Transplantation of Mesenchymal Stem Cells for Acute Spinal Cord Injury in Rats: Comparative Study between Intralesional Injection and Scaffold Based Transplantation

Experimental stem cell therapy for spinal cord injury (SCI) has been extensively investigated. The selection of effective cell transplantation route is also an important issue. Although various types of scaffold have been widely tried as a carrier of stem cells to the injured spinal cord, there was little comparative study to investigate the efficacy of transplantation comparing with conventional transplantation route. A total of 48 Sprague-Dawley rats were subjected to standardized SCI, followed by transplantation of allogeneic mesenchymal stem cells (MSCs), either via intralesional injection (IL group), or via the poly (lactic-co-glycolic acid) (PLGA) scaffold (IP group) or chitosan scaffold (IC group). Engraftment and differentiation of the transplanted cells, expression of neurotrophic factors in the injured spinal cord, and functional recovery were compared with those of the control group. The mean numbers of engrafted MSCs in the IL, IP, and IC groups were 20.6 +/- 0.7, 25.6 +/- 1.7, and 26.7 +/- 1.8, cells/high power filed (HPF) respectively. Results showed higher success rate of MSCs engraftment in the scaffold groups compared to the IL group. Expression of neuroprotective growth factors in the SCI lesions showed no significant differences between the IL, IP, and IC groups. The mean Basso, Beattie and Bresnahan locomotor scales at 6 weeks post-transplantation in the IL, IP, IC, and control groups were 7.9 +/- 1.1, 7.9 +/- 2.1, 8.7 +/- 2.1, and 2.9 +/- 1.0, respectively. The functional improvement was most excellent in the IC group. The scaffold based MSC transplantation for acute SCI presented the better cell engraftment and neuroprotective effect compared to the intralesional injection transplantation.