Transplantation of Olfactory Mucosa as a Scaffold for Axonal Regeneration Following Spinal Cord Contusion in Rats

Object: The inability of the spinal cord to regenerate after SCI is due to the extremely limited regenerative capacity of most central nervous system (CNS) axons, along with the hostile environment of the adult CNS, which does not support axonal growth. It seems that for successful axonal regeneration to take place, a supportive local environment is required after the injury. We have previously reported that transplantation of the olfactory mucosa is effective in restoring functional recovery in rats following spinal cord transaction. In this study, we examined histological features of olfactory mucosa grafts in rats subjected to a spinal cord contusion protocol. Respiratory mucosa was utilized as a control, as we have previously found that respiratory mucosa does not support neuronal generation. Methods: The rats spinal cords were crash-injured by dropping a 10-g metal rod from a height of 7.5 cm, and a couple of weeks later, the injury sites were exposed, and both olfactory and respiratory mucosae were inserted into the posterior sulcuses of the spinal cord. The each number of olfactory and mucosa transplanted rats were five. The Basso, Beattie, and Bresnahan (BBB) score was observed. Immunohistochemical study for neurofilament was performed. Results: Olfactory mucosa transplanted rats following spinal cord injury can support at least partial hind limb motor recovery compared with respiratory mucosa transplanted rats and we identified numerous axons surrounding the transplanted olfactory mucosa cells, and penetrating the olfactory mucosa at the transplant site. Conclusion: Olfactory mucosa might be a suitable scaffold for axonal regeneration.