Regeneration through long nerve grafts in the swine model

Abstract

We investigated regeneration across a long nerve defect in the swine model to study extensive neural loss and long nerve gap. Most experiments have been conducted in the rodent model that, while an appropriate immunological model, only allows short nerve gaps to be studied. Twelve outbred swine received either an 8-cm ulnar nerve autograft or an allograft without immunosuppression. At 6 and 10 months, histomorphometry of the autografts demonstrated excellent nerve regeneration, while very poor regeneration was noted across the allografts. This confirmed that 8 cm are an adequate challenge independent of the spontaneous regeneration potential of axons seen in rodents. The swine ulnar nerve graft model causes minimal morbidity and will now be used with immunological manipulation of inbred animals.

Reconstruction of Critical Nerve Defects Using Allogenic Nerve Tissue: A Review of Current Approaches

“…Thus, on a 2.8 cm sciatic nerve defect, regeneration after surgical reconstruction by the collagen-based nerve graft was inferior to the allograft group, and the isograft control. Basically this is in agreement with the previously reviewed pre-clinical studies [30,[38][39][40][41][42][43]45,[47][48][49][50]. Beside this, there is still a lack of evidence that processed allograft can perform superior to other marketed materials.…”

Effect of FK506 on Peripheral Nerve Regeneration Through Long Grafts in Inbred Swine

“…The original group size of 8, although small, was based on prior experience with large-animal models of nerve regeneration and immunologic assays. 12,[37][38][39] However, the unanticipated loss of 3 of these animals resulted in an underpowered analysis. Collectively, the data do suggest that FK506 therapy results in durable neuroenhancement across long nerve grafts.…”

“…40 -44 The significant interanimal variability observed histologically in this study is consistent with prior experience in miniature swine. 37,38 For example, autografts in the untreated group had notably different autograft regeneration despite similar health and weight gain. At time of harvest, neither nerve was noted to have avulsion, atypical neuroma formation, or other evidence of technical failure.…”

Survival of Long Nerve Allografts Following Donor Antigen Pretreatment: A Pilot Study

“…However, given the lengthy time required for regeneration across long grafts and the high maintenance and expense of caring for swine, we used our previously reported study as a basis for comparison between the immunosuppressed allografts and control autografts and unimmunosuppressed allografts. 9 In keeping with these limitations, we did not find other studies utilizing swine in single tissue, nerve allograft transplantation. Other large animal models that have been used in isolated peripheral nerve allograft transplantation studies include dog, sheep, and primate.…”