神经干细胞移植联合FK506对脊髓损伤病理和超微结构变化的影响

Effects of neural stem cells transplantation and FK506 on pathologic and ultrastructurai changes of injured spinal cord

目的探讨脊髓损伤后神经干细胞（neural stem cells，NSCs）移植对大鼠损伤脊髓病理和超微结构的影响，以及免疫抑制剂他克莫司（FKS06）对神经再生的保护作用。方法采用成年SD大鼠，制作B节段脊髓压迫损伤模型。动物按随机数字表法分为对照组、FKS06组、NSCs组和NSCs＋FKS06组。伤后7，14，28，56d应用运动诱发电位（motor-evoked potential，MEP）监测、HE染色、免疫组织化学染色、超微结构观察及有髓纤维图像分析比较各组神经再生差异。结果伤后28dNSCs＋FKS06组MEP潜伏期与其他各组比较明显缩短（P〈0．05）。HE染色显示，56d时NSCs＋FKS06组只出现灶性坏死。与对照组比较，BrdU和NF-200免疫组织化学染色示各组阳性细胞数增多，且NSCs＋FKS06组阳性细胞数高于其他两组。电镜扫描结果显示，56d时对照组仍可见大的神经髓鞘轴膜下水肿，NSCs＋FKS06组可见典型的新生髓鞘和轴索，神经纤维再生效果均比其他各组好（P〈0．01）。结论脊髓损伤大鼠移植NSCs后，早期联合应用FKS06可改善神经再生纤维的病理和超微结构，具有良好的促神经再生作用。

Objective To investigate the impacts of neural stem cells （NSCs） transplantation on spinal pathology, and ultrastructure after spinal cord injury （SCI） in rats and probe into the protective role of tacrolimus （FKS06） on neural regeneration. Methods Compressive SCI at Ts was induced in the adult SD rats, which were randomly assigned to the control group, FKS06 group, NSCs group and NSCs ＋ FKS06 group. The differences of neural regeneration in each group were compared at days 7, 14, 28 and 56 after injury by motor evoked potentials （MEP）, HE staining, immunohistochemical staining, ul- trastructure observation and image analysis of the myelinated fiber. Results The MEP latency in the NSCs ＋ FKS06 group was significantly shorter than that in other groups at day 28 （ P 〈 0.05 ）. HE stai- ning revealed that only local necrosis presented in the NSCs ＋ FKS06 group at day 56. More BrdU and NF-200 positive cells were detected with immunohistochemical staining in the other three groups as com- pared with the control group. Moreover, the positive cells in the NSCs ＋ FKS06 group also outnumbered the FKS06 group and NSCs group. Electron microscope scan showed edema under the membrane of large myelin sheath in the control group, and classic new myelin sheath and neuraxis in the NSCs ＋ FKS06 group at day 56. The regeneration of the nerve fiber in the NSCs ＋ FKS06 group was better than that ofother three groups （ P 〈 0.01 ）. Conclusion After NSCs transplantation for SCI rats, the early combi- nation use of FK506 can improve the pathology and ultrastructure of the regenerative nerve fiber and is conducive to nerve regeneration.