Department of Orthopedics, Traumatic Orthopedic Institute of PLA, Beijing Army General Hospital, Beijing 100700, China

Abstract 

Objective 
Combine olfactory ensheathing glia (OEG) implantation with ex vivo non-viral vector-based neurotrophin-3 (NT-3) gene therapy in attempting to enhance regeneration after thoracic spinal cord injury (SCI). 
Methods 
Primary OEG were transfected with cationic liposome-mediated recombinant plasmid pcDNA3.1(+)-NT3 and subsequently implanted into adult Wistar rats directly after the thoracic spinal cord (T9) contusion by the New York University impactor. The animals in 3 different groups received 4×105 OEG transfected with pcDNA3.1(+)-NT3 or pcDNA3.1(+) plasmids, or the OEGs without any plasmid transfection, respectively; the fourth group was untreated group, in which no OEG was implanted. 
Results 
NT-3 production was seen increased both ex vivo and in vivo in pcDNA3.1(+)-NT3 transfected OEGs. Three months after implantation of NT-3-transfected OEGs, behavioral analysis revealed that the hindlimb function of SCI rats was improved. All spinal cords were filled with regenerated neurofilament-positive axons. Retrograde tracing revealed enhanced regenerative axonal sprouting. 
Conclusion 
Non-viral vector-mediated genetic engineering of OEG was safe and more effective in producing NT-3 and promoting axonal outgrowth followed by enhancing SCI recovery in rats.

Keywords

functional recovery; gene therapy; neurotrophin-3; olfactory ensheathing glia; regeneration; spinal cord injury; non-viral vectors

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