As a minimally invasive surgery, percutaneous cement discoplasty (PCD) is now contemplated to treat lumbar disc degeneration disease in elder population. Here, we investigated whether the osteogenic mineralized collagen (MC) modified polymethylmethacrylate (PMMA) cement could be a suitable material in PCD surgery. Injectability, hydrophilicity and mechanical properties of the MC-modified PMMA (PMMA-MC) was characterized. The introduction of MC did not change the application and setting time of PMMA and was easy to be handled in minimally invasive operation. Hydrophilicity of PMMA-MC was greatly improved and its elastic modulus was tailored to complement mechanical performance of bone under dynamic stress. Then, PCD surgery in a goat model with induced disc degeneration was performed with implantation of PMMA-MC or PMMA. Three months after implantation, micro-computed tomography analysis revealed a 36.4% higher circumferential contact index between PMMA-MC and bone, as compared to PMMA alone. Histological staining confirmed that the surface of PMMA-MC was in direct contact with new bone, while the PMMA was covered by fibrous tissue. The observed gathering of macrophages around the implant was suspected to be the cause of fibrous encapsulation. Therefore, the interactions of PMMA and PMMA-MC with macrophages were investigated in vitro. We discovered that the addition of MC could hinder the proliferation and fusion of the macrophages. Moreover, expressions of fibroblast-stimulating growth factors, insulin-like growth factor, basic fibroblast growth factor and tumor necrosis factor-β were significantly down-regulated in the macrophages cocultured with PMMA-MC. Together, the promoted osteointegration and reduced fibrous tissue formation observed with PMMA-MC material makes it a promising candidate for PCD surgery.

中文翻译：

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矿化胶原改性 PMMA 水泥在腰椎退行性椎间盘疾病的治疗中可增强骨整合并减少纤维包裹。


作为一种微创手术，经皮骨水泥椎间盘成形术（PCD）现在被认为可以治疗老年人群的腰椎间盘退变疾病。在这里，我们研究了成骨矿化胶原 (MC) 改性聚甲基丙烯酸甲酯 (PMMA) 水泥是否适合 PCD 手术的材料。对 MC 改性 PMMA (PMMA-MC) 的可注射性、亲水性和机械性能进行了表征。 MC的引入并没有改变PMMA的应用和凝固时间，并且易于微创操作操作。 PMMA-MC的亲水性得到极大改善，其弹性模量经过调整以补充动态应力下骨的机械性能。然后，在诱导椎间盘退变的山羊模型中进行 PCD 手术，植入 PMMA-MC 或 PMMA。植入三个月后，微型计算机断层扫描分析显示，与单独的 PMMA 相比，PMMA-MC 与骨之间的圆周接触指数高出 36.4%。组织学染色证实PMMA-MC表面与新生骨直接接触，而PMMA则被纤维组织覆盖。观察到的植入物周围巨噬细胞的聚集被怀疑是纤维包封的原因。因此，在体外研究了PMMA和PMMA-MC与巨噬细胞的相互作用。我们发现MC的添加会阻碍巨噬细胞的增殖和融合。此外，与PMMA-MC共培养的巨噬细胞中成纤维细胞刺激生长因子、胰岛素样生长因子、碱性成纤维细胞生长因子和肿瘤坏死因子-β的表达显着下调。 总之，PMMA-MC 材料促进骨整合并减少纤维组织形成，使其成为 PCD 手术的有希望的候选者。