Maximum Number of Collaterals Developed by One Axon during Peripheral Nerve Regeneration and the Influence of That Number on Reinnervation Effects

Abstract

This study investigated the maximum number of collaterals that can be maintained by 1 axon during regeneration of rat peripheral nerve. The tibial nerve was transected, the proximal residual, with its variable number of axons, was fixed to the distal stump and served as the donor nerve. The number of myelinated axons was calculated after 12 weeks. An increasing ratio of distal stump axon numbers to proximal donor nerve axon numbers of 1.0, 1.83, 3.64 and 7.97 yielded ratios of regenerative myelinated axon numbers to proximal donor axon numbers of 0.98, 1.51, 2.39, 2.89, respectively, with an estimated maximum value of approximately 3.3 using the Hill function. The tibial function indexes and nerve conduction velocities of the regenerated tibial nerve were –44.1 ± 5.1 and 43.2 ± 5.3 m/s, –57.5 ± 4.7 and 18.6 ± 4.3 m/s, –80.2 ± 7.1 and 12.7 ± 3.7 m/s, and –85.4 ± 5.7 and 10.5 ± 3.9 m/s, respectively. It has been suggested that 1 axon can regenerate and maintain up to 3 or 4 collaterals in regenerated rat peripheral nerve.

Restoration of ulnar nerve motor function by pronator quadratus motor branch: an anatomical study

“…In our study, the ratio of the number of axons of the PQMB to the MBUN was about 1/3 to 1/4, which is close to the 1:3 ratio recommended for useful motor recovery after experiments with different donor-to-target axon ratios in rabbits [11]. Use of this ratio relies on the theory that axons in the proximal stump can undergo collateral sprouting and tend to increase the number of axons by 3-4 times [10]. Compared with the previous studies, our study involved the highest number of cadavers (Table 4).…”

Peripheral Nerve Regeneration Using a Keratin-Based Scaffold: Long-Term Functional and Histological Outcomes in a Mouse Model

“…[11][12][13] Some of the sprouting axons reach endoneurial tubes in the distal segment and regenerate to the target sensory receptor or neuromuscular junction. Other sprouts do not reach target organs and subsequently die back for lack of a trophic signal.…”

Controlling dispersion of axonal regeneration using a multichannel collagen nerve conduit

“…Though an autologous nerve graft is the gold standard of nerve graft repair, it has several disadvantages, including the need for an extra incision, loss of donor nerve function, mismatch in size between the donor nerve and the injured nerve, and a limited availability of donor nerve. A diverse array of synthetic and natural materials has been studied in peripheral nerve repair, but these studies have shown limited success [1][2][3][4][5][6][7][8][9][10][11][12].…”