Studies on vascular permeability in peripheral nerves

Summary Permeability changes of vasa nervorum and exudation of serum albumin in a nutritional peripheral neuropathy induced by isonicotinic acid hydrazide (INH) in rats were studied by menas of fluorescence microscopic tracing of intravenously injected albumin tagged with Evans blue or with fluorescein isothiocyanate.All rats given INH for fourteen days which developed histologically demonstrable neuropathy also showed abnormal vascular permeability and exudation of the albumin conjugate into the endoneurium. Once outside the blood vessels the conjugate had a predilection for spreading in the endoneurial interstices along the nerves.Thus, like traumatic peripheral neuropathies, this nutritional neuropathy is associated with permeability changes of vasa nervorum and exudation of serum albumin in the endoneurium. The simultaneous occurrence of nerve fibre lesions and permeability changes of vasa nervorum indicates that these two phenomena are in some way related to each other.Supported by grants from the Swedish Multiple Sclerosis Society and from the Swedish Medical Research Council, Project B 68-12X-82-04.