神经干细胞对脊髓前角运动神经元保护作用的实验研究

目的观察臂丛根性撕脱伤后神经干细胞脊髓内移植对前角运动神经元的保护作用。方法取孕龄15～18d胎鼠脑组织，分离获得神经干细胞，在体外培养、扩增，并用5溴-2脱氧尿苷(BrdU)标记。取Wistar大鼠72只，随机分成实验组与对照组。先将C5～T1神经根撕脱，实验组把体外培养的神经干细胞移植于C5～T1脊髓节段前角附近，而对照组则用缓冲液替代神经干细胞。术后1、2、4、6、8、12周取脊髓标本进行组织学与免疫组化染色观察。结果臂丛根性撕脱伤后脊髓前角运动神经元数目明显减少，到术后12周时，对照组运动神经元减少达80．3％，实验组达63．7％。并且，各时间点实验组运动神经元的存活率均高于对照组。实验组脊髓前角内可见散在但仍保持未分化特征的神经干细胞。结论神经干细胞在植入臂丛根性撕脱伤的脊髓后能存活，并能明显减少前角运动神经元的继发性死亡。

An experimental study on protective effect of neural stem cells on motoneurons in ventral horn of spinal cord

Objective To investigate the protective effect of transplantation of neural stem cells into spinal cord on the survival of motoneurons after brachial plexus root avulsion injury. Methods Neural stem cells were isolated from the brain tissue of fetal rats (P15-18) and cultured,expanded in vitro, marked by BrdU. Seventy-two adult Wistar rats were randomly divided into experimental and control group. The roots of C 5-T 1 were selectively avulsed from the spinal cord. In the experimental group, the neural stem cells cultured in vitro were transplanted into the C 5-T 1 spinal cord nearby the ventral horn. In the control group, the buffer was transplanted instead. On 1,2,4,6,8,12 weeks postoperatively, histology immunohistochemistry assay were carried out in the spinal cord.Results The number of motoneurons in the ventral horn of spinal horn decreased markedly. On 12 weeks postoperatively, the number of lost motoneurons in control group and in experimental group reached 80.3% and 63.7% respectively. The survival rate of motoneurons in the experimental group was higher than that in the control group at all time points. Immunohistochemistry assay showed nondifferentiated neural stem cells scattered in the ventral horn of spinal cord in the experimental group. Conclusion The neural stem cells can survive in the spinal cord after transplantation in patients with brachial plexus root avulsion injury, and can obviously decrease the secondary necrosis of motoneurons of the ventral horn.