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 and to investigate the feasibility of chitosan nerve conduit combined with autologous platelet-rich plasma(PRP)for repairing facial nerve defects.Methods:40 rabbits of 6 months old were divided into four groups.These experimental animals were used to make a 6mm defect model of bilateral facial nerve buccal branch on one side.The nerve conduit was used as a neural tube to bridge the facial nerve defect by creating a nerve regeneration room.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.The electrophysiological tests were performed at the 4th week and the 8th week after the operation.The degradation of chitosan nerve conduit was observed at the 4th week and the 8th week.HE staining and myelin staining were used to observe the neurological regeneration of the three groups at each time point.The number of medullated fibers and the thickness of myelin were measured using an image analysis system.The results were analyzed by SPSS22.0 statistical analysis software.Results: The chitosan nerve conduits were successfully prepared and used in the study of repairing rabbit facial nerve defects.After 4 weeks,the nerve ducts of group A and group B did not collapse,the tube wall of which become rough showing a dot-like absorption.The smaller regenerative nerves passed through the defect area in group A and group D.The fine cord-like tissue were connected to the distal side in group B and group C.After 8weeks,the chitosan nerve conduit was partially degraded in group A and group B.The regenerative nerve in the catheter bacome thick with rich blood vessels in group A and group D.The smaller regenerative nerves passed through the defect area in group B and group C.At the 4th week,the repaired nervers in group A and group D could generated action potential.At the 8th week,the regenerative nerve conduction velocity and amplitude of group A were better than those of group B and group C(P<0.05).The latency of muscle action potential in group A was lower than group B and group C(P<0.05).There was no significant difference in the latency of regenerative nerve conduction velocity,amplitude and muscle action potential between group A and group D(P>0.05).There was no significant difference in the latency of regenerative nerve conduction velocity,amplitude and muscle action potential between group B and group C(P>0.05).The regenerative nerve conduction velocity and amplitude of group D were better than those of group B and group C(P<0.05).The latency of muscle action potential in group D was lower than group B and group C(P<0.05).At the 4th week and 8th week,the number of myelinated fibers and the thickness of myelin in group A were proved better than group B and group C(P<0.05).There was no significant difference in the number of myelinated fibers and the thickness of myelin between group A and group D(P>0.05).There was no significant difference in the number of myelinated fibers and the thickness of myelin between group B and group C(P>0.05).The number of myelinated fibers and the thickness of myelin in group D were proved better than group B and group C(P<0.05).Conclusion: Chitosan nerve conduit can guide rabbits,facial nerve regeneration.It has better histocompatibility and can be degraded.Chitosan nerve conduit combined with PRP can further promote the repair of facial nerve defects and is expected to be used in clinical treatment of facial nerve defects to provide a new method.