Spinal cord is the main pathway of communication between brain and peripheral nervous system. Spinal cord injury (SCI) often leads to sensory and motor functional deficits below the injury level, causing severe disability and bringing heavy burden to family and society. Spinal cord injury repair is one of the most challenging medical problems, and no effective therapeutic methods has been developed. The spinal cord is a complex tissue composed of various types of nerve cells, nerve fibers, and blood vessels. After SCI, the injury distance usually reaches several centimeters, resulting in the loss of multiple cells and the interruption of neural connections. Hence, it is difficult to achieve a satisfactory effect by transplanting a single type cell to repair severe SCI. A few studies have reported that transplantation of rat embryonic central neural tissue pieces into the injury area of newborn or adult rats for SCI treatment. The embryonic central neural tissue pieces partially replaced the lost spinal cord tissue, survived in the lesion area of the newborn or adult host, newly-formed neural connections, and thus showed positive effect on motor function recovery after surgery. However, studies of the therapeutic effect of adult spinal cord tissue pieces on SCI repair have not been reported. Therefore, it is necessary to investigate utilization of adult spinal cord tissue pieces to reconstruct neural function and restore motor function.
Biologists from the Institute of Genetics and Developmental Biology, Chinese Academy of Science, transplanted adult spinal cord grafts (aSCGs) into the lesion sites of the adult host with spinal cord transection to improve the locomotor function.
"We first reported the use of aSCGs derived from adult rat spinal cord tissue as an allograft for the treatment of complete SCI in adult rats." said Dr. He Shen, the first author for this work. The results of this research showed that the transplantation of aSCGs promoted the recovery of motor function. The transplanted allogeneic aSCGs tissues as well as neurons and oligodendrocytes in the donor segments survived. "In addition, to provide a favorable microenvironment for SCI treatment, we further applied a growth factor cocktail containing three growth factors (brain-derived neurotrophic factor, neurotrophin-3 and vascular endothelial growth factor) to the aSCG transplants", said He. With the presence of the growth factors, the survival levels of donor segments and cells were boosted. And therefore, the locomotor function was significantly improved 12 weeks after transplantation of aSCGs into the spinal cord lesion site in adult rats. "To enhance functional recovery after transplanting aSCGs in lesion sites, efficient rebuilding of neuronal connections by both the donor and host s neural cells is required. Thus, in future we may incorporate aSCGs with modified biomaterials for SCI treatment to improve the survival of the grafts, accelerate neovascularization, and promote formation of neural connections between the donor tissues and recipients", said Professor Jianwu Dai, the co-corresponding author.
These encouraging results indicated that treatment of complete SCI by transplanting aSCGs, especially in the presence of growth factors, has a positive effect on motor functional recovery. All the authors hope that this new strategy will be considered as a possible therapeutic method for SCI in the future.
This work was supported by grants from the National Natural Science Foundation of China (81891002) and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16020100).
See the article: Shen, H., Chen, X., Li, X., Zhang, J., Jia, K., Xiao, ZF., Dai, JW. (2019). Transplantation of adult spinal cord grafts into spinal cord transected rats improves their locomotor function. Sci China Life Sci, in press, https:/