CONSUMPTION OF A HIGH-GALACTOSE DIET INDUCES DIABETIC-LIKE CHANGES INTHE INNER-EAR

Diabetes mellitus is a disease that affects multiple organ systems, In our laboratory it has been shown that there is a significant loss of outer hair cells in genetically;diabetic rats. Galactosemia can also p roduce diabetic-like changes, This study was performed to demonstrate whether these changes also occur in the cochlea. Three groups of Sprag ue-Dawley rats were used and fed either a control diet, a 50% galactos e diet, or a 50% galactose diet with the addition of an aldose reducta se inhibitor, After 5 months the animals were killed, and the cochleas were removed, fixed, and stained, Diabetes-induced damage was assesse d by counting the hair cells and calculating the neuroganglion cell de nsity, The histopathologic changes induced by galactose were manifeste d as outer hair cell loss and a decrease in neuroganglion cell density . Control animals had the least amount of hair cell loss and the great est neuroganglion cell density of all three groups, Galactose-only ani mals demonstrated the most pronounced changes in both hair cell loss a nd neuroganglion cell degeneration; however, only changes of neurogang lion cell density in the basal turn were significant, the addition of an aldose reductase inhibitor provided inconclusive results in both ha ir cell determination and neuroganglion cell density; however, general ly the inhibitor partially prevented the damage produced by galactose, These results suggest that a high-galactose diet can induce diabetic- like changes in the cochlea.