Schwann cell abnormalities in 2,5-hexanedione neuropathy.

Distinctive cytoplasmic alterations of Schwann cells were observed by electron microscopy in rats and mice with peripheral neuropathy induced by chronic exposure to 2,5-hexanedione. Pronounced enlargement of Schwann cells was due to accumulation of 100 angstrom cytoplasmic filaments and endoplasmic reticulum and was most often observed after 12--15 weeks exposure to 2,5-hexanedione. Examination of teased nerve fibres revealed segmental demyelination and remyelination involving axons of normal diameter as well as giant axons. The filament disorder induced by 2,5-hexanedione administration is not limited solely to axoplasmic contents. Possible mechanisms of demyelination are discussed and the changes are compared to those observed in human neuropathy for which 2,5-hexanedione appears to be the closest experimental model.