Rewiring of regenerated axons by combining treadmill training with semaphorin3A inhibition

Liang Zhang, Shinjiro Kaneko, Kaoru Kikuchi, Akihiko Sano, Miho Maeda, Akiyoshi Kishino, Shinsuke Shibata, Masahiko Mukaino, Yoshiaki Toyama, Meigen Liu, Toru Kimura, Hideyuki Okano, Masaya Nakamura

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Background: Rats exhibit extremely limited motor function recovery after total transection of the spinal cord (SCT). We previously reported that SM-216289, a semaphorin3A inhibitor, enhanced axon regeneration and motor function recovery in SCT adult rats. However, these effects were limited because most regenerated axons likely do not connect to the right targets. Thus, rebuilding the appropriate connections for regenerated axons may enhance recovery. In this study, we combined semaphorin3A inhibitor treatment with extensive treadmill training to determine whether combined treatment would further enhance the "rewiring" of regenerated axons. In this study, which aimed for clinical applicability, we administered a newly developed, potent semaphorin3A inhibitor, SM-345431 (Vinaxanthone), using a novel drug delivery system that enables continuous drug delivery over the period of the experiment. Results: Treatment with SM-345431 using this delivery system enhanced axon regeneration and produced significant, but limited, hindlimb motor function recovery. Although extensive treadmill training combined with SM-345431 administration did not further improve axon regeneration, hindlimb motor performance was restored, as evidenced by the significant improvement in the execution of plantar steps on a treadmill. In contrast, control SCT rats could not execute plantar steps at any point during the experimental period. Further analyses suggested that this strategy reinforced the wiring of central pattern generators in lumbar spinal circuits, which, in turn, led to enhanced motor function recovery (especially in extensor muscles). Conclusions: This study highlights the importance of combining treatments that promote axon regeneration with specific and appropriate rehabilitations that promote rewiring for the treatment of spinal cord injury.

Original languageEnglish
Article number14
JournalMolecular brain
Volume7
Issue number1
DOIs
Publication statusPublished - 2014 Mar 10

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Keywords

  • Axonal regeneration
  • Drug delivery system
  • Inhibitor
  • Rehabilitation
  • Rewiring
  • Semaphorin3A

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience

Cite this

Zhang, L., Kaneko, S., Kikuchi, K., Sano, A., Maeda, M., Kishino, A., Shibata, S., Mukaino, M., Toyama, Y., Liu, M., Kimura, T., Okano, H., & Nakamura, M. (2014). Rewiring of regenerated axons by combining treadmill training with semaphorin3A inhibition. Molecular brain, 7(1), [14]. https://doi.org/10.1186/1756-6606-7-14