QUANTITATIVE-ANALYSIS OF MYELINATED NERVE-FIBERS OF PERIPHERAL-NERVE IN STREPTOZOTOCIN-INDUCED DIABETES-MELLITUS

The purpose of this study was to examine morphometric changes of myeli nated fibers in early stages of experimental diabetes mellitus. Adult male Wistar rats aged 17 wk were used in this study. Diabetes mellitus was induced by streptozotocin. Samples of common peroneal nerve from diabetic rats (4 and 8 wk after induction of diabetes mellitus) and ag e-matched control animals were removed and processed. The semithin cro ss sections were stained with toluidine blue and used for myelinated f iber computer-aided morphometric analysis. There were no significant c hanges in diabetic animals after 4 wk duration of the disease. There w as significant reduction in myelinated nerve fiber caliber in diabetic rats 8 wk after induction of diabetes as compared to age-matched cont rols. There was no significant reduction of axonal area in this group of diabetic rats, so diminution of fiber area was caused predominantly by reduction of myelin sheath area. The study demonstrates that the i nduction of diabetes mellitus in rat by streptozotocin is accompanied by early changes of the morphometric indices of myelinated nerve fiber s of peripheral nerve.