Abstract: 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) Hematoxylin-eosin 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. 

Key words: spinal cord, material, nanofiber, spinal cord injury, tissue engineering, nano scaffold, experiment, rat