Diabetes, Vol 45, Issue 1 56-59, Copyright © 1996 by American Diabetes Association
Galactosemic neuropathy in transgenic mice for human aldose reductase
S Yagihashi, S Yamagishi, R Wada, K Sugimoto, M Baba, HG Wong, J Fujimoto, C Nishimura and Y Kokai
Department of Pathology, Hirosaki University School of Medicine, Japan.
We studied the functional consequences of an enhanced polyol pathway
activity, elicited with galactose feeding, on the peripheral nerve of
transgenic mice expressing human aldose reductase. Nontransgenic littermate
mice were used as controls. With a quantitative immunoassay, the expression
level of human aldose reductase in the sciatic nerve was 791 +/- 44 ng/mg
protein (mean +/- SE), about 25% of that in human sural nerve. When the
transgenic mice were fed food containing 30% galactose, significant levels
of galactitol accumulated in the sciatic nerve. Galactose feeding of
nontransgenic littermate mice led to a 10-fold lower accumulation of
galactitol. Galactose feeding for 16 weeks caused a significant and
progressive decrease in motor nerve conduction velocity in transgenic mice
to 80% of the level of galactose-fed littermate mice, which was not
significantly different from that of galactose-free littermate mice. A
morphometric analysis of sciatic nerve detected > 10% reduction of mean
myelinated fiber size but no alterations of myelinated fiber density in
galactose-fed transgenic mice compared with other groups. The functional
and structural changes that develop in galactose-fed transgenic mice are
similar to those previously reported in diabetic animals. The results of
these studies suggest that transgenic mice expressing human aldose
reductase may be a useful model not only for defining the role of the
polyol pathway in diabetic neuropathy but also for identifying and
characterizing effective inhibitors specific for human aldose reductase.