Peripheral neuropathy following prolonged exposure to streptozotocin-induced diabetes in rats: a teased nerve fiber study.

An experimental diabetic state was induced in rats by means of an injection of streptozotocin. A histological and histometric evaluation of randomly teased nerve fibers was applied to the common peroneal nerves of both diabetic and age- and weight-matched control rats. A long-term (6-12 months) exposure to the diabetic state was required for the demonstration of the following morphological changes: (1) splitting and notching of myelin sheaths, (2) decrease in the ratio of internodal length/internodal diameter, (3) widening of nodal gaps. This study showed that neurons of smaller caliber are preferentially affected after a prolonged period of the diabetic condition. Neurons of this size are representative of sensory and autonomic components, suggesting that the changes present in this model parallel the derangements of these constituents reported in the human diabetic with adult onset disease.