VASCULAR-PERMEABILITY CHANGES ASSOCIATED WITH EXPERIMENTALLY-INDUCED FACIAL-NERVE LESIONS IN THE RABBIT

Changes in vascular permeability to sodium fluorescein following exper imentally induced nerve lesions were examined in the rabbit facial ner ve. Sodium fluorescein was injected intravenously as a permeability tr acer and then localized by fluorescence microscopy. In control nerves, endoneurium showed only slight fluorescence while intense fluorescenc e was observed in the epineurium and perineurium. In nerves demonstrat ing edema and Wallerian degeneration, endoneurium was found to have an increased accumulation of tracer. This increased endoneurial vascular permeability in facial nerve lesions may explain nerve enhancement se en in gadolinium-enhanced magnetic resonance imaging in patients with facial nerve paralysis.