Effects of chronic vitamin E deficiency on the nervous system of the rat.

Light- and electron-microscopic studies were carried out on the central nervous system (CNS) and the peripheral nervous system (PNS) of vitamin E-deficient rats. Extensive axonal degeneration and dystrophic changes were observed in posterior columns and their medullary relay nuclei, respectively. The changes were more prominent in gracile tracts and nuclei than cuneate tracts and nuclei. Alteration in the PNS were less severe than those in the CNS. The posterior roots and sciatic nerves showed only a mild degree of axonal degeneration, while more distal segments of axons in s.c. nerves, in cutaneous sensory corpuscles, and in muscle spindles of hind paws were more severely affected. The neurons in the dorsal root ganglia showed only accumulation of lipofuscin. The above findings in chronic vitamin E deficiency indicate that (a) in addition to the degeneration of central extensions of sensory neurons, their peripheral axons are also affected, (b) the distribution of lesions is similar to those seen in distal axonopathies or a "dying back" process.