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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矿化的胶原蛋白修饰的PMMA水泥可增强骨整合度，并减少腰椎间盘退变疾病的治疗过程中的纤维包裹。

作为微创外科手术，现在考虑经皮骨水泥椎间盘成形术（PCD）来治疗老年人群的腰椎间盘退变疾病。在这里，我们调查了成骨的矿化胶原蛋白（MC）改性的聚甲基丙烯酸甲酯（PMMA）水泥是否可以作为PCD手术的合适材料。表征了MC改性的PMMA（PMMA-MC）的可注射性，亲水性和机械性能。MC的引入并没有改变PMMA的应用和凝固时间，并且易于在微创手术中进行处理。PMMA-MC的亲水性得到了极大的改善，其弹性模量经过定制，可补充动应力下骨骼的机械性能。然后，通过植入PMMA-MC或PMMA在山羊椎间盘变性诱发的模型中进行PCD手术。植入后三个月，微计算机断层扫描分析显示，与单独的PMMA相比，PMMA-MC与骨骼之间的圆周接触指数高36.4％。组织学染色证实，PMMA-MC的表面与新骨直接接触，而PMMA被纤维组织覆盖。观察到在植入物周围观察到的巨噬细胞聚集是纤维包囊的原因。因此，在体外研究了PMMA和PMMA-MC与巨噬细胞的相互作用。我们发现添加MC可能会阻止巨噬细胞的增殖和融合。此外，在与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。