Neuronal Quantification in Cold-Preserved Nerve Allografts and Treatment with FK-506 Through Osmotic Pumps Compared to Nerve Autografts

ABSTRACT Nerve regeneration across nerve autografts was compared to cold-preserved nerve allografts and treatment with FK-506. The tibial branch of the rat sciatic nerve was transected and immediately repaired with nerve autografts and allografts. FK-506 was administered for 4 weeks through osmotic pumps to different groups of both auto- and allograft cases. The nerves of two allografted groups were preserved with University of Wisconsin Cold Storage Solution (UWCSS) for 3 weeks. Quantification of retrograde-labelled motoneurons and axonal counts was performed. Nerve regeneration through nerve allografts treated with FK-506 or UWCSS was similar to the regeneration obtained when non-treated nerve autografts were used. However, there was no additive effect of the two treatments, and neither FK-506 nor UWCSS improved the number of gamma motoneurons. Both UWCSS and FK-506 administration with osmotic pumps was effective in improving nerve regeneration in allografts, achieving a level comparable to that obtained in non-grafted control cases.