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This study aimed at the core pathological issue of femoral head osteonecrosis and constructed a 3D-printed bioactive magnesium alloy scaffold composite regeneration system integrating bone marrow mesenchymal stem cells in 3D microspheres. Through in vitro cell experiments and in vivo animal model experiments, it was verified that this system has good biocompatibility, can promote osteogenesis and angiogenesis differentiation, and shows significant effects in femoral head repair intervention in animal models. This system relies on the dual effects of magnesium ion release regulating the microenvironment and microspheres protecting stem cells, and through activating relevant signaling pathways to regulate the bone vascular microenvironment, it achieves synergistic repair of femoral head osteonecrosis, providing new research ideas for the regulation of bone vascular microenvironment in bone tissue engineering.
This review focuses on the regeneration and repair dilemma caused by the heterogeneity of bone-cartilage tissue, with the tissue engineering system combining mesenchymal stem cells and biomaterial scaffolds as the core, clarifies the regulatory mechanism of biological physical signals on the fate of stem cells, systematically summarizes the progress in the design of biomimetic microenvironment scaffolds under mechanical biology guidance, realizes the precise regulation of lineage-specific differentiation of mesenchymal stem cells, and provides theoretical support and design references for layered bone-cartilage regeneration, especially the regeneration repair of subchondral bone.
01 Research Background
This study aimed at the core pathological issue of femoral head osteonecrosis and constructed a 3D-printed bioactive magnesium alloy scaffold composite regeneration system integrating bone marrow mesenchymal stem cells in 3D microspheres. Through in vitro cell experiments and in vivo animal model experiments, it was verified that this system has good biocompatibility, can promote osteogenesis and angiogenesis differentiation, and shows significant effects in femoral head repair intervention in animal models. This system relies on the dual effects of magnesium ion release regulating the microenvironment and microspheres protecting stem cells, and through activating relevant signaling pathways to regulate the bone vascular microenvironment, it achieves synergistic repair of femoral head osteonecrosis, providing new research ideas for the regulation of bone vascular microenvironment in bone tissue engineering.
The tendon-bone transitional tissue has a highly specialized extracellular matrix structure, with the core feature being the hierarchical arrangement of collagen and the gradient composition of minerals. This structural system can achieve stable force transmission and guide the cell phenotype of spatial organization. Currently, it is impossible to precisely reproduce the complex multi-scale structure and composition gradient of the tendon-bone interface, which has become a key bottleneck hindering the integration and regeneration of soft and hard tissue interfaces, and requires the development of a biomimetic matrix construction scheme that conforms to the natural structure characteristics.
02 Main Content
Construct a composite regeneration system combining 3D microspheres carrying bone marrow mesenchymal stem cells and 3D-printed micro-hole bioactive magnesium alloy scaffolds; conduct in vitro detection of the biocompatibility of the composite system, explore its regulatory effects on osteogenic differentiation and angiogenic differentiation of cells; construct a steroid-induced femoral head necrosis rabbit model, and evaluate the in vivo repair effect of the composite system through micro-CT and histological analysis; analyze the mechanical support and ion release effects of the magnesium alloy scaffold, the protective effect of microspheres on stem cells, and the intrinsic mechanism of the composite system regulating cell interactions, activating extracellular matrix-related signaling pathways and PI3K-Akt signaling pathways to improve the bone vascular microenvironment.
03 Research Design
Adopt a dual-dimensional research scheme of in vitro cell experiments + in vivo animal experiments:
In vitro level, detect the biocompatibility of the composite regeneration system, analyze its induction effect on osteogenic differentiation and angiogenic-related cell differentiation of bone marrow mesenchymal stem cells;
In vivo level, construct a steroid-induced femoral head necrosis rabbit model, apply the composite system to the model in vivo, and systematically evaluate the repair effect of femoral head bone tissue through micro-CT and histological detection;
Mechanism level, explore the effects of magnesium ion release, the protective effect of microspheres on stem cells, and the molecular mechanism of the composite system regulating cell interactions, activating extracellular matrix-related signaling pathways and PI3K-Akt signaling pathways to improve the bone vascular microenvironment.
04 Results In vitro experiments have confirmed that this composite system has excellent biocompatibility and can effectively promote the osteogenic differentiation and angiogenic differentiation processes of cells;
In the rabbit femoral head necrosis model, both the micro-CT and histological test results indicated that the composite system had a significant intervention and repair effect on femoral head bone necrosis;
The magnesium alloy scaffold can provide sufficient mechanical support for the repair area and release magnesium ions to participate in the regulation of the bone microenvironment;
The three-dimensional microspheres loaded with bone marrow mesenchymal stem cells can stably combine with the scaffold, increasing the stem cell loading and providing a protective growth environment for the cells to avoid mechanical damage;
The composite system can regulate the interaction between bone marrow mesenchymal stem cells, osteoblasts and vascular endothelial cells, and by activating extracellular matrix organization, local adhesion and PI3K-Akt signaling pathways, regulate the bone vascular microenvironment related to osteoblasts, thereby promoting the repair of femoral head bone tissue.
05 Extension of the thinking
This study verified the synergistic bone repair potential of the release of bioactive metal ions combined with stem cell microsphere carriers, providing a new material design idea for the bone regeneration research of femoral head bone necrosis;
Based on the repair strategy of bone vascular microenvironment regulation, it can be extended to various bone defects and bone tissue degenerative disease regeneration research;
By optimizing the microstructure of the scaffold and the stem cell microsphere delivery system, further exploration of the fine regulation mechanism of cell communication and signal pathways during bone repair can be conducted, providing more theoretical support for the optimization and development of bone tissue engineering regeneration systems.
