The chitosan molecule can promote nerve cell adherence and growth along the surface of the material. It can enhance the adherence and influx of Schwann cells, thus encouraging the growth of axons. However, physical nerve guidance by a nerve conduit may not be sufficient to foster optimal recovery. Dr. Huawei Liu and colleagues from Institute of Stomatology, Chinese PLA General Hospital in China prepared microspheres containing nerve growth factor for sustained release by a compound method, and implanted them into chitosan conduits to repair 10-mm defects on the right buccal branches of the facial nerve in rabbits. Researchers found that the sustained in vitro release of active nerve growth factor lasted for at least 90 days.
The muscular atrophy induced by facial nerve defects was attenuated, and the nerve conduction velocity and amplitude were significantly increased. Moreover, microspheres for sustained release of nerve growth factor in combination with chitosan conduits improved axon and myelin sheath regeneration of injured facial nerve. These findings, published in the Neural Regeneration Research (Vol. 8, No. 33, 2013), indicate that the combination of nerve growth factor-releasing microspheres and chitosan conduits exhibits superior effects in repairing facial nerve injury compared with nerve growth factor alone.