Morphometric analysis of autonomic neuropathology in the abdominal sympathetic trunk of the ketonuric diabetic Chinese hamster.

Fibers from the infradiaphragmatic portion of the sympathetic trunk of ketonuric diabetic Chinese hamsters were quantitatively analyzed by light and electron microscopy to determine frequency distribution and numerical density. Myelinated and unmyelinated fibers displayed a significant reduction in diameter which was exacerbated by increased duration of ketonuria. Mean numerical density of myelinated fibers was reduced whereas that of unmyelinated fibers was increased. The alterations in sympathetic nerve populations are believed to be a manifestation of previously observed demyelination and axonal degeneration. On the basis of axon diameter, it appeared that both visceral afferent and efferent fibers were affected. These data strongly suggest that autonomic neuropathology in the sympathetic trunk of the diabetic Chinese hamster may be a critical factor underlying gastrointestinal dysfunction.