The interaction between immune cells and bone forming cells plays a vital role in maintaining the homeostasis of the skeletal system, and is regulated by the three-dimensional structure of tissues. Whether the construction of biomaterials can activate or reproduce this spatial “cross-talk” between immune cells and bone forming cells in bone natural formation process is a prerequisite for successful fracture healing and bone regeneration. Herein, a bone marrow mesenchymal stem cells (MSCs)/macrophages-laden Haversian bone-mimicking bioceramic scaffold was successfully prepared through the biomimetic design of biomaterials and 3D printing technology. MSCs and macrophages were respectively distributed in the cancellous bone and Haversian canals of the scaffold to simulate the three-dimensional structure regulation of the cell spatial distribution and multiple intercellular interaction in natural bone tissue, and worked in concert to modulate the scaffold material-mediated osteo-immune microenvironment. The in vitro study revealed that the pro-inflammatory response of macrophages was more significantly inhibited when distributed with MSCs in the scaffolds at a cell ratio of 0.5:1 for co-culture, in comparison with multicellular culture at other ratios and unicellular culture. Meanwhile, MSCs exhibited the relatively high osteogenic potential, most likely via the activation of certain key signaling pathways mediated by macrophages-derived paracrine signaling mediators (OSM, BMP-2, and WNT10b). This work not only establishes a bionic platform for the regulation of multicellular osteo-immune response and regeneration but also offers a promising tissue-engineered biomimetic scaffold with improved immunomodulatory function for promoting bone tissue regeneration.

免疫细胞与成骨细胞之间的相互作用对维持骨骼系统的稳态起着至关重要的作用，并受组织三维结构的调控。生物材料的构建能否在骨自然形成过程中激活或再现免疫细胞与骨形成细胞之间的这种空间“串扰”，是骨折愈合和骨再生成功的先决条件。在此，通过生物材料的仿生设计和3D打印技术，成功制备了载有骨髓间充质干细胞（MSCs）/巨噬细胞的哈弗氏骨模拟生物陶瓷支架。MSCs和巨噬细胞分别分布在支架的松质骨和哈弗氏管中，模拟天然骨组织中细胞空间分布的三维结构调控和多种细胞间相互作用，协同调节支架材料介导的骨- 免疫微环境。这体外研究表明，与其他比例的多细胞培养和单细胞培养相比，当与支架中的 MSC 以 0.5:1 的细胞比例分布进行共培养时，巨噬细胞的促炎反应受到更显着的抑制。同时，MSCs 表现出相对较高的成骨潜力，最有可能是通过激活巨噬细胞衍生的旁分泌信号介质（OSM、BMP-2 和 WNT10b）介导的某些关键信号通路。这项工作不仅建立了一个用于调节多细胞骨免疫反应和再生的仿生平台，而且提供了一种有前途的组织工程仿生支架，具有改善的免疫调节功能，可促进骨组织再生。