[Effect of oxythiamine on rat peripheral nerve. --Morphological changes in sciatic nerve and plantar nerve of thiamine deficiency-- (author's transl)].

Morphological changes in rat sciatic nerve (SN) and plantar nerve (PN) induced by a thiamine deficient diet (TDD) and administration of oxythiamine (OT: 4 mg/100 g X 6 days) were observed, and thiamine (T) levels in rat nerve were simultaneously determined. Body weight gain ratio in rats which received OT fed a TDD (OTD group) was much reduced, and anorexia and ataxia were recognized in this group. Rats fed a regular diet, whose weights were restricted to be the same as those in the OTD group (EWC group), showed the symptoms of starvation. T levels of the SN and PN in the OT group, OTD group, and rats fed a TDD (TDD group) were reduced, but in the EWC group, T levels were the same as those in the control group (C group). There were myelin folds and myelin oboids in the EWC group, and these were recognized before axonal degeneration. In the TDD group, an increase in the number of mitochondria (Mit) was seen in the myelinated axon (MAx). In the TDD group, an increase in the number of mitochondria (Mit) was seen in the myelinated axon (MAx). In the OT and OTD groups, axonal degeneration (increase in the number of Mit, appearance of degenerated Mit, axonal shrinkage, and disappearance of neurofilament and neurotubule) was observed in the MAx. Degeneration of the MAx caused by TDD and OT was more severe in the PN than in the SN. Since these changes progressed from the peripheral nerve to the centripetal one, these changes in OTD group might be dying-back polyneuropathy.