Effect of lipid-hydroperoxide-induced oxidative stress on vitamin E, ascorbate and glutathione in the rabbit retina

Background: It is possible that oxidative stress causes several retinal diseases. However, the natural biogenic role of antioxidants in the retina is not clear. Purpose: This study investigates the change in concentration of vitamin E ( VE), ascorbate and glutathione ( GSH) in the retina following vitreous injection of 600 mu g 18: 2 linoleic acid hydroperoxide ( LHP) in male New Zealand rabbits. Method: LHP was injected above the retinal surface. The animals were sacrificed and the eyes enucleated before LHP injection, 1, 3, 6, 12, 24 h and 4 and 7 days after LHP injection. Retinas were removed, VE and ascorbate measured by HPLC, and GSH determined by a fluorometric method. Results: The concentration of VE in the retina decreased from pretreatment levels of 154.6 +/- 29.7 nmol/ g wet weight ( n = 7) and was lowest at 6 h ( 61.1 +/- 18.1 nmol/ g wet weight, n = 4, p < 0.05), then increased gradually, returning slowly to pre- LHP levels by 7 days. The concentration of ascorbate in control retinas decreased at 6 h from pretreatment levels of 7.33 +/- 0.93 mu mol/ g wet weight n = 7) to 2.74 +/- 0.16 mu mol/ g wet weight ( n = 4, p < 0.05) and returned to pretreatment levels rapidly by 24 h after injection. The concentration of GSH in retinas decreased from baseline levels of 109.53 +/- 8 8.19 mu g/g wet weight ( n = 9), was lowest at 12 h (72.40 +/- 11.17 mu g/ g wet weight, n = 5, p ! 0.05) and returned to pretreatment levels by 7 days. Conclusion: The results suggest that intravitreous LHP injection is a contributor to oxidative stress in the rabbit retina by causing a reduction in antioxidant capacity. Copyright (c) 2007 S. Karger AG, Basel.