中文摘要：

目的 研究天然有序胶原支架联合具有胶原靶向结合域（CBD）的神经营养因子3（NT3）（CBD-NT3）对背根节细胞（DRGs）突起延伸的影响，探讨这种联合策略对脊髓损伤修复的意义。方法将SD大鼠尾肌腱行去细胞处理制备胶原支架，HE染色评价支架的处理效果；去细胞处理后支架负载CBD-NT3并与SD大鼠原代DRGs体外共培养1、3、5d．同时设NT3、PBS组作对照：FDA染色观察共培养后DRGs并定量分析各组细胞突起的长度及角度；扫描电镜观察共培养3d后支架和DRGs的超微结构。结果HE染色显示经处理后支架内细胞成分基本去除；共培养3d后CBD-NT3组DRGs突起延伸长度最长，与NT3组和PBS组比较差异均有统计学意义（P＜0．05）；细胞突起总体延伸方向与支架纤维长轴夹角的双侧95％可信区间为（18．8-20．7）°；扫描电镜显示DRGs能依靠胶原支架表面地貌锚定和生长。结论有序胶原支架联合CBD—NT3能定向引导并促进细胞突起延伸。为脊髓损伤修复的研究提供了一种有效的途径。

英文摘要：

Objective To investigate the effect of collagen scaffold loaded with collagen-binding domain neurotrophin-3 （CBD-NT3） on the extension of cellular processes of dorsal root ganglions （DRGs）, and explore the significance of this kind of combinatorial strategies in the spinal cord injury repair. Methods The tail tendons of SD neonatal rats were performed the removal of cellular components to prepare the collagen scaffold; HE staining was employed to evaluate whether the cells were completely removed from the collagen scaffold. The collagen scaffold was loaded with CBD-NT3, and then, they were co-cultured with primary DRGs for 1, 3 and 5 d, respectively. NT3 and PBS were also co-cultured with primary DRGs for 1, 3 and 5 d, respectively, as controls. Cells on the scaffold were stained by fluorescein diacetate （FDA） for morphology observation and the lengths and angles of the processes in each group were also quantitatively analyzed. Scanning electron microcopy （SEM） was employed to observe the topography of scaffold and the ultrastructure of DRGs 3 d after the co-culture. Results HE staining indicated that the cellular components in the scaffold were removed completely. The length of processes elongation in CBD-NT3 treatment group was significantly longer than that in the controls 3 d after the co-culture （P〈0.05）. The 95% confidence interval of the angle between the line which the process emerged from the cell soma to the growing tip of the process and the long axis of fiber was 18.8-20.7 degrees. The results of SEM showed that cells could rely on the topography of the scaffold to anchor and grow. Conclusion The combinatorial strategies of collagen scaffold with CBD-NT3 can play a double function for oriented guiding and inducing extension of cellular processes effectively, which may provide a better therapeutic approach for spinal cord injury repair.