神经干细胞与原浆型星形胶质细胞联合移植对大鼠脊髓半切空洞损伤的修复作用

Combined transplantation of neural stem cell and protoplasmic astrocyte in the treatment of spinal cord injury following the semi-cut cavity in rats

目的观察神经干细胞（NSC）与原浆型星形胶质细胞（PAS）联合移植对大鼠损伤脊髓功能和形态的修复作用。方法60只Wistar大鼠，制成脊髓L1～L2左侧半切空洞损伤模型，采用随机数字表法分为损伤组（A组）、损伤后移植PAS组（B组）、移植NSC组（C组）、NSC和PAS按2：1比例联合移植组（D组），每组15只。伤后1，4，8周进行伤侧下肢BBB评分、体感诱发电位（SEP）和运动诱发电位（MEP）检测；8周损伤部位脊髓组织进行HE、Nissl、Holmes银染，观察移植物在损伤脊髓中的形态学变化。结果（1）行为学观察：4周时，各组间开始出现差异；8周时，组间差异更为明显，尤其D组大鼠最明显，已能行走，行走时频繁足底离地，并能与前后肢体协调运动，B、C组功能有一定改善，可支重性足底踏步，前后肢共济协调，但仍和D组存在明显差距，A组后肢关节活动幅度增加，足底仍不能着地支重。（2）电生理检查：1周时，各组MEP峰潜时（以NI波计算）和SEP峰潜时（以P1波计算）开始出现差异，至4，8周，B、C、D组峰潜时明显缩短，但D组缩短最为显著（P〈0．01）。（3）病理观察：8周时，A组缺损严重，新生组织较少，B、C、D组缺损组织基本填补完全，损伤空洞闭合，未见明显的炎症反应，B组损伤处可见大量形态不同、大小不等的新生胶质细胞，胶质纤维排列紊乱，病理染色未见神经元；C组损伤处新生组织较多，以神经胶质细胞为主，少量神经元分布，且可见再生纤维连接；D组损伤处新生组织填补缺损完全，胶质纤维中可见形态典型的新生神经元，数量明显多于C组。结论NSC和PAS联合移植到损伤脊髓组织后，能够存活、分化并从结构和功能上较好地修复组织缺损区域。

Objective To observe the morphological and functional recovery of rat spinal cord after transplantation of neural stern cell （NSC） and protoplasmic astrocyte （PAS）. Methods Sixty Wistar rats, which were injured on the left side of L1 -L2 spinal cord, were randomly divided into injury group （Group A） , PAS transplantation group （Group B） , NSC transplantation group （Group C） , combined PAS and NSC transplantation group （Group D, NSC ：PAS = 2：1 ） , 15 rats in each group. The BBB scale, motor evoked potential （MEP） and somatosensory evoked potential （SEP） of lower limb were examined at 1, 4 and 8 weeks after injury. The injured spinal cords were stained by hematoxylin-eosin, Nissl and Holmes to observe the morphological changes of transplants at eight weeks after injury. Results （ 1 ） There was significant difference in behavior among groups at four weeks after injury. At eight weeks after injury, the hindlimb in Group D could support body weight, and forelimb could collaborate with hindlimb during movement. There were certain improvements of the behavior of rats in Groups B and C. The active extent of the hindlimb was improved, but the hindlimb still could not support body weight. There was significant difference among four groups. （2） At one week after injury, sensory and motor functions in all groups were rehabilitated differently. At four and eight weeks after injury, the latencies of peak N1 and P1 became shorter in Groups B, C and D, especially Group D （P 〈0.01 ）. （3） At eight weeks after injury, the injury in Group A was much severe, with few cambiums. The cavity was basically closed in Groups B, C and D, with no obvious inflammation. Lots of diversified regenerative astrocytes were observed in Group B, and the gelatinous fibers were disorderly arrayed. No neuron was observed in Group B. Lots of cambiums （mainly astrocytes） and a few neurons could be seen in Group C, with the regenerated fibers connected. The cavity was fully closed in Group D, with more regenerative neurons with dendrites than in Group C. Conclusions NSC and PAS can not only survive and differentiate when they are transplanted to the injured spinal cord, but also repair the injured area in terms of structure and function.