Differential degeneration patterns of the proximal and distal stumps in a sciatic gap-injury model in the rabbit highlight the role of gap-length in preventing regeneration

摘要

The study showed that in gaps longer that 20 mm, the distal stump is too far to provide a contingent of Schwann cells able to reach the axonal sprouting in the proximal stump. At the level of proximal stump, axons degenerate until newly re-growing freshly myelinated axons appear after 3 or 4 months. These new axons may progress aligned with the length of the guide for a limited distance. We then confirmed, in a larger animal model, that regeneration in longer gaps fails because the distance does not allow a timely match between proximal sprouts and distal Schwann cells. Our study, however, may suggest an un-expected advantage of longer conduits in being used to control or prevent regeneration from a proximal stump of an amputated nerve; sprouts are allowed to degenerate and new axons are not engulfed by fibroblast/myofibroblasts. This may be useful in control or prevention of amputation neuroma.