Permeability of cerebral blood vessels in experimental allergic encephalomyelitis studied by radioactive iodinated bovine albumin

Abstract

Permeability of the cerebral blood vessels in experimental allergic encephalomyelitis (EAE) was studied. Iodinated radioactive bovine albumin and the autoradiographic method were used to assess the changes of permeability. Under normal conditions, the cerebral blood vessels are impermeable to the molecules of the albumin with the exception of the choroid plexus and the hypothalamus. Other regions, such as area postrema, were not studied. In the initial stage of EAE the inflamed blood vessels become permeable to albumin. In chronic animals, blood vessels with signs of inflammatory changes do not show increased permeability. In acute animals, certain blood vessels with signs of inflammatory changes may not show increased permeability. In many instances in acute animals, increased permeability was observed around blood vessels without any signs of inflammation. These last findings were interpreted to indicate that either [1] the primary lesion of the vessel wall may be one of the earliest phenomena leading to the full picture of EAE or [2] radioactive cerebrospinal fluid alone can penetrate the normal blood vessels deep into the brain tissue.