Barakat D J, Gaglani S M, Neravetla S R, Sanchez A R, Andrade C M, Pressman Y, Puzis R, Garg M S, Bunge M B, Pearse D D
The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
Cell Transplant. 2005;14(4):225-40. doi: 10.3727/000000005783983106.
Due to an ever-growing population of individuals with chronic spinal cord injury, there is a need for experimental models to translate efficacious regenerative and reparative acute therapies to chronic injury application. The present study assessed the ability of fluid grafts of either Schwann cells (SCs) or olfactory ensheathing glia (OEG) to facilitate the growth of supraspinal and afferent axons and promote restitution of hind limb function after transplantation into a 2-month-old, moderate, thoracic (T8) contusion in the rat. The use of cultured glial cells, transduced with lentiviral vectors encoding enhanced green fluorescent protein (EGFP), permitted long-term tracking of the cells following spinal cord transplantation to examine their survival, migration, and axonal association. At 3 months following grafting of 2 million SCs or OEG in 6 microl of DMEM/F12 medium into the injury site, stereological quantification of the three-dimensional reconstructed spinal cords revealed that an average of 17.1 +/- 6.8% of the SCs and 2.3 +/- 1.4% of the OEG survived from the number transplanted. In the OEG grafted spinal cord, a limited number of glia were unable to prevent central cavitation and were found in patches around the cavity rim. The transplanted SCs, however, formed a substantive graft within the injury site capable of supporting the ingrowth of numerous, densely packed neurofilament-positive axons. The SC grafts were able to support growth of both ascending calcitonin gene-related peptide (CGRP)-positive and supraspinal serotonergic axons and, although no biotinylated dextran amine (BDA)-traced corticospinal axons were present within the center of the grafts, the SC transplants significantly increased corticospinal axon numbers immediately rostral to the injury-graft site compared with injury-only controls. Moreover, SC grafted animals demonstrated modest, though significant, improvements in open field locomotion and exhibited less foot position errors (base of support and foot rotation). Whereas these results demonstrate that SC grafts survive, support axon growth, and can improve functional outcome after chronic contusive spinal cord injury, further development of OEG grafting procedures in this model and putative combination strategies with SC grafts need to be further explored to produce substantial improvements in axon growth and function.
由于慢性脊髓损伤患者的数量不断增加，需要实验模型将有效的再生和修复性急性疗法转化应用于慢性损伤。本研究评估了雪旺细胞（SCs）或嗅鞘胶质细胞（OEG）的液体移植物在移植到2个月大的大鼠中度胸段（T8）挫伤模型后，促进脊髓上和传入轴突生长以及促进后肢功能恢复的能力。使用经编码增强型绿色荧光蛋白（EGFP）的慢病毒载体转导的培养胶质细胞，能够在脊髓移植后长期追踪这些细胞，以检查它们的存活、迁移和轴突关联情况。在将200万个SCs或OEG接种于6微升DMEM/F12培养基并移植到损伤部位3个月后，对三维重建脊髓进行体视学定量分析发现，移植的SCs平均有17.1±6.8%存活，OEG平均有2.3±1.4%存活。在OEG移植的脊髓中，少数胶质细胞无法阻止中央空洞形成，且在空洞边缘呈斑块状分布。然而，移植的SCs在损伤部位形成了实质性移植物，能够支持大量密集排列的神经丝阳性轴突向内生长。SCs移植物能够支持降钙素基因相关肽（CGRP）阳性的上行轴突和脊髓上5-羟色胺能轴突的生长，尽管移植物中心没有生物素化葡聚糖胺（BDA）标记的皮质脊髓轴突，但与仅损伤对照组相比，SCs移植显著增加了损伤-移植物部位头端紧邻处的皮质脊髓轴突数量。此外，接受SCs移植的动物在旷场运动中表现出适度但显著的改善，足部位置错误（支撑基底和足部旋转）减少。虽然这些结果表明SCs移植物能够存活、支持轴突生长并可改善慢性挫伤性脊髓损伤后的功能结局，但在该模型中进一步开发OEG移植程序以及与SCs移植物的假定联合策略，以在轴突生长和功能方面取得实质性改善仍需进一步探索。
