Collagen/β-TCP nerve guidance conduits promote facial nerve regeneration in mini-swine and the underlying biological mechanism: A pilot in vivo study.

This study aimed to evaluate the efficiency of new nerve guidance conduits (NGCs) in bridging facial nerve gaps, and investigate the underlying biological mechanisms implicated in the regeneration process. A collagen/β-TCP conduit was prepared and applied to a facial nerve gap in a mini-swine model. Functional recovery and axonal regeneration were further evaluated by electrophysiological and histological examinations at 3 months after surgery. Furthermore, the global transcriptomic profiles of regenerated and normal tissues were analyzed by gene microarray to identify the differentially expressed genes at day three and seven, postoperatively. Subsequently, associated biological processes were analyzed by gene ontology (GO) enrichment analysis. The electrophysiological examination and morphological analysis revealed that significant nerve regeneration effects were achieved in the Col/β-TCP group (p < 0.05). Transcriptional analysis revealed that at day three post-surgery, the majority of overexpressed genes were associated with inflammatory, immune and stimuli response, accompanied by angiogenesis, while at day seven, the majority of overexpressed genes were associated with cell, tissue and organ regeneration and development, synaptic transmission, neurogenesis, and neuronal differentiation, as well as the WNT, MAPK/ERK, and JAK/STAT signaling pathways. In conclusion, the present results suggest that collagen/β-TCP NGCs provide a promising tubular micro-environment for nerve regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1122-1131, 2019.