Ultrastructural cytochemistry: effect of Sorbinil on arylsulfatases in cataractous lenses

We have demonstrated an increase in activity of arylsulfatase A and B during galactose induced cataract development in rats. Our recent investigation shows that acid phosphatase activity, which increases substantially during galactose cataract development in rats, could be contained to near normal level if Sorbinil, an aldose reductase inhibitor, was fed along with galactose to the rat. We have observed that the activity of other lysosomal enzymes, arylsulfatase A and/or B, also increases during galactose cataractogenesis. In the present report, we provide information with regards to the effect of Sorbinil on the activity of these enzymes during cataractogenesis. A modified Hopsu-Havu and Helminen method (1974) with p-nitrocatecholsulfate as substrate was used for localization of both arylsulfatase A and B; and the method of Hara et al. (1979) was utilized to obtain quantitative data on the level of arylsulfatase A and B activity. Ultrastructural cytochemistry shows that arylsulfatase activity in all lenses was primarily localized in epithelial cells in lysosomes with very little or no activity in cortical fibers. The number of arylsulfatase positive lysosomes and the activity level of these enzymes increased with the progression of cataract development. Galactose induced damage to lens morphology and increase in activity of arylsulfatase A and B was inhibited by inclusion of 50mg/Kg (diet) Sorbinil in the galactose containing cataractogenic diet. However, Sorbinil had no significant effect on the enzyme activity following the establishment of mature cataracts.