Transplantation of Olfactory Mucosa Improve Functional Recovery and Axonal Regeneration Following Sciatic Nerve Repair in Rats

Background: Olfactory ensheathing glia (OEG) has been shown to have a neuroprotective effect after being transplanted in rats with spinal cord injury. This study was conducted to determine the possible beneficial results of olfactory mucosa transplantation (OMT) which is a source of OEG on functional recovery and axonal regeneration after transection of the sciatic nerve. Methods: In this study, 36 adult female Sprague-Dawley rats were used. The sciatic nerve was transected in 24 rats and immediately repaired by sciatic-sciatic anastomosis, and randomly divided equally into two groups. The experimental group received the OMT at the transected site and the control group received the respiratory mucosa transplant. In another twelve rats as sham-operated animals, the sciatic nerve was exposed but no transection was made. DiI retrograde tracing was injected in the gastrocnemius muscle two months after surgery to allow visualization of the extent of axonal regeneration. Functional recovery was also assessed at 15, 30, 45 and 60 days after surgery using walking track analysis and sciatic function index (SFI) calculations. Results: The total number of DiI labeled motorneurones in the ventral horn (L4-L6) and the SFI scores were significantly higher in the group of rats that received olfactory mucosa rather than respiratory mucosa. Conclusions: The outcome indicates that olfactory mucosa is a useful treatment to improve nerve regeneration in mammals with peripheral nerve injury.