Motor Recovery after Chronic Spinal Cord Transection in Rats: A Proof-of-Concept Study Evaluating a Combined Strategy

CNS Neurol Disord Drug Targets. 2019;18(1):52-62. doi: 10.2174/1871527317666181105101756.

Abstract

Background: The chronic phase of Spinal Cord (SC) injury is characterized by the presence of a hostile microenvironment that causes low activity and a progressive decline in neurological function; this phase is non-compatible with regeneration. Several treatment strategies have been investigated in chronic SC injury with no satisfactory results. OBJECTIVE- In this proof-of-concept study, we designed a combination therapy (Comb Tx) consisting of surgical glial scar removal plus scar inhibition, accompanied with implantation of mesenchymal stem cells (MSC), and immunization with neural-derived peptides (INDP).

Methods: This study was divided into three subsets, all in which Sprague Dawley rats were subjected to a complete SC transection. Sixty days after injury, animals were randomly allocated into two groups for therapeutic intervention: control group and animals receiving the Comb-Tx. Sixty-three days after treatment we carried out experiments analyzing motor recovery, presence of somatosensory evoked potentials, neural regeneration-related genes, and histological evaluation of serotoninergic fibers.

Results: Comb-Tx induced a significant locomotor and electrophysiological recovery. An increase in the expression of regeneration-associated genes and the percentage of 5-HT+ fibers was noted at the caudal stump of the SC of animals receiving the Comb-Tx. There was a significant correlation of locomotor recovery with positive electrophysiological activity, expression of GAP43, and percentage of 5-HT+ fibers.

Conclusion: Comb-Tx promotes motor and electrophysiological recovery in the chronic phase of SC injury subsequent to a complete transection. Likewise, it is capable of inducing the permissive microenvironment to promote axonal regeneration.

Keywords: Evoked potentials; Fibrin glue; GAP43; mesenchymal stem cells; neural regeneration; neural-derived peptides; protective autoimmunity; scar removal; serotonin..

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2,2'-Dipyridyl / therapeutic use
  • Animals
  • Cicatrix / surgery*
  • Combined Modality Therapy / methods*
  • Evoked Potentials / physiology
  • Female
  • Freund's Adjuvant / therapeutic use
  • Gene Expression / drug effects
  • Mesenchymal Stem Cell Transplantation*
  • Motor Activity / drug effects
  • Nerve Regeneration / drug effects
  • Rats
  • Recovery of Function / drug effects*
  • Recovery of Function / immunology*
  • Spinal Cord Injuries* / drug therapy
  • Spinal Cord Injuries* / physiopathology
  • Spinal Cord Injuries* / surgery
  • Spinal Cord Injuries* / therapy
  • Tryptophan / analogs & derivatives
  • Tryptophan / therapeutic use

Substances

  • N-(2-naphthalene)sulfonyl-DL-tryptophan
  • 2,2'-Dipyridyl
  • Tryptophan
  • Freund's Adjuvant