Peripheral nerve changes in thiamine deficiency and starvation. An electron microscopic study.

Electron microscopic investigations on sciatic and plantar nerves of thiamine deficient and starved rats show a distally pronounced axonal degeneration. The changes are present in starved and thiamine deficient animals, but the deficient animals are more severely affected. The earliest alterations consist of an increase of mitochondria and a proliferation of vesicular elements of the endoplasmic reticulum. They are followed by loop formations of the axon membrane, clustering and disintegration of neurotubules and neurofilaments, axonal shrinkage and finally myelin disruption. The distal accentuation of the early changes indicates a dying-back mechanism of axonal degeneration.