Programa de Pesquisa em Neurociência Básica e Clínica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Tissue Eng Part A. 2012 Oct;18(19-20):2030-9. doi: 10.1089/ten.TEA.2011.0496. Epub 2012 Jul 9.
Despite the fact that the peripheral nervous system is able to regenerate after traumatic injury, the functional outcomes following damage are limited and poor. Bone marrow mesenchymal stem cells (MSCs) are multipotent cells that have been used in studies of peripheral nerve regeneration and have yielded promising results. The aim of this study was to evaluate sciatic nerve regeneration and neuronal survival in mice after nerve transection followed by MSC treatment into a polycaprolactone (PCL) nerve guide. The left sciatic nerve of C57BL/6 mice was transected and the nerve stumps were placed into a biodegradable PCL tube leaving a 3-mm gap between them; the tube was filled with MSCs obtained from GFP+ animals (MSC-treated group) or with a culture medium (Dulbecco's modified Eagle's medium group). Motor function was analyzed according to the sciatic functional index (SFI). After 6 weeks, animals were euthanized, and the regenerated sciatic nerve, the dorsal root ganglion (DRG), the spinal cord, and the gastrocnemius muscle were collected and processed for light and electron microscopy. A quantitative analysis of regenerated nerves showed a significant increase in the number of myelinated fibers in the group that received, within the nerve guide, stem cells. The number of neurons in the DRG was significantly higher in the MSC-treated group, while there was no difference in the number of motor neurons in the spinal cord. We also found higher values of trophic factors expression in MSC-treated groups, especially a nerve growth factor. The SFI revealed a significant improvement in the MSC-treated group. The gastrocnemius muscle showed an increase in weight and in the levels of creatine phosphokinase enzyme, suggesting an improvement of reinnervation and activity in animals that received MSCs. Immunohistochemistry documented that some GFP+ -transplanted cells assumed a Schwann-cell-like phenotype, as evidenced by their expression of the S-100 protein, a Schwann cell marker. Our findings suggest that using a PCL tube filled with MSCs is a good strategy to improve nerve regeneration after a nerve transection in mice.
尽管周围神经系统在创伤后能够再生，但损伤后的功能结果仍然有限且不佳。骨髓间充质干细胞（MSCs）是多能细胞，已被用于周围神经再生的研究，并取得了有希望的结果。本研究旨在评估神经切断后，将 MSCs 注入聚己内酯（PCL）神经导管中对小鼠坐骨神经再生和神经元存活的影响。将 C57BL/6 小鼠的左侧坐骨神经切断，将神经残端放置在可生物降解的 PCL 管中，使它们之间留有 3mm 的间隙；将 MSC 从 GFP+动物获得的 MSC（MSC 处理组）或培养基（DMEM 组）注入管内。根据坐骨神经功能指数（SFI）分析运动功能。6 周后，处死动物，收集和处理再生坐骨神经、背根神经节（DRG）、脊髓和腓肠肌进行光镜和电镜检查。对再生神经的定量分析显示，在神经导管内接受干细胞的组中，有髓纤维的数量显著增加。MSC 处理组的 DRG 神经元数量显著增加，而脊髓运动神经元数量无差异。我们还发现 MSC 处理组中营养因子表达水平升高，特别是神经生长因子。SFI 显示 MSC 处理组有显著改善。腓肠肌重量增加，肌酸磷酸激酶酶水平升高，提示接受 MSCs 的动物神经再支配和活动改善。免疫组织化学证实，一些 GFP+移植细胞表现出施万细胞样表型，这表现为其 S-100 蛋白的表达，这是施万细胞的标志物。我们的研究结果表明，使用充满 MSCs 的 PCL 管是改善小鼠神经切断后神经再生的一种较好策略。
