周围神经移植修复大鼠陈旧性脊髓损伤的实验研究

目的：探讨利用自体周围神经组织游离移植修复大鼠陈旧性脊髓损伤病理机制。方法：利用改良Allen撞击方法建立脊髓打击损伤模型后，将大鼠分为2组，各20只。神经移植组切取后肢腓肠神经，利用显微外科技术去除神经外膜，将其修剪成小段，游离移植于脊髓损伤处，对照组不作处理。分别于术后4、12周，在光镜下观察脊髓损伤段及移植周围神经再生情况，并应用辣根过氧化物酶神经逆行示踪技术进行脊髓神经束的再生评价。分3个时点（1、2、3个月）观察大鼠后肢运动功能恢复情况。结果：对照组脊髓变性，可见瘢痕和空洞，移植组术后12周，损伤区脊髓与周围神经融合良好，可见再生轴突，跨越损伤段脊髓，周围神经无变性。12周时脊髓神经束的再生评价结果提示：神经移植组优于对照组．移植组大鼠后肢运动功能明显恢复。结论：周围神经组织游离移植修复大鼠陈旧性脊髓损伤后，存活良好并可促进大鼠脊髓结构和功能的恢复。

Experimental study of peripheral nerve grafts for repairing of chronic spinal cord injury in adult rats

Objective: To explore the pathological mechanism in the repair of chronic spinal cord injury with free grafting of autoperipheral nerve tissues in rats. Methods: The SD rats were used to establish SCI model with modified Allen method. The rats were divided into two groups at 12 weeks after the injury,each group had 20 rats. In the experimental group,the sural nerves were removed epineurium and transplanted into SCI lesion by using microsurgical technique;and in the control group,the rats were treated without any operation. The survival and differentiation of the grafts,and the ability of repairing host spinal cord were observed under the light microscope at the postoperative 4th and 12th week. Regeneration rates of nerve tracts in spinal cord were evaluated by using HRP tracing technique at the postoperative 4th and 12th week. The morphological changes were observed at section of spinal cord and the motor functions of both hind legs of rats were detected. Results: In the control group,spinal cord exhibited degeneration with cicatrices and cavitates. In the experimental group,peripheral nerve was almost survived,fused with the spinal tissue and axons could regrow into or span the place of injured spinal cord. Higher number of labeled nerve tracts in spinal cord were observed in experimental group,there was significant difference when compared with the control group. Motor function of hind legs of rats recovered significantly in the treatment group. Conclusion: Autoperipheral nerve graft tissues transplantation could survive and integrate with the host and have repairing effects on chronic spinal cord injury in rats.