The demineralized bone matrix (DBM) is the most widely used bone allograft, which is obtained by removing the mineral component of bone, leading to exposure of the proteins responsible for osteoinduction. For clinical use, DBM shall be formulated with a carrier that provides consistency and improves its osteoinduction. In this study, three DBM formulations with glycerol (Gly), hyaluronic acid (HA), and gelatin methacryloyl (GelMA) were evaluated measuring their physicochemical properties (microstructure, compressive strength, and serum cohesivity) and their osteoinductive capacity both in vitro using C2C12 cells and umbilical cord human mesenchymal stem cells and in vivo in an ectopic bone formation model in athymic mice. To assess the effectiveness of DBM in vitro in inducing the differentiation into osteoblasts, alkaline phosphatase (ALP) activity was assessed in combination with a cytotoxicity assay. In vivo, new bone formation was assessed by histological and radiological analysis. In the compression and in the serum cohesive assays, the GelMA DBM formulation showed its superiority over the other formulations. In addition, GelMA showed a more compact structure analysed by scanning electron microscopy. Higher cell toxicity was observed on Gly formulations in vitro, whereas GelMa and HA showed very low toxicity. All formulations significantly improved ALP activity compared with control. In the in vivo studies, GelMA showed the greatest osteoinductive potential with a higher percentage of new bone and bone marrow formation. Our results suggest GelMA is useful as a carrier for DBM designed to promote the formation of the new bone.

中文翻译：

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明胶甲基丙烯酰基配方改善了脱矿骨基质的物理和骨诱导性能。

脱矿质骨基质（DBM）是使用最广泛的同种异体骨，它是通过去除骨骼的矿物质成分而获得的，从而导致负责骨诱导的蛋白质暴露出来。对于临床用途，DBM应与可提供一致性并改善其骨诱导作用的载体一起配制。在这项研究中，使用C2C12对三种具有甘油（Gly），透明质酸（HA）和明胶甲基丙烯酰基（GelMA）的DBM制剂进行了评估，以测量其理化性质（微观结构，抗压强度和血清凝聚力）以及它们的骨诱导能力。细胞和脐带人间充质干细胞以及无胸腺小鼠体内异位骨形成模型中的体内。为了评估DBM体外诱导分化为成骨细胞的有效性，结合细胞毒性试验评估了碱性磷酸酶（ALP）的活性。在体内，通过组织学和放射学分析评估了新的骨形成。在压缩和血清黏附测定中，GelMA DBM配方显示出优于其他配方的优势。另外，GelMA显示出通过扫描电子显微镜分析的更紧凑的结构。在体外对Gly制剂观察到较高的细胞毒性，而GelMa和HA显示出非常低的毒性。与对照相比，所有制剂均显着改善了ALP活性。在体内研究中，GelMA显示出最大的骨诱导潜力，并具有更高的新骨和骨髓形成百分比。我们的结果表明，GelMA可用作DBM的载体，旨在促进新骨的形成。