Cell activity during peripheral nerve defect repair process using a nerve scaffold

// Chan Zhou 1, * , Jin Li 1, 2, * , Huajian You 3 , Jinfeng Lv 1 , Jinlong Yang 1 and Bin Liu 2 1 Chongqing Academy of Animal Science, Chongqing 400015, China 2 Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China 3 Chongqing Academy of Chinese Materia Medica, Chongqing 400065, China * These authors contributed equally to this work Correspondence to: Jinlong Yang, email: yjlfirst@163.com Bin Liu, email: xytom@swu.edu.cn Keywords: fibroin fibre; inflammatory cell; Schwann cell; fibroblast; peripheral nerve defect Received: August 24, 2017      Accepted: November 17, 2017      Published: December 05, 2017 ABSTRACT Peripheral nerve defects, but not artificial nerves, are repaired by endogenous cells. We examined cell activity during the repair process in the presence of autologous nerves and artificial preparations in order to guide future artificial nerve fabrication. PLGA tubes, nerve scaffolds comprising a PLGA tube plus 6,000 fibroin fibers, or autologous nerves were implanted into 10 mm rat sciatic nerve defects ( n = 60 per group). Over a period of 1-20 weeks after nerve grafting, sections were stained and imaged to distinguish the cell types present and we quantified the recovery of motor and sensory function in the surgically implanted limb. We observed a decreasing trend in inflammatory cell and fibroblast counts over time which ranked in magnitude as: (PLGA group > nerve scaffold > autologous nerve> sham) and an opposite trend in Schwann cell counts. Differences in withdrawal time from hot water and static sciatic index (SSI) indicated that, after repair, sensory and motor function were best in the sham group, followed by the autologous group, the nerve scaffold group, and the PLGA group. These findings indicate that the inflammatory reaction is significant in the first two weeks after nerve grafting, followed by the rebirth of fibroblasts and Schwann cells, which guide axon regeneration. This inflammatory response was a fundamental stage of peripheral defect repair, but a weaker inflammatory response corresponded to better recovery of sensorimotor functional.