Prevention of oxidative damage to lens by caffeine.

PURPOSE: The primary objective of this study was to examine the possibility of inhibiting oxidative damage to the lens in vitro by caffeine. METHODS: Oxidative damage was inflicted by incubating mouse lenses in Tyrode medium containing 0.1 mM Fe(8)Br(8), an iron complex soluble in aqueous medium. Parallel incubations were conducted in the presence of caffeine (5 mM). RESULTS: Lenses incubated in the medium containing Fe(8)Br(8) undergo oxidative stress, as evidenced by the inhibition of Na(+)-K(+) ATPase-driven rubidium transport and the loss of tissue glutathione and ATP. These effects were prevented in presence of caffeine. That the effects are due to the oxyradicals produced was ascertained further by parallel studies with Tempol (5 mM), a well-known scavenger of reactive oxygen species (ROS) with its activity being more pronounced with hydroxyl radicals as compared to other ROS. CONCLUSIONS: Caffeine was found to be effective in preventing oxidative stress to the lens induced by iron under ambient conditions. The protective effect is attributable to its ability to scavenge ROS, particularly the hydroxyl radical.