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C.K. M. Choy, P. Cho, I.F. F. Benzie; Ascorbate Concentration and Total Antioxidant Capacity in Porcine Cornea and Crystalline Lens . Invest. Ophthalmol. Vis. Sci. 2005;46(13):5405.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To investigate ascorbate and total antioxidant capacity levels in central and paracentral regions of cornea and crystalline lens. Methods: Central (4 mm diameter) and paracentral (2 mm) areas of cornea and crystalline lens from 15 freshly enucleated porcine eyes were collected. Ascorbate and total antioxidant capacity (as the FRAP value) were determined on individual homogenate filtrates. Results are expressed as mmol/g wet weight of tissue. Results: Mean±SD ascorbate and FRAP values of central cornea were 0.99±0.20 and 2.88±0.44 mmol/g, respectively. Values for both were significantly (P<0.001) higher than in paracentral cornea (13% and 18%, respectively). Mean±SD ascorbate and FRAP values of central crystalline lens were 1.06±0.18 and 4.60±0.81 mmol/g, respectively, which were 26% and 15%, respectively, lower than in paracentral lens (P<0.001). Ascorbate constituted >65% of the total antioxidant capacity of cornea, and ∼45% that of crystalline lens. Significant correlations (all P<0.01) were found between the ascorbate and FRAP values of cornea (central, r=0.796; paracentral, r=0.917) and crystalline lens (central, r=0.743; paracentral, r=0.635). Conclusions: Higher ascorbate concentration and total antioxidant capacity were observed along the visual axis of the cornea, in keeping with the likely role and active accumulation of antioxidants to prevent oxidative damage to the light–exposed central cornea. The paradoxically lower ascorbate and total antioxidant capacity of the central area of the lens may reflect photoxidative loss of antioxidants along the visual axis of the crystalline lens, as, after passing through the cornea, light is focused onto the central region of the crystalline lens. Further studies are warranted.
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