[An effect of the peripheral nerve allograft with subcutaneous preservation at different times on the nerve regeneration].

OBJECTIVE: To study an effect of the peripheral nerve allograft with subcutaneous preservation at different times on the sciatic nerve regeneration in rats. METHODS: Fifty-five Wistar rats were used in this experiment, which were randomly divided into the following 5 groups: the experimental groups (Groups A, B, C, 10 rats), the control group (Group D, 10 rats), and the donor group (Group E, 15 rats). In the experimental groups, a 15-mm segment of the sciatic nerve harvested from the donors was separately inserted into the subcutaneous compartment on the left thigh after the 1-week (Group A), 2-week (Group B), and 3-week (Group C) preservation; the segment of the sciatic nerve in the subcutaneous compartment was removed and transplanted into a 10-mm defect of the right sciatic nerve, which was made immediately. In Group D, a 10-mm sciatic nerve defect was made and immediately repaired in situ on the right thigh. The function of the sciatic nerve was evaluated by the sciatic functional index (SFI) at 2, 4, 6, 8, 10 and 12 weeks after operation. The histological and electrophysiological examinations were performed at 12 weeks after operation. RESULTS: After operation, SFI decreased gradually at 12 weeks after operation, SFI in Groups A and D was at the minimal level and had a significant difference compared with that in Groups B and C (P < 0.05). There was no significant difference between Group A and Group D. A large number of the myelinated nerve fibers and a small number of the unmyelinated nerve fibers were regenerated in Groups A and D. The number and the structure of the regenerated nerve were similar to the normal ones. The number and the size of the regenerated axon had a significant difference compared with those in Groups B and C (P < 0.05). There was no significant difference between Group A and Group D. The conduction velocity and the latent period of the motor nerve had significant differences between Groups A and D and Groups B and C (P < 0.05), and there was no significant difference between Group A and Group D. CONCLUSION: The nerve allograft with a 1-week subcutaneous preservation can promote nerve regeneration better.