RESUMO
It is a new hot pot in tissue engineering and regenerative medicine to study the effects of physicochemical properties of implanted biomaterials on regulating macrophage polarization to promote bone regeneration. In this study, we designed and fabricated mineralized collagen (MC) with different microporous structures via in vitro biomimetic mineralization method. The microporous structures, mechanical properties, shore hardness and water contact angle measurements were tested. Live/dead cell staining, CCK-8 assay, phalloidine staining, staining of focal adhesions were used to detect cell behavior. ELISA, qRT-PCR, ALP, and alizarin red staining (ARS) were performed to appraise osteogenic differentiation and investigated macrophage response and their subsequent effects on the osteogenic differentiation. The results showed that RAW264.7 and MC3T3-E1 cells were able to survive on the MC. MC with the microporous structure of approximately 84 µm and 70%-80% porosity could promote M2 macrophage polarization and increase the expression level of TGF-ß and VEGF. Moreover, the gene expression of the osteogenic markers ALP, COL-1, and OCN increased. Therefore, MC with different microporous structures mediated osteoimmunomodulation in bone regeneration. These data will provide a new idea of biomaterials inducing bone repair and direct the optimal design of novel immune biomaterials, development, and rational usage.
RESUMO
Zn-based alloys are considered as new kind of potential biodegradable implanted biomaterials recently. The difficulty of metal implanted biomaterials and bone tissue integration seriously affects the applications of metal implanted scaffolds in bone tissue-related fields. Herein, we self-designed Zn0.8Mn and Zn0.8Mn0.1Li alloys and CaP coated Zn0.8Mn and Zn0.8Mn0.1Li alloys, then evaluated the degradation property and cytocompatibility. The results demonstrated that the Zn0.8Mn0.1Li alloys had profoundly modified the degradation property and cytocompatibility, but Zn0.8Mn0.1Li alloys had particularly adverse effects on the surface morphology of osteoblasts. The results furtherly showed that the CaP-coated Zn0.8Mn and Zn0.8Mn0.1Li alloys scaffold had better biocompatibility, which would further guarantee the biosafety of this new kind of biodegradable Zn-based alloys implants for future clinical applications.
RESUMO
The effective healing of a bone defect is dependent on the careful coordination of inflammatory and bone-forming cells. In the current work, pro-inflammatory M1 and anti-inflammatory M2 macrophages were co-cultured with primary murine bone mesenchymal stem cells (BMSCs), in vitro, to establish the cross-talk among polarized macrophages and BMSCs, and as well as their effects on osteogenesis. Meanwhile, macrophages influence the osteogenesis of BMSCs through paracrine forms such as exosomes. We focused on whether exosomes of macrophages promote osteogenic differentiation. The results indicated that M1 and M2 polarized macrophage exosomes all can promote osteogenesis of BMSCs. Especially, M1 macrophage-derived exosomes promote osteogenesis of BMSCs through microRNA-21a-5p at the early stage of inflammation. This research helps to develop an understanding of the intricate interactions among BMSCs and macrophages, which can help to improve the process of bone healing as well as additional regenerative processes by local sustained release of exosomes.