Time course of blood nerve barrier reconstitution after sectioning: implications for xenograft studies

The time course of blood-nerve barrier recovery in mouse nerves was studied after proximal and distal segmental sciatic sections. Transfer constants for uptake of isotopically labeled sucrose and urea were determined. Sectioned segments were examined ultrastructurally. Marked alterations in isotope uptake for 2 months with gradual restoration of blood-nerve barrier by 6 months was found. Ultrastructure of sectioned segments showed increased numbers of perineurial compartments. Human nerve xenografts to immunosuppressed animals remain hypomyelinated for 6 months which may be related to damage to the blood-nerve barrier.