[Changes in the perineurium in experimental allergic polyneuritis].

The perineurium performs the role of a diffuse neurotissue barrier, protecting the nervous fibres from extra neuronal pathological processes. The changes in the cellular layers of the perineurium in experimental allergic polyneuritis appear secondarily and are directly connected with the severity and localization of the demyelinating process. As a result of a developing demyelinization in the foci of allergic inflammation there is an accumulation of biologically active substances which lead to disturbances of permeability and the intactness of cellular layers of the perineurium. In its turn this leads to the proliferation of a protein exudate from the endobeurium into its intracellular spaces. The dystrophic changes were in the form of large vacuoles, spaces, lacunes of an incorrect form filled with proteins and a large amount of lysosome-like bodies. The cell nuclei were subjected to pycnosis and perinuclear swelling. In the other 3-5 layers there were only processes of a reactive character: a swelling of the cytoplasma, an enlargement of the cysterns in the endoplasmatic reticulum, an increase of the amount of free ribosomes and pynocytic vesicles.