Abstract
Abstract: :
Purpose:To define the mechanisms involved in cataract development after ocular trauma or inflammation. The neutrophil is the main cell type involved in the acute phase of intraocular inflammation. Activated neutrophils produce proteases and metabolites of reactive oxygen species (superoxide anion, hydrogen peroxide, hypochlorous acid and hydroxyl radicals). This study investigates the effect of neutrophil immune response products, proteases and reactive oxygen species on lens protein. Methods:The capsule was removed from porcine lens and the cortex and nucleus exposed to lysozyme and collagenase, reactive oxygen species and saline (controls) in three different experiments. In the first, groups of 6 lens proteins were exposed during four hours to: saline solution, 0.6mM of CuSO4.5H2O, 17 mM of H2O2, 0.6mM of CuSO4.5H2O and 17 mM of H2O2, PBS, and 506 units of lysozyme. In the second step, lens protein in groups of 2 was exposed over 24hours to: saline, 0.6mM of CuSO4.5H2O, 17 mM of H2O2, PBS, 506 units of lysozyme, 7100 units of collagenase, 400mM of xanthine and 50mU of xanthine oxidase, and 0.6mM of CuSO4.5H2O and 17 mM of H2O2. In the third part of the study, lens protein was exposed to different concentrations of CuSO4.5H2O, CuSO4.5H2O and 17 mM of H2O2, and collagenase. Lens damage was graded by inspection at 10 min, 4 hours, 8 hours and 24 hours. Results:Lens protein exposed to saline, PBS, Lysozyme and lower concentrations of CuSO4.5H2O (0.006mM), with or without H2O2 up to 24h failed to develop opacity. CuSO4.5H2O at 0.6mM and 0.06mM with or without 17 mM of H2O2 presented with similar opacity at 1,4 and 8hours, but only in the group with H2O2 did the opacity progress after 8 hours. The lens exposed to collagenase did not develop opacity, but were dissolved by 50% over 24 hours. Conclusion:The reactive oxygen species produced by CuSO4.5H2O stimulated opacity in the lens protein. This effect was enhanced by increased concentration and the addition of H2O2. Collagenase produced a reduction in lens size, but did not produce lens opacification.
Keywords: 338 cataract • 504 oxidation/oxidative or free radical damage • 437 inflammation