Structural impairments in optic nerve of diabetic rats ameliorated with the aldose reductase inhibitor.
Structural impairments of optic nerve fibers in the streptozotocin-induced diabetic rat were investigated using morphometric analysis. The effect of aldose reductase inhibitor (ARI) on abnormalities in myelinated nerve fibers was also evaluated. Three months after the induction of diabetes, loss of body weight and significantly elevated levels of serum glucose were observed. Light microscopic examination revealed that the mean size of the optic nerve in the diabetic rat remained unchanged. Electron microscopic morphometry showed the significantly smaller cross-sectional size of axons and myelin but no change of myelinated fiber number. Reductions of myelinated fiber size was especially remarkable in the larger fibers. ARI treatment improved structural abnormalities without any changes in body weight and blood glucose level. Reduction of axon size and myelin/axon ratio was completely inhibited by ARI treatment. These findings suggest that structural impairment may contribute to the abnormalities of psychophysical and electrophysiological measurements detected in diabetes. Moreover, ARI treatment, which can improve the polyol metabolism, may have a beneficial effect on optic nerve impairment in diabetes.
Ino-ue
M
M
Department of Ophthalmology, School of Medicine, Kobe University, Kobe, Japan.
Yokogawa
H
H
Yamamoto
M
M
Naka
H
H
Kuriyama
H
H
D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors*; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000473:pathology*; D003929:Diabetic Neuropathies / Q000473:pathology*; D008854:Microscopy, Electron; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D009901:Optic Nerve Diseases / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000449:Aldehyde Reductase