Repair of rat facial nerve defects with rabbit acellular nerve by chemical extraction

OBJECTIVE To explore the possibility to bridge the facial nerve defects by xenogeneic acellular nerve. METHODS Sixty Wistar rats were randomly and equally divided into three groups: xenogeneic acellular nerve graft, nerve autograft and xenogeneic fresh nerve graft. The inferior buccal branch of the left facial nerve of ratswere exposed and 6 mm long segment of the nerve was removed, and replaced by above-mentioned three kinds of nerve grafts respectively. The acellular nerve was chemically extracted by the detergents of 30 ml/L TritonX-100 and 40 g/L deoxycholate sodium. The recovery of function and morphology of nerve regeneration was observed by using electromyography, horseradish peroxidase retrograde trace, methylene blue staining, transmission electron microscope respectively at the 5th month after operation. RESULTS In the xenogeneic acellular nerve graft group, no excessive signs of rejected and absorbed reaction could be observed in the acellular segments. The latency ratio of nerve-muscle action potential on normal side / experimental side was 0.663±0.142; The amplitude ratio of nerve-muscle action potential on experimental side / normal side was 0.334± 0.032; The ratio of the labeled facial motor neurons on experimental side / normal side was 0.293±0.023. The regenerated nerve fibers had normal morphological and structural characters under transmission electron microscope. The results in the xenogeneic acellular nerve graft group were similar to those of the nerve autograft group(P0.05). In the xenogeneic fresh nerve graft group, the xenogeneic nerve segment was rejected and absorbed by the recipient. CONCLUSION Xenogeneic acellular nerve could sustain facial nerve regeneration, and may be a substitute to autograft for repairing facial nerve defects.