小肠黏膜下层复合雪旺细胞构建组织工程化人工神经修复周围神经缺损的研究

The study of construction of tissue-engineered artificial nerve with small intestinal submucosa compound of Schwann cells to repair peripheral nerve defect

目的小肠黏膜下层（small intestinal submucosa，SIS）复合雪旺细胞构建组织工程化人工神经并探讨其修复周围神经缺损的效果。方法SD大鼠60只随机分成三组，每组20只。构建右侧坐骨神经14mm缺损，A组：单纯SIS修复组；B组：复合雪旺细胞的SIS修复组；C组：自体神经移植对照组。术后不同时间段通过大体观察、电生理检测、组织学、透射电镜、图像分析、逆行示踪和小腿三头肌称重等方法分析评价修复效果。结果术后16周，B组移植段与近远段神经外观相似，未有神经瘤形成。组织学和透射电镜检查见B组再生神经组织可顺利通过缺损区，再生神经纤维排列整齐呈束状，含有大量的有髓神经纤维，与C组相似。电生理检测见第16周B组神经传导速度和复合动作电位的波幅均较第12周有所提高，与C组相比差异无统计学意义。真蓝逆行示踪证实B组和C组再生神经轴突轴浆运输功能恢复良好。图像分析证实B组再生神经组织面积百分比、有髓神经纤维密度和髓鞘厚度与C组相比差异无统计学意义，优于A组。B组和C组患侧小腿三头肌肌肉重量和恢复率均优于A组，C组优于B组，且差异有统计学意义。结论SIS复合雪旺细胞构建组织工程化人工神经能有效修复大鼠长距离坐骨神经缺损，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 construct the tissue-engineered artificial nerve with small intestinal submucosa （SIS） compound of Schwann cells （SCs） and explore the effects of repair peripheral nerve defect. Methods Sixty SD rats were divided into three groups randomly. A 14 mm defect of right sciatic nerve was made. Group A： SIS repairing group; Group B： SIS compound of SCs repairing group; Group C＇. auto-nerve grafting contrast group. The repairing results were evaluated after operation at different times by gross observation, electrophysiology, histology, transmission electron microscope, image analysis, retrograde tracing and triceps muscle of calf weighing. Results At 16 weeks after operation, the graft appearance was similar to the proximal and distal nerve without neuroma formation in group B. Histology and transmission electron mi- croscope examination showed regenerative nerve tissue grew through the defect successfully, the regenerative nerve fibers arranged in bundles orderly, containing a great quantity of myelined nerve fibers in group B, which was similar to group C. Electrophysiology detection showed the nerve conduction velocity and ampli- tude of compound action potential of group B at 16 weeks was greater than at 12 weeks. There was no statistical significant difference when compared to group C. The true blue retrograde tracing demonstrated axonal axoplasmic transport of regenerative nerve recovered well in group B and group C. Image analysis confirmed there was no statistical significant difference of percentage of regenerative nerve tissue, density of myelined nerve fibers and thickness of myelin between group B and group C, both were better than group A. The weight of triceps muscle of calf and recovery rate in group B and group C were better than group A, and group C was better than group B. Conclusion The tissue-engineered artificial nerve constructed with SIS compound of SCs can repair long sciatic nerve defect effectively in rats. It is promising to be applied in repairing long peripheral nerve defect.