The Study Of Olfactory Ensheathing Cell Transplantation In Facial Nerve Defect Rat Model

Background:Facial nerve injury, and even the damage and fracture of facial nervecaused by related operations, can lead to facial paralysis. According to thedamage degree and time of facial nerve, there are conservative medicaltreatment and surgical treatment in clinical, both of which are oftendisappointing. Surgery such as nerve allograft or nerve autograft, isconstantly used to cure the facial nerve trunk fracture in a certaindistance,but the limited donor, nerve graft dysfunction, infection andrejection limit the application of the surgery, which also result in failureof surgery. Now with the development of tissue engineering, it is possibleto repair the injured facial nerve with the method of nerve regeneration.Using the appropriate seed cells, nerve conduits, and grafts fillingmaterial inside bridging fractured nerve are able to promote the facialnerve regenerate, so as to improve or restore facial nerve function. Atpresent the common seed cells include olfactory ensheathing cells, neuralstem cells, etc, materials of nerve conduit contain silicone tube, chitin,and the filler consists of sponge, collagen protein sponge and so on. Inrecent years, the studies about some materials above used in repairingperipheral nerve injury，such as peroneal nerve lesion，are much many,but the research on facial nerve injury is rarely reported. Objective：This experiment used that olfactory ensheathing cells can promote thenerve regeneration,combining with the form of nerve conduit, to explorethe possibility of repair of the injuried facial nerve.Methods:A total of32Sprague–Dawley male rats, each about250grams, wereused in present study. The rats were randomly divided into(1) Testgroup:To transplant0.1ml of OECs, whose concentration was adjusted inadvance, into nerve conduits;（2）Control group: To inject nerve conduitswith isodose stroke-physiological saline solution. Both of the groupsestablished the animal model with a total6mm defect in buccal branchesof facial nerve, and then bridged the facial defect with homemade nerveconduit. At12weeks the two groups rats were scarified for the study offacial nerve evoked potentials, nerve tracing and histology analysis.Tostatistical analysis with the evoked potential latency and amplitudevalue, facial nerve nuclear tracer fluorescence gold (FG) number, numberof regenerative nerve fibers under the electron microscope, the diameterof the fiber and the thickness of myelin sheath of the two groups, and tocompare the differences between the two groups.Results:1.There were significant differences in latency and amplitude of evokedpotentials between the two groups after treatment(P＜0.01).The latency is1.47±0.08ms in test group and2.76±0.12ms in control group. The amplitude in test group and control group is6.19±0.10ms and3.27±0.3ms,respectively.2. Significant differences in the number of FG could be found betweenthe two groups (P＜0.01).The number in test group is100.17±7.22ascompared to42.00±5.29in control group.3. The number of regenerative nerve fibers under electron microscope,the diameter of the fiber value, the thickness of myelin sheath in testgroup are superior to that of control group(P＜0.01). The values of thenumber of nerve fibers, fiber diameter and the thickness of myelin sheathin test group are2044.6±95.23，4.81±0.50μm，0.70±0.05μm,whilethat in control group are1113.1±88.58，3.45±0.36μm，0.47±0.07μm，respectively.Conclutions:OECs can promote the repair of the facial nerve. Collagen sponge, silicagel tube can be used as the materials of nerve conduit. It is effective forrepairing facial injury to make nerve conduit by the experimental method.Experimental results show that this method is feasible,and the results hasa significance to be promoted in clinical in the future.