Abstract
The aim of this study was to investigate whether curcumin and aminoguanidine (AG) prevent selenium-induced cataractogenesis in vitro. On postpartum day 8, transparent isolated lens were incubated in 24 well plates containing Dulbecco's Modified Eagle Medium (DMEM). Isolated lens of group I were incubated with DMEM medium alone. Group II: lenses incubated in DMEM containing 100microM sodium selenite; group III: lenses incubated in DMEM containing 100microM sodium selenite and 100microM curcumin; group IV: lenses incubated in DMEM containing 100microM sodium selenite and 200microM curcumin; group V: lenses incubated in DMEM containing 100microM sodium selenite and 100microM AG; group V: lenses incubated in DMEM containing 100microM sodium selenite and 200microM AG. On day 12, cataract development was graded using an inverted microscope and the lenses were analyzed for enzymic as well as non-enzymic antioxidants, lipid peroxidation (LPO), nitric oxide (NO), superoxide anion (O(2)(-)) and hydroxyl radical generation (OH) and inducible nitric oxide synthase (iNOS) activity by Western blotting and RT-PCR. All control lenses in group I were clear (0). In groups II and III, all isolated lenses developed cataract with variation in levels (+++ or ++), whereas isolated lenses from groups IV, V and VI were clear (0). In agreement to this, a decrease in antioxidants and increased free radical generation and also iNOS expression were observed in selenium exposed lenses when compared to other groups. AG (100microM) was found to be more effective in anti-cataractogenic effect than curcumin (200microM). Curcumin and AG suppressed selenium-induced oxidative stress and cataract formation in isolated lens from Wistar rat pups, possibly by inhibiting depletion of enzymic as well as non-enzymic antioxidants, and preventing uncontrolled generation of free radicals and also by inhibiting iNOS expression. Our results implicate a major role for curcumin and AG in preventing cataractogenesis in selenite-exposed lenses, wherein AG was found to be more potent.
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