脱细胞异种神经移植体复合BMSCs修复大鼠坐骨神经缺损的研究

EXPERIMENTAL SCIATIC NERVE REPAIRED BY ACELLULAR NERVE XENOGRAFTS LMPLANTED WITH BMSCS IN RATS

目的:对脱细胞异种神经的生物相容性进行评价,证明应用其复合BMSCs促进神经再生和功能恢复的效果。方法:采用化学萃取法制备兔的脱细胞神经,应用扫描电镜观察其超微结构;将BMSCs种植到神经支架构建神经移植体,体外培养后观察细胞形态;用构建的异种神经移植体桥接大鼠坐骨神经缺损,术后8周,检测胫前肌湿重比率,对再生神经进行组织形态学分析;并应用免疫荧光染色检测神经内NGF的表达。结果:脱细胞异种神经较完整地保留了天然立体的施万细胞基底膜管结构,完全地移除了神经内的施万细胞、轴突和髓鞘成分;在体外培养中支持种植的BMSCs黏附和生长。神经移植术后,与单纯异种脱细胞神经移植组相比,复合BMSCs的异种神经移植体移植能使胫前肌湿重比率增加、有髓神经纤维数目、髓鞘厚度和轴突直径增加;增加再生神经内NGF的表达。结论:异种脱细胞神经移植体具备天然的立体结构,移除了施万细胞、髓鞘等抗原成分;神经支架无细胞毒性,具有良好的细胞相容性;复合BMSCs的异种神经移植体可显著地促进神经再生及功能恢复。

Objective：To evaluate the biocompatibility of acellular nerve xenografts , after bridging nerve gaps by utilizing the BM-SCs-combined xenogenic nerve grafts , the effectiveness of axonal regeneration and functional restoration was demonstrated .Methods：The acellular nerves derived from rabbits through chemically extracted processing were prepared and the ultrastructural organization was subsequently observed using the SEM .The nerve scaffolds were also seeded with BMSCs to construct tissue engineered transplants , af-ter culture in vitro , the ultrastructure of the integrated nerve grafts was observed .And then the xenogenic nerve grafts were employed to bridge sciatic nerve gaps in rats .After 8 weeks post-transplantation , the weight ratios of tibialis anterior muscle were detected , be-sides, the morphological analysis was conducted , and the expression of NGF in the regenerated nerves was carried out via immunostain -ing.Results：The tridimensional architecture of basal lamina tube in extracellular matrix was preserved intactly , and the Schwann cells, axons as well as myelin sheath were removed completely in the acellular nerves .In vitro the nerve grafts exhibited the effects on supporting cells adhesion and growth .After nerve grafting , compared with acellular nerve blank control group , the xenogenic nerve transplantation integrating with BMSCs increased the weight ratios of tibialis anterior muscle , myelinated fiber number , axon diameter and myelin sheath thickness .Moreover, the expression of NGF in regenerated nerves is elevated apparently .Conclusion： The tridi-mensional architecture of basal lamina tube in extracellular matrix is preserved intactly , and the Schwann cells as well as myelin sheath are removed completely in the acellular nerve xenografts .The acellular nerve grafts do not show cytotoxicity , but possess favourable cell compatibility.Nerve regeneration and functional rehabilitation are advanced significantly for xenogenic nerve transplantation integrating with BMSCs .