[Comparison between effects of small intestinal submucosa graft and inside-out vein graft on repairing peripheral nerve defects]

Abstract

Objective: To make a comparison between the effects of the small intestinal submucosa (SIS) graft and the inside-out vein graft on repairing the peripheral nerve defects.

Methods: SIS was harvested from the fresh jejunum of the quarantined pig by curetting the musoca, the tunica serosa, and the myometrium; then, SIS was sterilized, dried and frozen before use. Thirty-six male SD rats were divided into 3 groups randomly, with 12 rats in each group. Firstly, the 10-mm defects in the right sciatic nerves were made in the rats and were respectively repaired with the SIS graft (Group A), the inside-out autologous vein graft (Group B), and the auto-nerve graft (Group C). At 6 weeks and 12 weeks after the operations, the right sciatic nerves were taken out, and the comparative evaluation was made on the repairing effects by the histological examination, the neural electrophysiological examination, the computerized imaging analysis, and the Trueblue retrograde fluorescence trace.

Results: The histological examination showed that the regenerated nerve fibers were seen across the defects in the three groups at 6 weeks after the operations. The nerve fibers were denser, the formed nerve myelin was more regular, and the fibrous tissue was less in Group A than in Group B; the nerve regeneration was more similar between Group A and Group C. At 12 weeks after the operations, the neural electrophysiological examination showed that the neural conductive rate was significantly lower in Group B than in Groups A and C (P<0.05), but no statistically significant difference was found between Group A and Group C (P > 0.05); the component potential wave amplitude was not statistically different between Group A and Group B; however, the amplitude was significantly lower in Groups A and B than in Group C (P < 0.05). At 6 weeks and 12 weeks after the operations, the computerized imaging analyses showed that the axis-cylinder quantity per area and the nerve-tissue percentage were significantly greater in Group A than in Group B (P < 0.05); the average diameter of the regenerated axis cylinder, the axis-cylinder quantity per area, and the nerve-tissue percentage were significantly lesser in Group B than in Group C (P < 0.05). At 12 weeks after the operations, the Trueblue retrograde fluorescence trace revealed that the positively-labeled neurons were found in the lumbar 3-6 dorsal root ganglion sections in the three groups.

Conclusion: The small intestinal submucosa graft is superior to the autologous inside-out vein graft in repairing the peripheral nerve defects and it is close to the auto-nerve graft in bridging the peripheral nerve defects. Therefore, the small intestinal submucosa is a promising biological material used to replace the auto-nerve graft.