AGE-DEPENDENT LENS CHANGES IN GALACTOSE-FED DOGS

Aldose reductase initiated sugar cataract formation in 9-month old gal actose-fed dogs has been documented to progress from an accentuation o f lens sutures (1 month after initial feeding) to the appearance of co rtical vacuoles (3 months), cortical opacities (4-6 months) and eventu ally the progressive formation of a clear zone at the cortical equator ial regions of the cataractous lenses (> 12 months). Here, the effect of age on the onset and degree of sugar cataract formation has been in vestigated in beagles fed a 30% galactose diet starting at 2, 6, and 2 4 months of age. Cataract formation was monitored by slit lamp and ret roillumination microscopy. Compared to 9-month old dogs, cataract form ation in the younger dogs was more rapid and the lens changes were mor e severe. In the 2-month old group of dogs, galactose-feeding resulted in a rapid formation of dense cataracts which began to resorb after 1 06 days of galactose feeding with only opaque nuclear remnants remaini ng after eight months. These changes were mirrored by age-dependent re ductions of lenticular NADPH-dependent reductase activity. (C) 1997 Ac ademic Press Limited.