Improving nerve regeneration of acellular nerve allografts seeded with SCs bridging the sciatic nerve defects of rat

Abstract

The objective of the paper is to evaluate the effect of acellular nerve allografts (ANA) seeded with Schwann cells to promote nerve regeneration after bridging the sciatic nerve defects of rats and to discuss its acting mechanisms. Schwann cells were isolated from neonatal Wistar rats. In vitro Schwann cells were microinjected into acellular nerve allografts and co-cultured. Twenty-four Wistar rats weighing 180-220 g were randomly divided into three groups with eight rats in each group: ANA seeded with Schwann cells (ANA + SCs), ANA group and autografts group. All the grafts were, respectively, served for bridging a 10-mm long surgically created sciatic nerve gap. Examinations of regeneration nerve were performed after 12 weeks by transmission electron microscope (TEM), scanning electron microscope (SEM), and electrophysiological methods, and then analyzed statistically. The results obtained indicated that in vitro Schwann cells displayed the feature of bipolar morphology with oval nuclei. Compared with ANA group, the conduction velocity of ANA + SCs group and autograft group was faster after 12 weeks, latent period was shorter, and wave amplitude was higher (P < 0.05). The difference between ANA + SCs group and autograft group is not significant (P > 0.05). Regeneration nerve myelinated fiber number, myelin sheath thickness, and myelinated fibers/total nerves (%) in both ANA + SCs group and autograft group are higher than that in ANA group; the difference is significant (P < 0.05). The difference between the former two is not significant (P > 0.05). In conclusion, ANA seeded with SCs could improve nerve regeneration and functional recovery after bridging the sciatic nerve gap of rats, which offers a novel approach for the repair peripheral nerve defect.

Fig. 1

a SCs were positive cells for S-100 using the immunohistochemistry staining (light microscope, ×200). b Regeneration myelinated fiber in ANA + SCs group using the toluidine blue staining, scale bar = 50 μm. c Regeneration myelinated fiber in ANA group using the toluidine blue staining, scale bar = 50 μm. d Regeneration myelinated fiber in autograft group using the toluidine blue staining, scale bar = 50 μm

Fig. 2

a Myelin sheath of regeneration nerve in ANA + SCs group (TEM, ×8,000). b Myelin sheath of regeneration nerve in ANA group (TEM, ×8,000). c ANA maintain hollow conduit construction after hypotonic-chemical detergent method (SEM, ×5,000). d SCs displayed the feature of bipolar morphology with oval nuclei and end to end arrangement in ANA(SEM, ×10,000)