证实辛伐他汀能促进共培养的BMSCs和TDSCs向成骨细胞和成软骨细胞分化,分别。14天时促进成骨分化的作用更大,而其促进成软骨细胞分化的作用在分化第7天更为明显。总之,辛伐他汀的局部给药可以通过增强新生血管形成来促进腱-骨愈合，软骨形成,和骨生成在腱-骨愈合过程的不同阶段。
