Introduction: Previously, we found that transplantation of Wnt3a-secreting fibroblasts and human mesenchymal stem cells (hMSCs) improves functional recovery after spinal cord injury (SCI) in rats and humans, respectively. Therefore, we predicted that Wnt3a-secreting hMSC transplantation in an SCI rat model would have greater effects than either of these transplantation methods alone.

Methods: hMSCs obtained from human umbilical cord blood were multiplied, cultivated, and transfected with pLenti-Wnt3a-GFP viral vector to produce Wnt3a-secreting hMSCs. A total of 50 female Sprague-Dawley rats were used and a moderate spinal cord injury was induced by applying a 250-kdyn force with an IH impactor. One week after injury, the injured site of the spinal cord was re-exposed. Cells were delivered using a 25-µL Hamilton syringe with a 33-gauge micro-needle inserted into the contusion site. Rats were divided into five groups: (1) Phosphate-buffered Saline injection group (sham group, n=10); (2) Wnt3a protein injection group (n=10); (3) hMSC transplantation group (n=10); (4) hMSCs transfected with pLenti vector transplantation group (n=10); and (5) hMSCs transfected with pLenti+Wnt3a vector transplantation group (n=10). Behavioral tests were performed for the first 3 days after injury and then weekly for 8 weeks. An examiner blinded to group-identifying information quantitatively assessed the locomotor performance of each rat according to the Basso-Beattie-Bresnahan (BBB) locomotor rating scale and ladder rung tests. Injured spinal cords were extracted, and axonal regeneration markers including ChAT, GAP43, and MAP2 were investigated by immunofluorescence, RT-PCR, and western blot.

Results: Seven weeks after transplantation (8 weeks after SCI), rats in the Wnt3a-MSC group achieved significantly higher average scores in motor behavior tests than the other groups did (p < 0.05). Immunofluorescent stains showed greater immunoreactivity of ChAT, GAP43, and MAP2 in the Wnt3a-MSC group than in other groups. RT-PCR and western blots revealed greater expression of these proteins in the Wnt3a-MSC group than in the other group (p < 0.05).

Conclusions: Wnt3a-secreting hMSC transplantation considerably improved neurological recovery and axonal regeneration in a rat SCI model.

Patient Care: The study showed that increased axonal regeneration and recovery of motor function in a rat SCI model by transplantation of Wnt3a-secreting human mesenchymal stem cells. Therefore, future clinical trials could be expected after ensuring the safety of the cells.

Learning Objectives: Describe the importance of transplantation of wnt3a secreting human mesenchymal stem cell in a spinal cord injury of animal model.

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