Effect of Lipid-Hydroperoxide-Induced Oxidative Stress on Vitamin E, Ascorbate and Glutathione in the Rabbit Retina

Abstract

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 µg 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 µmol/g wet weight (n = 7) to 2.74 ± 0.16 µmol/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 ± 8.19 µg/g wet weight (n = 9), was lowest at 12 h (72.40 ± 11.17 µg/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.