电磁场协同细胞膜片技术促进骨折愈合的效应及机制研究

The nonunion is a common problem during the fracture treatment. It has a long treatment cycle, limited treatment, and many other issues. Bone defect and periosteum damage of the fracture area are the significant reasons of the bone nonunion. Cell-sheet technology is a new cell processing and transplantation method, which is not dependent scaffold. This technology has been used in tissue reconstruction and/or tissue repair. Bone marrow mesenchymal stem cells (BMSCs) are adult multipotent stem cells with the potency of self-renewal and multilineage differentiation. The seed cells and class periosteum-like structure can be provided by transplanting the BMSCs cell-sheet to the fracture area. However, the source of the BMSCs is limited, the ability of self-renewal and multiple differentiation potential decreased during the subculture in vitro, the direction of differentiation is uncontrollable in vivo. All these limit its clinical application. The immediate effects of which electromagnetic fields treatment promote the BMSCs proliferation, induce the osteogenic and/or chondrogenic differentiation have been proved by many researches. This research investigates the legacy effect of the electromagnetic fields on BMSCs and uses it to establish abundant and with good biology properties cell-sheets, and then transplant them to the fracture area. The effect of these cell-sheets on fracture healing will be investigated. This may find a new and effective method to treatment nonunion and/or promote the healing of fracture.

骨折不愈合发病率较高、治疗周期长而疗效不确切。骨折区域的骨质缺失、骨膜受损是造成骨折不愈合的重要原因。细胞膜片技术作为一种不依赖细胞支架的新型细胞处理和移植技术，已用于组织缺损重建或/和组织修复。利用骨髓间充质干细胞构建的细胞膜片，可以为骨折愈合提供所需要的种子细胞和类骨膜样结构，从而促进骨折愈合。然而，骨髓间充质干细胞存在来源有限、体外培养过程中增殖及分化能力降低、移植后细胞分化方向不可调控等问题，限制了其临床应用。前期研究表明电磁场暴磁可以产生促进骨髓间充质干细胞增殖，增强其成骨、成软骨分化能力的即时效应。本项目拟探讨电磁场暴磁骨髓间充质干细胞的后续效应，并用其辅助构建具有良好生物学性能的骨髓间充质干细胞膜片，观察此种细胞膜片对骨折愈合的治疗效应。这可有助于探索一种新的、有效的促进骨折愈合的治疗方式。

骨折不愈合是临床医生经常面对的问题，虽然近年来对骨折的治疗有很大的发展，但是骨折不愈合的总体发生率仍在5%～10%，骨折不愈合的治疗周期长而疗效不确切。骨折区域的骨质缺失、骨膜受损是造成骨折不愈合的重要原因。细胞膜片技术作为一种不依赖细胞支架的新型细胞处理和移植技术，已用于组织缺损重建或/和组织修复。利用骨髓间充质干细胞构建的细胞膜片，可以为骨折愈合提供所需要的种子细胞和类骨膜样结构，从而促进骨折愈合。本研究利用低频电磁场预处理骨髓间充质干细胞，观察移除电磁场后骨髓间充质干细胞在增殖及成骨、成脂、成软骨方向分化能力的持续性变化。利用低频电磁场预处理骨髓间充质干细胞并构建干细胞细胞膜片，观察此种细胞膜片对骨折愈合的治疗效应。研究发现经电磁场预处理后骨髓间充质干细胞的增殖能力及成骨、成软骨方向分化能力得到持续性增强，向成脂方向分化的能力受到持续性抑制。在构建骨髓间充质干细胞细胞膜片过程中进行电磁场暴磁处理，得到的干细胞细胞膜片移植于大鼠骨折不愈合模型，能更好的促进大鼠骨折愈合。电磁场暴磁预处理骨髓间充质干细胞，能提高其增殖及成骨、成软骨分化能力，并且这种效应在电磁场移除后持续存在，这可能部分改善骨髓间充质干性在多次传代培养过程中自我复制及多向分化能力逐渐降低的问题。电磁场暴磁预处理得到的细胞膜片可以更好促进骨折愈合，这为后续利用干细胞移植治疗骨折不愈合打下一定基础。