几丁糖复合聚乙烯醇神经导管修复大鼠坐骨神经缺损

Chitosan/PVA nerve conduits repair sciatic nerve defect in rats

目的探讨应用几丁糖复合聚乙烯醇神经导管，修复大鼠周围神经缺损的效果。方法选取健康sD大鼠27只，随机分成3组，每组9只。分别用几丁糖复合聚乙烯醇神经导管桥接、硅胶管和自体神经逆行原位移植修复大鼠坐骨神经15mm缺损。在术后12周进行大体观察、肌肉湿重和肌纤维横截面积、组织学观察和神经示踪检查评价神经再生。结果术后12周时：A组再生神经已通过1．5cm的缺损且再生神经直径较粗，达到正常神经的直径。肌肉湿重和肌细胞截面积：A组和C组比较．差异无统计学意义（P〉0．05）；A、C组明显优于B组，差异有统计学意义（P〈0．05）。组织学观察：A组和C组神经纤维数目多、大小均匀、成熟良好，B组神经纤维数目少、不均匀、髓鞘发育较差。神经示踪观察结果显示：A、B、C三组在L4～L6节段脊髓前角和背根节均可见到真蓝标记的神经元细胞，其中A组脊髓前角真蓝标记的神经元数目和C组相似，差异无统计学意义（P〉0．05），但明显优于B组，差异有统计学意义（P〈0．05）。结论几丁糖复合聚乙烯醇神经导管具有促进神经轴突再生的作用．有望成为自体神经的替代材料，应用于周围神经缺损的修复。

Objective To investigate the effects of chitosan/PVA nerve conduits which used for re- pairing sciatics nerve defect in rats. Methods Twenty-seven rats were divided into 3 groups randomly, with 9 rats in each group. Firstly, the 15mm defects in the left sciatic nerves were made in the rats and were respectively repaired with ehitosan/PVA conduits graft （group A）, the silicon conduits graft （group B）, and autografts （group C）. At 12 weeks after the operations, the left sciatic nerves were taken out, and the com- parative evaluation was made on the repairing effects by wet weight of gastrocnemius and soleus muscles, histo- logical examination, computerized imaging analysis and True Blue retrograde tracing. Results The wet weight of gastrocnemius and soleus muscles showed no significant difference between the chitosan/PVA graft and autograft groups （P 〉 0.05）. The wet weight of gastrocnemius and soleus muscles in significant difference between the chitosan/PVA graft and the silicon group at 12 weeks after the operation（P 〈 0.05）. The nerve fiber density showed no statistically significant differences between the ehitosan/PVA and autograft groups （P 〉 0.05）. The regenerative nerve fiber in group B had normal morphological and structural characters under transmission electron microscope. True Blue-labeled neuron cell bodies were found within both anterior horn of gray matter in the spinal cord and dorsal root ganglions （DRGs） ipsilateral to the operated side of the test- ed rats on illumination with ultra-violet light 1 week after the injection of True Blue. Conclusion Chi- tosan/PVA nerve conduit can effectively promote the nerve regeneration and myelinization of rat sciatic nerve, which is expected to substitute for autograft to repair nerve defects suceesfully.