Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan.
Department of Morphology, Universidade Federal Fluminense, Niteroi, Rio de Janeiro, Brazil.
J Orthop Res. 2020 Oct;38(10):2120-2130. doi: 10.1002/jor.24676. Epub 2020 Apr 6.
The Masquelet induced-membrane (IM) technique is indicated for large segmental bone defects. Attributes of the IM and local milieu that contribute to graft-to-bone union are unknown. Using a rat model, we compared global gene expression profiles in critically sized femoral osteotomies managed using a cement spacer as per Masquelet to those left empty. At the end of the experiment, IM and bone adjacent to the spacer were collected from the Masquelet side. Nonunion tissue in the defect and bone next to the empty defect were collected from the contralateral side. Tissues were subjected to RNA isolation, sequencing, and differential expression analysis. Cell type enrichment analysis suggested the IM and the bone next to the polymethylmethacrylate (PMMA) spacer were comparatively enriched for osteoblastic genes. The nonunion environment was comparatively enriched for innate and adaptive immune cell markers, but only macrophages were evident in the Masquelet context. iPathwayGuide was utilized to identify cell signaling pathways and protein interaction networks enriched in the Masquelet environment. For IM vs nonunion false-discovery rate correction of P values rendered overall pathway differences nonsignificant, and so only protein interaction networks are presented. For the bone comparison, substantial enrichment of pathways and networks known to contribute to osteogenic mechanisms was revealed. Our results suggest that the PMMA spacer affects the cut bone ends that are in contact with it and at the same time induces the foreign body reaction and formation of the IM. B cells in the empty defect suggest a chronic inflammatory response to a large segmental osteotomy.
诱导膜（IM）技术适用于大段骨缺损。IM 的特性和局部环境有助于移植物与骨的结合，但目前尚不清楚。本研究使用大鼠模型，比较了使用水泥间隔物按照 Masquelet 技术处理的临界尺寸股骨截骨术与未处理的股骨截骨术的全局基因表达谱。实验结束时，从 Masquelet 侧收集 IM 和靠近 spacer 的骨组织。从对侧收集未愈合组织和空缺陷处的骨组织。对组织进行 RNA 分离、测序和差异表达分析。细胞类型富集分析表明，IM 和靠近聚甲基丙烯酸甲酯（PMMA） spacer 的骨组织相对富含成骨细胞基因。未愈合环境相对富含固有和适应性免疫细胞标志物，但在 Masquelet 环境中仅可见巨噬细胞。iPathwayGuide 用于识别细胞信号通路和富含 Masquelet 环境的蛋白质相互作用网络。对于 IM 与非愈合组织，假发现率校正 P 值的整体通路差异无统计学意义，因此仅呈现蛋白质相互作用网络。对于骨组织的比较，揭示了大量已知参与成骨机制的途径和网络的富集。我们的结果表明，PMMA spacer 影响与之接触的截骨骨端，同时诱导异物反应和 IM 的形成。空缺陷中的 B 细胞提示对大段骨切除术的慢性炎症反应。
