Effect of collagenscaffold loaded with collagen-targeting neurotrophin-3 on the extension of cellularprocesses of dorsal root ganglion

：Objective To investigatethe effect of collagen scaffold loaded with collagen-binding domain neurotrophin-3(CBD-NT3) on the extension of cellular processes of dorsal root ganglions (DRGs), andexplore the significance of this kind of combinatorial strategies in the spinal cordinjury repair. Methods The tail tendons of SD neonatal rats were performed the removal ofcellular components to prepare the collagen scaffold; HE staining was employed to evaluatewhether the cells were completely removed from the collagen scaffold. The collagenscaffold 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 and5 d, respectively, as controls. Cells on the scaffold were stained by fluoresceindiacetate (FDA) for morphology observation and the lengths and angles of the processes ineach group were also quantitatively analyzed. Scanning electron microcopy (SEM) wasemployed to observe the topography of scaffold and the ultrastructure of DRGs 3 d afterthe co-culture.Results HE staining indicated that the cellular components in the scaffoldwere removed completely.The length of processes elongation in CBD-NT3 treatment group wassignificantly longer than that in the controls 3 d after the co-culture (P＜0.05). The 95% confidenceinterval of the angle between the line which the process emerged from the cell soma to thegrowing tip of the process and the long axis of fiber was 18.8-20.7 degrees. The resultsof 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 adouble function for oriented guiding and inducing extension of cellular processeseffectively,which may provide a better therapeutic approach for spinal cord injury repair. Key words: Collagen;  Scaffold;  Neurotrophin-3;  Spinal cord injury