Histological Properties of the Ischiadic Nerve in Rats Intoxicated by Organic Solvents

The incidence of neurophysiological disorders and polyneuropathies has been seen as a consequence of long-term occupational exposure to organic solvents. The aim of the study was to determine, and histologically quantify the changes in the sciatic nerves of the rats intoxicated by inhalation of organic solvents (toluene, xylene, n-butylacetate, acetone and white-spirit) in the concentrations of 3,000 ppm (6 hours a day, 5 days a week, except for week end during the period of 8 weeks). Initial changes, indicating toxic neuropathy, i.e. axonal degeneration, accompanied by accummulation of soft membrane neurofilaments, as well as of mitochondria, were percieved. This finding is based on the appearance of endoneural edema, more pronounced in the central parts of the bundle and subperineurally (light microscopy), while individual fibres (teased preparation) showed a focal, oval or round, tomaculum-like body myelin swellings, with compression on axons and sporadic degeneration. Electro-microscopy showed clear degenerative changes of myelin in the form of "tomaculous" reduplication of myelin lamellae, sometimes multiple within the whole circumference with compression on very atrophic axons and coagulation of organellae (neurofilaments and neurotubules, proliferated endoplasmic reticulum), as well as with miochondria accummulation in the Schwann cell cytoplasm in the paranodal region.