Reknitting the spinal cord using a self-assembling peptide nanofiber scaffold to promote functional recovery

Abstract

Objective: The present study tests whether self-assembling peptide nanofiber scaffold (SAPNS) with seeded stem or Schwann cells could reknit the cystic cavities due to spinal cord injury. Methodology: neural stem cells (NSCs) or Schwann cells (SCs) isolated from GFP transgenic Sprague-Dawley rats were cultured within SAPNS respectively. Some of them were fixed after 4 weeks cultured in vitro to assess the states of the cells within the SAPNS. The others cultured for 6 days were transplanted into the dorsal column transected spinal cord of Sprague-Dawley rats. Result: SCs and NSCs could survive and migrate 3-dimensionally (3-D) within SAPNS in vitro, almost no apoptosis nucleus bodies could be found. SCs within SAPNS were P75 positive exclusively whether cultured in vitro or 6 weeks after been transplanted. Moreover, some of SCs showed tube-like processes and MBP positive within the spinal cord injured site. Part of NSCs differentiated into neurons (βIII-tubulin-positive), astrocytes (GFAP-positive) and oligodendrocytes (Rip-positive) both in vitro and in vivo. Robust migration of host cells, growth of blood vessels and axons were found to grow into the transplanted SAPNS scaffolds and evidence of improved locomotor activity in the hindlegs were observed. There was no obvious cavity or gap between the scaffold and the host. Conclusion: SAPNS could provide a friendly 3-D environment for the survival, migration and differentiation of NSCs and SCs both in vitro and in vivo; SAPNS could integrate very well with and bridge the injured spinal cord. SAPNS with SCs or NSCs, or SAPNS alone will elicit axon regeneration and locomotor function recovery of the spinal cord injured. corresponding author: Wutian Wu: wtwu@hkucc.hku.hk