Time course changes of oxidative stress markers in a rat experimental glaucoma model

Abstract

PURPOSE. To evaluate the relationship between oxidative stress arkers and increased intraocular pressure in experimental laucoma. METHODS. In vivo chemiluminescence (CL), total antioxidant apacity (TRAP), nitrite concentration (NC), and lipid peroxidation arkers (TBARS) were evaluated. Wistar rats (n = 18 for ach time point) underwent operation, and two episcleral eins were cauterized. ESULTS. Decreases of 22%, 35%, and 27% at 7, 15, and 30 days nd an increase of 22% at 60 days in CL were observed in laucomatous eyes. In optic nerve, TBARS values were 6.9 ± 0.5 nmol/mg protein (7 days), 9.4 ± 0.4 nmol/mg protein (15 ays), 18.0 ±1.2 nmol/mg protein (30 days), and 43.1 ± 5.3 nmol/mg protein (60 days) (control, 6.2 ± 0.4 nmol/mg protein; P < 0.001). NC was 37.0 ± 1.8 μM (7 days), 31.4 ± 1.2 μM (15 days), 39.6 ± 1.3 μM (30 days), and 40.0 ± 1.3 μM (60 days) (control, 21.1 ± 1.7 μM; P < 0.001). In glaucomatous vitreous humor, TRAP decreased by 42% at 15 days and 78% at 60 days (control, 414 ± 29 μM; P < 0.001). In glaucomatous aqueous humor, TRAP values were 75 ± 7 μM (7 days), 54 ±4 μM (15 days), 25 ± 4 μM (30 days), and 50 ± 3 μM (60 days) (control, 90 ±10 μM; P < 0.001). CONCLUSIONS. Reactive species were increased in glaucoma, as evidenced by the increases in CL, TBARS, and NC. The decrease in the antioxidant levels may be a consequence of an increase in oxidative processes.