Combination of an Electrospun Nanofiber Sheet Incorporating Methylcobalamin and a PGA-Collagen Tube Promotes Nerve Regeneration and Functional Recovery in a Rat Sciatic Nerve Defect Model

Abstract

Speaker's Bureau: Teijin Nakashima Co., Ltd. (Murase) We previously reported that a novel electrospun nanofiber sheet incorporating methylcobalamin (MeCbl sheet) to deliver it enough locally to the peripheral nerve injury site promotes peripheral nerve regeneration in a rat sciatic nerve crush injury model. The purpose of this study is to investigate the effect of combination of an MeCbl sheet and a PGA-collagen tube (Nerbridge) in a rat sciatic nerve defect model. We used a rat left sciatic nerve 10-mm defect models. Male Wistar rats weighing 180–220 g (n = 37) were used in this study. We divided them into 4 groups: (1) sham operation group (n = 10), (2) Nerbridge group, in which the gap was bridged with Nerbridge (n = 9), (3) Nerbridge + MeCbl sheet group, in which the gap was bridged with Nerbridge wrapped around in an MeCbl sheet (n = 8), and (4) autograft group, in which the sciatic nerve received a reversed autograft (n = 10). At 12 weeks after the operation, motor and sensory function were evaluated by the sciatic functional index, isometric tetanic force of the anterior tibial muscle, wet weight of the anterior tibial muscle, and the von Frey filament test. The electrophysiological analysis was performed by the compound muscle action potentials, the terminal latency, and nerve conduction velocity. We also demonstrated histological analysis by evaluating the number of total axons, the myelinated ratio, and the g-ratio. There was significant improvement in the Nerbridge + MeCbl sheet group for the von Frey filament test (Figure 48-1A), the terminal latency (Figure 48-1B), the ratio of myelinated axon (Figure 48-2A), and the g-ratio (Figure 48-2B) compared with Nerbridge group. The Nerbridge + MeCbl sheet group displayed the same recovery as the autograft group in the von Frey filament test (Figure 48-1A) and the ratio of myelinated axon (Figure 48-2A), although the recovery of the terminal latency (Figure 48-1B) and the g-ratio (Figure 48-2B) in the Nerbridge + MeCbl sheet group did not reach those in the autograft group. •An MeCbl sheet contributed to the recovery of sensory function and the promotion of myelinated ratio and the g-ratio after sciatic nerve injury.•An MeCbl sheet may be a new treatment option to promote nerve regeneration for an injured nerve bridged with an artificial nerve conduit.Figure 48-1BThe values of terminal latency in the Nerbridge + MeCbl sheet group was significantly shorter than that of the Nerbridge group. n = 8-10. *P < .05, **P < .01, ***P < .001; one-way analysis of variance followed by a post hoc, Tukey-Kramer HSD test.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 48-2AFluorescence micrographs showing cross-sectional slices of sciatic nerves labeled for MBP (red) and NF200 (green). The Nerbridge + MeCbl sheet group displayed a higher ratio of myelinated axon than that in the Nerbridge group and the same as that in the autograft group. Scale bar, 20 μm. n = 5 per group.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 48-2BPhotomicrographs of cross-sectional slices of sciatic nerves under a transmission electron microscope. The Nerbridge + MeCbl sheet group displayed a lower g-ratio than that in the Nerbridge group. Scale bar, 2 μm. n = 3–5. *P < .05, **P < .01, ***P < .001; one-way analysis of variance followed by a post hoc, Tukey-Kramer HSD test.View Large Image Figure ViewerDownload Hi-res image Download (PPT)