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[An experimental study on effect of chitosan/polyvinyl alcohol nerve conduits on peripheral nerve regeneration in macaques].

OBJECTIVE
To investigate the effects of chitosan/polyvinyl alcohol (PVA) nerve conduits for repairing radial nerve defect in Macaques.


METHODS
Twelve adult Macaques weighing 3.26-5.35 kg were made the models of radial nerve defect (2 cm in length) and were randomly divided into 3 groups according to nerve grafting, with 4 Macaques in each group. Chitosan/PVA nerve conduit, non-graft, and autografts were implanted in the defects in groups A, B, and C, respectively. And the right radial nerves were used as normal control. At 8 months postoperatively, the general observation, electrophysiological methods, and histological examination were performed.


RESULTS
At 8 months postoperatively, the regenerated nerve bridged the radial nerve defect in group A, but no obvious adhesion was observed between the tube and the peripheral tissue. The regenerated nerve had not bridged the sciatic nerve defect in group B. The adhesions between the implanted nerve and the peripheral tissue were significant in group C. Compound muscle action potentials (CMAP) were detected in group A and group C, and no CMAP in group B. Peak amplitude showed a significantly higher value in normal control than in groups A and C (P < 0.05), but there was no significant difference between groups A and C (P > 0.05). Nerve conduction velocity and latency were better in normal control than in groups A and C, and in group C than in group A, all showing significant differences (P < 0.05). The density of myelinated fibers in groups A and C was significantly lower than that in normal control (P < 0.05), but there was no significant difference between groups A and C (P > 0.05). The diameter and the myelin sheath thickness of the myelinated fibers in normal control were significantly higher than those in groups A and C, and in group C than in group A, all showing significant differences (P < 0.05).


CONCLUSION
The chitosan/PVA nerve conduits can promote the peripheral nerve regeneration, and may promise alternative to nerve autograft for repairing peripheral nerve defects.