The perineurial and blood-nerve barriers in experimental diabetes.

The permeabilities of the blood-nerve barrier and the perineurial barrier were investigated in alloxan and streptozotocin diabetic rats and in the mutant diabetic mouse [C57BL/Ks(db/db)]. In the mouse model both fluorescence and electron microscopic techniques were employed using Evans blue albumin (EBA) and horseradish peroxidase (HRP), respectively, as exogeneous tracers. In the rat models only HRP was used. Tracers were applied locally around the sciatic nerve in order to investigate the perineurial barrier, and systemically to detect changes in the blood nerve barrier. None of the models was found to show increased permeability across either of the barriers.