Activated Schwann cells combined with umbilical cord blood mesenchymal stem cell transplantation for repair of spinal cord injury

Objective To observe the variation of neuronal markers after co-transplantation of activated Schwann cells (ASCs) and human umbilical cord blood mesenchymal stem cells (HUCBMSCs)into rat spinal cord injury (SCI). Also, we discuss whether these two types of cells grafted into the injured site of spinal cord have the ability of promoting axonal regeneration and functional recovery after SCI. Methods SCI model in Wistar rat (Female, 8 weeks’ old) was created at T10 segment with NYU Impactor-Ⅱmachine of 10 g×50 mm weight drop.80 SCI rats were classified into 4 groups randomly: blank control group, ASCs transplantation group, HUCBMSCs transplantation group and co-transplantation group of ASCs and HUCBMSCs. 1, 2, 3, 4 weeks after operation, 3 animals of each group were sacrificed, and injured spinal cord tissue were used for Western blotting and Real-time polymerase chain reaction analysis [nuclear factor (NF)-200, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP)]. Basso, Beattie, and Bresnahan (BBB) score was carried out at the 3rd day and at weekly after intervals injury.12 weeks later, 8 rats in each group were selected to carry out 10% BDA anterograde tracing mark.2 weeks later, the animals were sacrificed, the spinal cord tissue with injured lesion was taken out and fast cryostat sections (5 μm) was made followed by BDA developing, hematoxylin and eosin (HE) and immunochemistry (NF-200, MBP, GFAP) staining. Results Western blotting and Real-time PCR analysis revealed that NF-200 and MBP expressed higher with time while the co-graft group is the highest (4 weeks after injury, NF-200: 4.581±0.588, MBP: 3.922±0.259). From the 4th week after cell-transplantation, BBB score in co-graft group was significantly higher than that in other 3 groups (P=0.000). The rats of co-graft group recoverd to the largest extent. BDA anterograde injured site in co-graft group than that in other 3 groups, while little in control group (P=0.000). HE staining showed that the injured cavity was the smallest one in cell co-graft group when compared with other 3 groups. Conclusion The results indicate that the co-transplantation fully takes advantage of ASCs to promote HUCBMSCs differentiate into neurons. This is more effective than single cell transplantation in promoting axonal regeneration and functional recovery after rat’s spinal cord injury. Key words: Umbilical cord blood mesenchymal stem cells; Activated Schwann cells; Spinal cord injury; Neural repair; Differentiation; Co-transplantation