外周血MSC逆转半月板细胞的去分化及其体内修复半月板缺损的研究

Meniscal repair after injury have always been the challenge in sports medicine field both for basic research and clinical treatment due to the special blood supply and the mechanical environment of meniscus. Compared to uncontrollability and uncertainty of stem cell's differentiation, autologous meniscal fibrocartilage cells (MFC) have long been considered to be the best source of seed cells for meniscal regeneration. However, the limited cell number and dedifferentiation phenomenon in vitron limit their application. Our previous study has found that the peripheral blood derived mesenchymal stem cells (PB-MSC) have promising prospect in clinic due to their easy accessibility with minimal invasion, excellent chondrogenesis and the ability of accomplishing autologous transplantation in clinic. This study aims to establish a co-culture system of peripheral blood MSC and dedifferentiated MFC, in which MFC's dedifferentiation could be reversed by the paracrine secretion which is the trophic effects of MSC, thereby restoring the phenotypic characteristics of MFC; and to further explore the underlying mechanism of MFC's dedifferentiation and redifferentiation, whether this process can be regulated by HIF1?'s regulation on transcription factor SOX9. With wide variety of sources, bioactive 3D porous heterologous demineralized cancellous bone whose main ingredient is collagen type I, similar to that of meniscus's extracellular matrix, is an innovative scaffold for the meniscal regeneration. MSC / MFC combined transplantation with bioactive biodegradable heterogenous decalcified cancellous bone scaffold as a in vivo way to repair meniscal damage of avascular region provides the basis for using combined transplant of MSC and terminal differentiated MFC to repair meniscal damage and also provides the basis for using peripheral blood MSC for meniscal regeneration.

半月板由于血供和力学环境的特殊性，其损伤后的修复一直是运动医学领域的挑战。相比干细胞分化的不可控性，自体半月板纤维软骨细胞 (meniscal fibrochondrocytes, MFC) 认为是半月板再生的最佳种子细胞，但是有限的数量和易出现去分化的现象限制其进一步应用。我们前期的研究发现外周血来源的MSC由于其取材微创、有利于实现自体移植及优良的成软骨潜能用于软骨再生具有非常广阔的临床应用前景。本研究拟建立外周血MSC和MFC的共培养体系，通过外周血MSC的旁分泌和"营养"功能逆转去分化的MFC使其恢复MFC的表型；并进一步探索MFC发生去分化及复分化的机制可能是通过HIF1?转录调控SOX9发挥作用。来源广泛、具有生物活性的异种脱钙松质骨其主要成分是Ⅰ型胶原，与半月板基质成分类似，本研究拟采用其负载MSC/MFC联合移植修复半月板无血供区损伤为临床半月板再生提供参考。

半月板由于血供和力学环境的特殊性，其损伤后的再生一直是运动医学领域的挑战。自体半月板纤维软骨细胞曾一度认为是半月板再生的最佳种子细胞，但是有限的数量和易出现去分化的缺点限制其进一步应用。本课题成功分离并稳定获取具有微创取材、优良的成软骨潜能和自体来源优势的外周血MSC，并从多方面研究其体外生物学特性及其在肌肉骨骼系统组织再生中的应用。建立半月板细胞与外周血MSC体外二维和三维条件下共培养体系，通过外周血MSC的旁分泌和“营养”功能逆转半月板细胞的去分化，并获得最佳的MSC/半月板细胞比例和ECM形成。采用半月板细胞复合支架材料构建组织工程半月板为临床半月板再生提供参考。然而，该共培养体系用于体内半月板再生的研究及最佳的半月板替代支架材料载体还需要进一步探索。