Hematopoietic stem cell and bone marrow stromal cell for treatment of spinal cord injury.

目的：比较造血干细胞(HSC)和骨髓基质细胞(BMSC)移植治疗脊髓损伤的效果。材料和方法：(实验1)从绿色荧光蛋白(GFP)转基因小鼠骨髓中，用流式细胞仪分选出谱系阴性、c-kit和SEA-1阳性的细胞，作为HSC和BMSC培养的贴壁细胞。用静态载荷(20g，5min)致C57BL/6小鼠脊髓损伤。伤后1周，将HSC或BMSC注入损伤区。观察功能恢复情况，并进行免疫组织化学染色。(实验2)从成人患者骨髓培养人骨髓基质细胞(HBMSC)，用磁激活细胞分选法(HUCB)收集人脐血中的人造血干细胞。雄性Wistar大鼠切断椎板，用NYU冲击器(10g，25 mm)挫伤脊髓。伤后第9天，将hBMSC或HUCB注入损伤区。结果：(实验1)HSC组部分GFP阳性细胞表达胶质细胞标志物。骨髓间充质干细胞组可见大量绿色荧光蛋白和纤维连接蛋白双阳性细胞。两组痊愈情况无明显差异。(实验2)hBMSC和HUCB均可缩小病变中心囊腔面积，促进酪氨酸羟基酶和5-羟色胺阳性神经纤维的轴突再生，移植后5周，hBMSC在损伤脊髓内存活较少，而HUCB无存活。HBMSC组和HUCB组后肢功能均有明显恢复。结论：HSC和BMSC均有修复损伤脊髓、促进功能恢复的作用。

Objective : The aim of the present study was to compare effects of hematopoietic stem cells (HSC) and bone marrow stromal cells (BMSC) transplantation for spinal cord injury.Materials and Methods : (experiment 1) From green fluorescent protein (GFP) transgenic mouse bone marrow, lineage-negative, c-kit- and Sea-1-positive cells were sorted by FACS as HSC and plastic-adherent cells were cultured as BMSC. Spinal cords of C57BL/6 mice were injured with static load (20g, 5min). One week after injury, HSC or BMSC were injected into the lesioned site. Functional recovery was assessed and immunohistochemistry was performed. (experiment 2) Human bone marrow stromal cells (hBMSC) were cultured from bone marrow of adult human patient and human hematopoietic stem cells were collected from human umbilical cord blood using magnetic activated cell sorting (HUCB). Male Wistar rats were laminectomized and their spinal cords were contused using NYU impactor (10g,25mm). Nine days after injury, hBMSC or HUCB was injected into the lesioned site. Histological examination, immunohistochemistry, electron microscopy and functional assessment were performed.Results : (experiment 1) In the HSC group, a portion of GFP-positive cells expressed glial marker. In the BMSC group, a number of GFP- and fibronectin-double positive cells were observed. There was no significant difference in the recovery between both groups. (experiment 2) Both hBMSC and HUCB reduced area of cystic cavity in the lesion epicenter and promoted axonal regeneration of tyrosine hydroxylase- and serotonin-positive nerve fibers.Five weeks after transplantation, a small number of hBMSC survived in injured spinal cord, whereas no HUCB survived. Hind limb function significantly recovered in both the hBMSC and HUCB groups.Conclusion : Both HSC and BMSC have potential to restore injured spinal cord and to promote functional recovery.