THE EFFECT OF PHOTOCHEMICAL STRESS UPON THE LENSES OF NORMAL AND GLUTATHIONE PEROXIDASE-1 KNOCKOUT MICE

This communication investigates the effect of oxidative stress upon th e lenses of young normal and glutathione peroxidase-l (GSHPx-1) Knocko ut mice. Both normal and knockout lenses have similar biochemical and morpholigical characteristics and the elimination of GSHPx-1 only decr eases slightly the ability of the lens to degrade H2O2. Examination of the effect of a 4 hr photochemical stress on morphological characteri stics indicates that there is comparable damage in the normal and knoc kout lenses in the epithelial and bow regions while the posterior regi on remains normal. However, at 24 hrs post-insult, the normal lenses a ppear to recover somewhat in the bow region while the knockout bow and posterior regions have extensive damage. In contrast to the morpholog ical data, the biochemical parameters (C-14)choline transport and (H-3 )thymidine incorporation are affected to a somewhat greater extent in the knockout lenses than in normal lenses. While both of these paramet ers are further affected in the 24 hr post-insult period, there is no further change in the relative effects upon normal and knockout lenses . Non-protein thiol is affected in a similar manner in both lens types . The effect upon biochemical parameters of tertiary butyl hydroperoxi de (TBHP) insult was similar to H2O2 and photochemical stress. The ove rall conclusion is that young GSHPx-1 knockout lenses handle oxidative stress somewhat less effectively than comparable normal lenses but no n-stressed knockout lenses appear normal. These results differ from ob servations reported by Reddy et al. (1997) under somewhat different co nditions. (C) 1998 Academic Press.