纳米组织工程化脊髓修复脊髓损伤

Spinal cord injury repaired by using nano tissue-engineered spinal cord

背景:应用组织工程修复脊髓损伤是近年来的研究热点,多数研究仍停留在体外实验阶段。目的:将新型胶原纳米纤维膜与神经干细胞复合构建组织工程化脊髓,探寻其修复脊髓损伤的效果。方法:以胶原为原料,应用电子纺丝技术制备纤维平行排列及交错排列的纳米纤维膜;将新生大鼠脊髓源性神经干细胞分别接种于两种纳米纤维上培养7 d,构建组织工程化脊髓。建立SD大鼠脊髓半横断动物模型,随机分5组干预:空白对照组未植入任何材料;平行组织工程组与交错组织工程组植入对应的组织工程化脊髓,交错组与平行组植入对应排列的纳米纤维膜。术后1-8周进行改良行为学BBB评分;术后8周取术区脊髓组织,进行苏木精-伊红染色与免疫组化染色。实验获得哈尔滨医科大学实验动物福利和伦理管理委员会批准。结果与结论:①平行组织工程组术后各时间点的改良行为学BBB评分均高于其余4组(P <0.05),交错组织工程组、平行组、交错组各时间点的评分高于空白对照组(P <0.05),交错组织工程组术后2-8周的评分高于平行组、交错组(P <0.05),平行组术后1,2周的评分高于交错组(P <0.05);②苏木精-伊红染色显示,空白对照的损伤区域几乎无细胞结构,可见大量瘢痕组织形成;平行组、交错组抑制了瘢痕组织形成,组织修复不明显,邻近组织瘢痕形成,损伤区与周围未建立细胞联系;两组织工程组支架降解区域内有大量细胞成分,局部有较多组织再生,细胞数量较多,细胞沿支架方向分布,彼此相关并与正常组织相连;③免疫组化染色显示,两组织工程组可见神经元细胞;④结果表明,纳米组织工程化脊髓修复脊髓损伤的效果良好,以平行纳米纤维膜构建的组织工程化脊髓修复效果更佳。

BACKGROUND: The application of tissue engineering in the repair of spinal cord injury is a focus of research in recent years, and most of the studies are still in vitro stage. OBJECTIVE: To explore the effect of repairing spinal cord injury with tissue-engineered spinal cord that was composed of new collagen nanofiber membrane and neural stem cells.METHODS: Collagen was used as raw material, and the nanofiber membrane with parallel arrangement and staggered arrangement of fibers was prepared by electronic spinning technology. The spinal cord derived neural stem cells of neonate rats were cultured on two kinds of nanofibers for 7 days to construct the tissue-engineered spinal cord. Sprague-Dawley rat models of spinal cord hemisection were randomly divided into five groups. In the blank control group, any material was not used. In the parallel tissue engineering group and cross tissue engineering group, corresponding tissue-engineered spinal cord was used. In the parallel group and cross group, corresponding nanofiber membrane was used. At 1-8 weeks after the operation, modified BBB scores of the rats were recorded. At 8 weeks after operation, the spinal cord was taken and stained with hematoxylin and eosin and received immunohistochemistry. The experiments were approved by experimental animal welfare and Ethics Management Committee of Harbin Medical University.RESULTS AND CONCLUSION:(1) The BBB scores in the parallel tissue engineering group were higher than those in the other four groups(P < 0.05). The BBB scores in the staggered tissue engineering group, the parallel group and the staggered group were all higher than those in the blank control group(P < 0.05). The BBB scores in the staggered tissue engineering group were higher than those in the parallel group and the staggered group at 2-8 weeks after operation(P < 0.05). The BBB scores in the parallel group were higher than those in the staggered group at 1 and 2 weeks after operation(P < 0.05).(2) Hematoxylineosin staining showed that there was almost no cell structure in the injury area of the blank control, and a large number of scar tissue formation was seen. The formation of scar tissue was inhibited in the parallel group and the staggered group, and the tissue repair was not obvious;the scar formation in the adjacent tissue and no cell connection was established between the injury area and the surrounding area. There were a large number of cell components in the scaffold degradation area of the two tissue engineering groups, and there were obvious tissue regeneration, more cells distributed along the direction of the scaffold;connections were built among the cells and with normal tissues.(3) Immunohistochemistry staining showed that neurons were seen in the two tissue engineering groups.(4) The results showed that the effect of nano tissue engineering on the repair of spinal cord injury was good, and the effect of parallel nano fiber membrane was better.