Experimental clioquinol intoxication in rats: abnormalities in optic nerves and small nerve cells of dorsal root ganglia.

Pathological abnormalities in the central (CNS) and peripheral nervous system (PNS) were produced in rats by daily administration of 300-400 mg/kg clioquinol for 7-40 days. The changes comprised axonal degeneration of optic nerve fibers and mitochondrial swellings in small nerve cells of dorsal root ganglia. There were occasional myelin splittings in the spinal nerve roots. No apparent changes were observed in the spinal cord or peripheral nerves. Similar changes were occasionally encountered to a lesser extent in control rats by restricting the diet and water to maintain the body weight comparable to the ranges of experimental animals. It seemed that not only clioquinol intoxication but nutritional deficiency also contributed, in part, to the production of these CNS and PNS abnormalities. The possibility of the presence of peripheral neuropathy in subacute myelooptic neuropathy is discussed.