Axonal regeneration into Schwann cell‐seeded guidance channels grafted into transected adult rat spinal cord

Xiao Ming Xu, Véronique Guénard, Naomi Kleitman, Mary Bartlett Bunge

Research output: Contribution to journalArticlepeer-review

452 Scopus citations

Abstract

Schwann cells (SC) have been shown to promote regeneration in both the peripheral and central nervous systems. In this study we tested the ability of SC to enhance axonal regeneration in adult rat spinal cord by grafting SC- seeded guidance channels into transected cords. SC were purified in culture from adult inbred rat sciatic nerves, suspended in Matrigel, and seeded into semipermeable PAN/PVC channels (2.6 mm I.D. x 10 mm long) at a final density of 120 x 106 cells/ml. Channels filled with Matrigel alone served as controls. Adult isologous rat spinal cords were transected at the T8 level, and segments T9-T11 were removed. The rostral stump was inserted 1 mm into channels with capped distal ends. One month after grafting, a vascularized tissue cable was present within the channel in all animals. In SC-seeded channels (n = 14), a mean of 501 myelinated axons was found in the cable, and many axons extended 9-10 mm. Electron microscopy revealed typical SC ensheathment and myelination of axons with four times more unmyelinated than myelinated axons. Control channels (n = 8) contained fewer myelinated axons (mean = 71). When SC were prelabeled in culture with a nuclear dye, labeled nuclei were observed at 30 days, confirming SC survival. Astrocytes identified by glial fibrillary acidic protein staining did not migrate far into the cable, and prelabeled SC did not enter the cord. Lack of immunostaining for serotonin and dopamine β-hydroxylase indicated that supraspinal axons did not regenerate into the cable. Fast Blue injections into the middle of the cable (n = 3) marked spinal cord interneurons (mean = 306) as far as nine segments rostral (25 mm, C7) extending axons into the graft; fewer dorsal root ganglion neurons were retrogradely labeled. In conclusion, purified populations of SC transplanted within channels promote both propriospinal and sensory axonal regeneration in the adult rat thoracic spinal cord.

Original languageEnglish (US)
Pages (from-to)145-160
Number of pages16
JournalJournal of Comparative Neurology
Volume351
Issue number1
DOIs
StatePublished - Jan 2 1995

Keywords

  • cell culture
  • central nervous system regeneration
  • polymeric guidance channel
  • propriospinal neurons
  • spinal cord transplantation

ASJC Scopus subject areas

  • Neuroscience(all)

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