Division of Plastic Surgery, University of Alberta, Edmonton, AB, Canada.
Exp Neurol. 2011 Apr;228(2):242-52. doi: 10.1016/j.expneurol.2011.01.013. Epub 2011 Jan 31.
Mesenchymal stem cells (MSCs) support axon regeneration across artificial nerve bridges but their differentiative capacity and ability to promote nerve regeneration remains unclear. In this study, MSCs isolated from bone marrow of Sprague-Dawley rats were characterized by plastic adherence and pluripotency towards mesodermal lineages. Isolated undifferentiated MSCs (uMSCs) were stimulated towards a Schwann cell (SC) phenotype using specific growth factors, and cell marker analysis was performed to verify SC phenotype in vitro. Differentiation resulted in temporally dependent positive immunocytochemical staining for the SC markers, glial fibrillary acidic protein (GFAP), S100, and nerve growth factor receptor (NGFR), with maximal marker expression achieved after 6days of treatment with differentiation media. Quantitative analysis demonstrated that ~50% of differentiated MSCs (dMSCs) have a SC phenotype. Using an indirect co-culture system, we compared the ability of dorsal root ganglion (DRG) cells to extend neurites in indirect contact with uMSCs and dMSCs as compared to SCs. The mean values of the longest length of the DRG neurites were the same for the dMSCs and SCs and significantly higher than the uMSC and DRG mono-culture systems (p < 0.05). In vivo, compared to an empty conduit, dMSC seeded collagen nerve conduits resulted in a greater number of sciatic motoneurons regenerating axons through the conduit into the distal nerve stump. We conclude that bone marrow-derived MSCs differentiate into a SC-phenotype that expresses SC markers transiently and sufficiently to support limited neurite outgrowth in vitro and axonal regeneration equivalent to that of SCs in vitro and in vivo. The nerve autograft remains the most effective conduit for supporting regeneration across nerve gaps.
间充质干细胞（MSCs）支持穿过人工神经桥的轴突再生，但它们的分化能力和促进神经再生的能力仍不清楚。在这项研究中，从 Sprague-Dawley 大鼠骨髓中分离的 MSCs 通过塑料附着和向中胚层谱系的多能性来表征。分离的未分化 MSCs（uMSCs）使用特定的生长因子刺激向施万细胞（SC）表型分化，并进行细胞标志物分析以体外验证 SC 表型。分化导致 SC 标志物神经生长因子受体（NGFR）、神经胶质纤维酸性蛋白（GFAP）和 S100 的免疫细胞化学染色呈时间依赖性阳性，在用分化培养基处理 6 天后达到最大标志物表达。定量分析表明，约 50%的分化 MSC（dMSC）具有 SC 表型。在间接共培养系统中，我们比较了与 uMSC 和 dMSC 间接接触的背根神经节（DRG）细胞在间接接触中延伸神经突的能力，与 SC 相比。DRG 神经突最长长度的平均值在 dMSC 和 SC 中相同，明显高于 uMSC 和 DRG 单核培养系统（p<0.05）。在体内，与空导管相比，dMSC 接种胶原神经导管导致更多的坐骨运动神经元通过导管再生轴突进入远端神经残端。我们得出结论，骨髓来源的 MSCs 分化为 SC 表型，短暂且充分地表达 SC 标志物，以支持体外有限的神经突生长和体外和体内与 SC 相当的轴突再生。神经自体移植物仍然是支持神经间隙再生的最有效导管。
