巨噬细胞极化在骨修复中起着非常重要的作用。骨修复材料在植入体内后,会引起巨噬细胞的响应,使其向M1/M2极化,从而影响材料的成骨效果。本文制备了掺锶量分别为0%,5%,10%和15%摩尔百分比的锶掺杂微纳米生物活性玻璃(Sr-MNBG),并研究了不同掺锶量的Sr-MNBG对巨噬细胞极化的影响；随后,在此基础上研究了不同掺锶量Sr-MNBG调控的巨噬细胞分泌成分对小鼠骨髓间充质干细胞(mMSCs)向成骨分化的影响；最后,通过体内原位骨缺损修复实验验证了不同掺锶量Sr-MNBG对巨噬细胞极化的调控作用及其体内成骨作用。体外实验结果显示,掺锶量为5%,10%和15%的Sr-MNBG较掺锶量为0%的Sr-MNBG更能促进巨噬细胞向M2极化,其中10%掺锶量的Sr-MNBG具有最强的促巨噬细胞M2极化作用,且10%掺锶量的Sr-MNBG调控的巨噬细胞分泌成分更有利于成骨。体内实验结果表明,不同掺锶量的Sr-MNBG植入到体内后,10%掺锶量的Sr-MNBG周围有更多的M2巨噬细胞浸润,且表现出更好的骨修复效果,与体外实验结果相一致。因此,Sr-MNBG有望作为一种富有前景的免疫调控材料应用于骨修复。

Macrophage polarization plays an important role in bone repair. Once being implanted in the body, bone repair materials will trigger response of macrophage, making it switch to M1/M2 phenotype, thus affect the osteogenic effect of the material. In this work, Strontium-substituted micro/nano bioactive glasses (Sr-MNBG)with 0, 5%, 10% and 15% molar percent of strontium element were prepared, and the effect of Sr-MNBG on macrophage polarization was studied. Subsequently, the effects of Sr-MNBG with different strontium incorporation ratio on the osteogenic differentiation of murine bone marrow mesenchymal stem cells (mMSCs) were evaluated. Finally, the in vivo assessment was conducted to verify the polarization of macrophage and osteogenesis of Sr-MNBG through in situ bone defect repair experiment. The in vitro results showed that compared with 0%Sr-MNBG,Sr-MNBG with 5%, 10% and 15% molar percent of strontium element could further promote macrophage polarization toward M2, and 10%Sr-MNBG displayed the best effect. Moreover, the secretion of macrophages modulated by 10%Sr-MNBG was more beneficial to osteogenesis. The in vivo results showed that there were more M2 macrophages around 10%Sr-MNBG after implantation in the body, and better bone repair effect was found in the 10%Sr-MNBG group, which were consistent with the in vitro results. Therefore, Sr-MNBG is expected to be a promising immunoregulatory material for bone repair.