A TECHNICAL APPROACH TO THE EVALUATION OF GLUCOSE-OXIDATION - IMPLICATIONS FOR DIABETIC CATARACT

Oxidative stress has recently been involved in a number of diseases in cluding development of diabetic cataract. If hyperglycemia is the rele vant factor in diabetes, then it is reasonable to assume that under ph ysiological conditions glucose may be toxic, The mechanisms involved i n such a type of glucose 'toxicity' are still poorly understood but ma y involve glucose autoxidation. In this study we discuss a new methodo logical approach to the evaluation of glucose-induced oxidative damage to bovine lens membranes. The method is based on the incorporation of a fluorescent probe (parinaric acid) into lens membranes. The oxidati ve degradation of the probe is evaluated by monitoring its fluorescenc e decrease. It was possible to show that glucose may induce oxidative damage in the presence of trace amounts of transition metals. Furtherm ore, the data obtained by monitoring oxidative degradation of parinari c acid could be related to the amount of thiobarbituric acid-reactive substances formed under identical periods of time. The technique was s hown to be reproducible, straightforward and highly sensitive as compa red to other classical methods. Moreover, this methodological approach allows not only the evaluation of the extension of oxidative stress i nflicted upon lens membranes but also the evaluation of the antioxidan t effect of various compounds including some drugs with a potential an ticataractogenic effect.