Experimental study on segmental demyelination in tellurium neuropathy.

Weanling rats fed a diet containing elemental tellurium became paralyzed of their hind legs based on segmental demyelination of the sciatic nerves. Recovery from the paralysis and remyelination took place despite continued receiving of the diet. The author could divide the process of demyelination and remyelination into four stages (Stage I-IV). The earliest changes were observed in the Schwann cell cytoplasm in which the Golgi complex revealed shrinkage, fragmentation and vacuolation. These changes soon involved the endoplasmic reticulum (Stage I). Degenerative changes of the Golgi complex and the endoplasmic reticulum were considered to disturb the active Schwann cell metabolism inhibiting the synthesis and maintenance of the myelin, resulted in disintegration and destruction of the myelin sheath (Stage II). Schwann cells proliferated around the demyelinated axons extending numerous elongated processes (Stage III). When remyelination began, only one simple shaped Schwann cell was associated with the axon. Remyelinated fibers were generally small in size, which was considered to be related to the formation of the short segments as well as to the Schwann cell proliferation (Stage IV).