A rodent model of organophosphorus-induced delayed neuropathy: distribution of central (spinal cord) and peripheral nerve damage.

Central and peripheral nerve fibre damage has been produced in Long-Evans hooded male rats with tri-ortho-cresyl phosphate. Animals were dosed by gavage with intermittent or daily amounts of the organophosphate and examined after 2, 6, 12, 18 and 24 weeks. The distribution of central nervous system (spinal cord) damage and the differential vulnerability among various peripheral nerves supported a "dying-back' classification for the neuropathy. Giant axonal swellings, containing massive accumulations of smooth endoplasmic reticulum, hallmarked the neuropathy. In spite of severe neurological damage the animals displayed only moderate functional disturbances. These findings have shown that the rat is highly sensitive to the structural damage caused by organo-phosphates, although resistant to the ataxia.