Olfactory ensheathing cells promote nerve regeneration and functional recovery after facial nerve defects

Olfactory ensheathing cells from the olfactory bulb and olfactory mucosa have been found to increase axonal sprouting and pathfinding and promote the recovery of vibrissae motor performance in facial nerve transection injured rats. However, it is not yet clear whether olfactory ensheathing cells promote the reparation of facial nerve defects in rats. In this study, a collagen sponge and silicone tube neural conduit was implanted into the 6-mm defect of the buccal branch of the facial nerve in adult rats. Olfactory ensheathing cells isolated from the olfactory bulb of newborn Sprague-Dawley rats were injected into the neural conduits connecting the ends of the broken nerves, the morphology and function of the regenerated nerves were compared between the rats implanted with olfactory ensheathing cells with the rats injected with saline. Facial paralysis was assessed. Nerve electrography was used to measure facial nerve-induced action potentials. Visual inspection, anatomical microscopy and hematoxylin-eosin staining were used to assess the histomorphology around the transplanted neural conduit and the morphology of the regenerated nerve. Using fluorogold retrograde tracing, toluidine blue staining and lead uranyl acetate staining, we also measured the number of neurons in the anterior exterior lateral facial nerve motor nucleus, the number of myelinated nerve fibers, and nerve fiber diameter and myelin sheath thickness, respectively. After surgery, olfactory ensheathing cells decreased facial paralysis and the latency of the facial nerve-induced action potentials. There were no differences in the general morphology of the regenerating nerves between the rats implanted with olfactory ensheathing cells and the rats injected with saline. Between-group results showed that olfactory ensheathing cell treatment increased the number of regenerated neurons, improved nerve fiber morphology, and increased the number of myelinated nerve fibers, nerve fiber diameter, and myelin sheath thickness. In conclusion, implantation of olfactory ensheathing cells can promote regeneration and functional recovery after facial nerve damage in rats.

[Experimental study of using chitosan nerve conduit combined with PRP to repair facial nerve defect]

Objective:The purpose of this study was to produce chitosan nerve conduit in order to investigate the feasibility of chitosan nerve conduit combined with autologous platelet-rich plasma (PRP) for repairing facial nerve defects.Method:Forty New Zealand white rabbits were randomly divided into four groups (n=10 in each group).Establishment of the facial nerve defect model of the upper buccal branches was placed in the nerve regeneration catheter and injected with the same amount of PRP and saline. The PRP was injected into the chitosan nerve conduit as group A. The physiological saline was injected into the chitosan nerve conduit as group B. The physiological saline was injected into the silicone tube as group C. The PRP was injected into the silicone tube as group D. Eight weeks later,facial nerve gross observation,facial nerve electrophysiological tests,histological observation,image analysis,valuation of nerve regeneration recovery were detected.Result:Five patients were lost to follow up (all five in the modified Semont group),and three patients failed to complete treatment (all three in the Epley group). The sequelae at the 3rd day and one week after modified Semont maneuver were 27 and 9,while 41 and 15 in Epley group. The efficacy rates at the 3rd day and one week after modified Semont maneuver were 91.7% and 98.3%,and 91.9% and 96.8% in Epley group retrospectively. The sequelae and short-term effective rate of patients in modified Semont group was no difference when compared with that in Epley group (P>0.05).Conclusion:The chitosan nerve conduit combined with PRP has a certain effect on the repair of facial nerve defects and is expected to be applied to the repair of clinical facial nerve defects.