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.