Kynurenine-induced photo oxidative damage to lens in vitro: protective effect of caffeine.

Photochemical generation of reactive species of oxygen in the lens and aqueous and consequent physiological damage to the tissue has been implicated in the genesis of human cataracts. The present studies were undertaken to examine the feasibility of possible prevention of such damage to the lens initiated by UV activation of kynurenine, a well-known photosensitizer in the human lens. The studies were done by organ culturing intact mouse lenses in medium containing kynurenine and exposed to UVA. Tissue damage was assessed by the inhibition of its ability to carry active transport of rubidium ions and the associated decrements in the levels of GSH and ATP. These deleterious effects were significantly prevented by caffeine, an alkaloid present in many common beverages and known to chemically deactivate the said oxygen derivatives. Further studies on the pharmacological significance of the findings are hence in progress.