The effect of cell-mediated delivery of combination VEGF165, GDNF, and NCAM1 genes on molecular and cellular reactions in the spinal cord of pigs with contusion trauma

Abstract

Currently, the treatments for spinal cord injury are limited. Gene therapy is one of the most promising approaches aimed at overcoming negative post-traumatic consequences in the spinal cord. Numerous studies performed in rodents indicate a positive effect of the delivery of therapeutic genes to the spinal cord to stimulate neuroregeneration. However, to bring the developed protocols of gene therapy to the stage of clinical trials, it is necessary to verify the results obtained in experiments on large laboratory animals. Objective: Immunofluorescence analysis of the response of markers of cell stress and apoptosis, synaptic proteins and neuroglia in the spinal cord of female vietnamese pot-bellied pigs after intrathecal delivery of genes encoding vascular endothelial growth factor (VEGF165), glial-derived neurotrophic factor and neuronal cell adhesion molecule (NCAM1), using human umbilical cord blood mononuclear cells (UCBMC). In experimental pigs (n = 2), 4 hours after modeling a dosed contusion injury of the spinal cord at the Th8-Th9 level, 2х106 genetically modified UCBMCs overexpressing recombinant VEGF, GDNF, and NCAM molecules in 200 |jl of saline were intrathecally injected. Control animals (n = 2) were injected with 200 jl of saline into the cerebrospinal fluid. Intact pigs (n = 2) were used to obtain baseline values for immunofluorescence analysis of post-traumatic molecular and cellular responses. After 60 days, immunofluorescence analysis in the rostral and caudal parts of the spinal cord relative to the epicenter of injury revealed positive changes in experimental pigs against the background of cell-mediated delivery of the VeGf165, GDNF, and NCAM1 genes. In the anterior horns of the rostral and caudal spinal cord of animals from the therapeutic group, a higher level of fluorescence of the synaptic protein synaptophysin, a lower number of astrocytes and microglial cells were found, which may indicate functional recovery of neurons and suppression of the development of astrogliosis. In the rostral section, in the area of the corticospinal tract, gene therapy maintained the number of oligodendrocytes, which ensure myelination of regenerating axons. The results obtained suggest that genetically modified UCBMCs, overexpressing recombinant molecules VEGF and GDNF (as therapeutic molecules) and NCAM (as a molecule providing survival and targeted targeting of cell carriers), contribute to post-traumatic regeneration of the spinal cord.