Retinitis pigmentosa / oxidative damage / Antioxidants

Discussion in 'Optometry Archives' started by ironjustice, Jul 27, 2006.

  1. ironjustice

    ironjustice Guest

    Antioxidants reduce cone cell death in a model of retinitis pigmentosa.
    Komeima K, Rogers BS, Lu L, Campochiaro PA
    Proc Natl Acad Sci U S A. 2006 Jul 25; 103(30): 11300-5

    Retinitis pigmentosa (RP) is a label for a group of diseases caused by
    a large number of mutations that result in rod photoreceptor cell death
    followed by gradual death of cones. The mechanism of cone cell death is
    uncertain. Rods are a major source of oxygen utilization in the retina
    and, after rods die, the level of oxygen in the outer retina is
    increased. In this study, we used the rd1 mouse model of RP to test the
    hypothesis that cones die from oxidative damage. A mixture of
    antioxidants was selected to try to maximize protection against
    oxidative damage achievable by exogenous supplements; alpha-tocopherol
    (200 mg/kg), ascorbic acid (250 mg/kg), Mn(III)tetrakis (4-benzoic
    acid) porphyrin (10 mg/kg), and alpha-lipoic acid (100 mg/kg). Mice
    were treated with daily injections of the mixture or each component
    alone between postnatal day (P)18 and P35. Between P18 and P35, there
    was an increase in two biomarkers of oxidative damage, carbonyl adducts
    measured by ELISA and immunohistochemical staining for acrolein, in the
    retinas of rd1 mice. The staining for acrolein in remaining cones at
    P35 was eliminated in antioxidant-treated rd1 mice, confirming that the
    treatment markedly reduced oxidative damage in cones; this was
    accompanied by a 2-fold increase in cone cell density and a 50%
    increase in medium-wavelength cone opsin mRNA. Antioxidants also caused
    some preservation of cone function based upon photopic
    electroretinograms. These data support the hypothesis that gradual cone
    cell death after rod cell death in RP is due to oxidative damage, and
    that antioxidant therapy may provide benefit.

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    ironjustice, Jul 27, 2006
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