低频电磁场促进骨髓间充质干细胞移植修复大鼠脊髓损伤的实验研究

背景：骨髓间充质干细胞移植治疗脊髓损伤被视为一种有前途的治疗方法,如何更有效地促进骨髓间充质干细胞在脊髓损伤区存活,加速脊髓损伤肢体运动功能的恢复是目前研究的重点。前期研究发现,低频电磁场能够促进骨髓间充质干细胞的增殖分化,低频电磁场是否可应用于骨髓间充质干细胞移植治疗脊髓损伤还需进一步研究。目的：探讨低频电磁场对移植骨髓间充质干细胞脊髓损伤大鼠后肢运动功能恢复的影响。方法：采用脊髓压迫法制备64只T10不完全性脊髓损伤大鼠模型,随机等分为对照组、骨髓间充质干细胞组、电磁场组和电磁场＋骨髓间充质干细胞组。造模成功后,骨髓间充质干细胞组和电磁场＋骨髓间充质干细胞组大鼠脊髓损伤原部位注射大鼠全贴壁法分离培养BrdU标记的骨髓间充质干细胞,对照组和电磁场组注射a-MEM培养液。造模术后24h,电磁场组和电磁场＋骨髓间充质干细胞组予60min/d的低频电磁场刺激（频率50Hz、强度5mT）。结果与结论：骨髓间充质干细胞移植后第21天,电磁场＋骨髓间充质干细胞组BBB评分与其他组相比,差异有显著性意义（P〈0.05）,与其他各组比较,电磁场＋骨髓间充质干细胞组移植细胞后,大鼠BrdU阳性细胞在脊髓损伤区域生长并与脊髓组织融合,存活细胞数量较其他组多;空洞面积小;损伤区胶质纤维酸性蛋白表达更少,而基质金属蛋白2表达更多;脊髓损伤大鼠下肢运动功能恢复最快（P〈0.05）。提示低频电磁场促进了移植骨髓间充质干细胞脊髓损伤大鼠后肢运动功能的恢复,可能与低频电磁场有利于损伤区移植骨髓间充质干细胞的存活,上调基质金属蛋白2的表达并减少胶质瘢痕的形成有关。

Low-frequency electromagnetic fields enhance the recovery of spinal cord injured rats undergoing bone mesenchymal stem cell transplantation

BACKGROUND： Bone marrow mesenchymal stem cell transplantation is considered as a promising therapy for spinal cord injury. How to more effectively promote the survival of bone marrow mesenchymal stem cells in the area of spinal cord injury and to accelerate the recovery of motor function after spinal cord injury is a current study focus. Previous studies have found that low-frequency electromagnetic fields can promote bone marrow mesenchymal stem cell proliferation and differentiation, but whether the low-frequency electromagnetic fields can be applied to bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury requires further studies. OBJECTIVE： To discuss the effects of low-frequency electromagnetic fields on motor function of spinal cord injury rats after transplantation of bone mesenchymal stem cells. METHODS： Sixty-four rat models of incomplete spinal cord injury at T 10 were established by compression method and then randomized into control group, transplantation group （bone mesenchymal stem cell transplantation）,electromagnetic field group and combination group （electromagnetic field＋bone mesenchymal stem cell transplantation）. After successful modeling, bone mesenchymal stem cells labeled with 5-bromo-2＇-deoxyuridine were injected into the original injured site in the transplantation group and combination group, which were isolated and purified with the fast adherence method; while alpha-minimum essential medium was injected into the electromagnetic field group and control group for instead. At 24 hours post-operation, the electromagnetic field group and combination group were explored to low-frequency electromagnetic fields （frequency 50 Hz, magnetic indaction intensity 5 mT） for 60 minutes per day. RESULTS AND CONCLUSION： After cell transplantation for 21 days, the Basso, Beattie, and Bresnahan scores in the combination group was higher than the other groups （P 0.05）. 5-Bromo-2＇-deoxyuridine positive cells grew well, and integrated into the normal spine; syringomyelia was reduced, and the number of spinal neural cells was increased in the combination group. In addition, glial fibrillary acidic protein expression was decreased in the combination group, while matrix metalloproteinase 2 expression was increased. It indicates that low-frequency electromagnetic fields could promote recovery of motor function in the spinal cord injury rats transplanted with bone mesenchymal stem cells, which could be associated that low-frequency electromagnetic fields facilitate the survival of transplanted bone mesenchymal stem cells, up-regulate the expression of matrix metalloproteinase 2, and reduce glial scar formation in the spinal cord injured site.