A new approach against sugar cataract through aldose reductase inhibitors

Aldose reductase inhibition is one of the therapeutic strategies that has b een proposed to prevent or ameliorate long term diabetic complications incl uding retinopathy and sugar cataract. Rats were fed with a galactose rich d iet and the aldose reductase inhibitor Tolrestat was topically delivered by ocular instillation. The levels of lens aldose reductase activity, galacti tol and the onset of cataract were evaluated during and after treatment wit h the inhibitor. Topical application of 1-3 % Tolrestat (10 mu l) four times daily resulted, after 9 days, in a significant decrease in the enzyme activity. Well after interrupting treatment with the drug, the enzyme activity remained impaire d and galactose induced cataract was prevented. Our findings may represent the basis for therapeutic plans to prevent sugar cataract by long term cycl ic treatments with aldose reductase inhibitors, with reduction in drug dose s and side effects. (C) 1999 Academic Press.