MODELING CORTICAL CATARACTOGENESIS .1. INVITRO EFFECTS OF GLUCOSE, SORBITOL AND FRUCTOSE ON INTACT RAT LENSES IN MEDIUM-199

Abstract

After 2 days, lenses with intact capsules from adult rats remained clear when incubated in medium 199 with a normal glucose concentration but showed opacities when the level of glucose was increased up to 10 times normal. Scanning electron microscropy of the fixed lenses demonstrated globular degeneration in the visibly opaque lenses. The depth of degeneration and opacity increased as a function of the glucose concentration in the medium. In glucose-induced cataracts, as in other types of cortical cataracts, opacity and globular degeneration of the lens appear associated. Sorbitol (but not fructose) induced globular degeneration and lens opacities. There may be a mechanism of cataractogenesis other than osmosis. The higher risk of cataracts in persons with controlled diabetes may be related. In vitro a lower concentration of glucose in medium 199, 8.9 mM (1.6 times the normal level), with 96 h of incubation was as effective as the minimum concentration capable of causing cataracts, 11.1 mM (2 times the normal level), with 24 h of incubation.