Nerve regeneration through allogenic nerve grafts in mice.

Nerve regeneration through cryo-treated xenogeneic nerve grafts.

“…The evidence in the present study indicates that an almost identical process of nerve regeneration occurs in the cryo-treared xenogeneic graft as in similarly treated autografts (IDE, 1983 ;ICE et al, 1983) and allografts (OSAWA et al, 1986). In short, Schwann cells in the graft are degraded, whereas their basal laminae remain in the form of tubes without being phagocytized by macrophages, and regenerating axons grow out through such basal lamina tubes.…”

“…It has been recognized that these treatments improve to some extent the nerve regeneration in allogeneic grafts. In a previous study using sciatic nerve grafts between two different strains of mice, C57BL/6N and C3H/HeN, we demonstrated that Schwann cell basal lamina tubes serve as effective conduits for regenerating nerves even in the allograft (OSAWA et al, 1986). Judging from the fact that basal laminae and collagen fibrils were not phagocytized by macrophages, but left apparently intact in the allogeneic grafts, it can be assumed that there were no significant differences in the components of these extracellular substances in the above two strains of mice, and that little or no immunological reaction to those substances occurred between these strains.…”

“…In short, Schwann cells in the graft are degraded, whereas their basal laminae remain in the form of tubes without being phagocytized by macrophages, and regenerating axons grow out through such basal lamina tubes. Such regenerating axons can extend far enough to reach their targets of the skin and muscles, as in the case of allogeneic grafts (OsAwA et al, 1986). The process of nerve regeneration through xenogeneic grafts appears slightly delayed in the early period of regeneration (4 and 7 days after grafting).…”

“…If longer nerve segments were used as grafts, the nerve regeneration would be less successful in the distal half of the graft, regardless of whether the grafts were treated by freezing or not, because Schwann cell basal laminae of cryo-treated grafts can usually survive only up to 20-30 days after grafting (OSAWA et al, 1986). Thus, it is believed that the maximum effective length of the graft would be about 2-3 cm based on the evidence that axons regenerate approximately 1 mm per day.…”

Morphological Variations in Brachial Plexus of Beagle Dogs: Evaluation of Utility as Sources of Allogeneic Nerve Grafts

“…To overcome this difficulty, we attempt to perform frozen allogeneic nerve grafts [5] in dogs. No immunosuppressive reagents are required with this method, and successful axonal regeneration and myelination has been confirmed by electron microscopy in mice [13], rats [14], rabbits [20], dogs [6] and monkeys [19]. Given this morphological evidence, reasonable functional recovery appears likely.…”