Time Course Changes of Oxidative Stress Markers in a Rat Experimental Glaucoma Model

PURPOSE. To evaluate the relationship between oxidative stress markers and increased intraocular pressure in experimental glaucoma. METHODS. In vivo chemiluminescence (CL), total antioxidant capacity (TRAP), nitrite concentration (NC), and lipid peroxidation markers (TBARS) were evaluated. Wistar rats (n = 18 for each time point) underwent operation, and two episcleral veins were cauterized. RESULTS. Decreases of 22%, 35%, and 27% at 7, 15, and 30 days and an increase of 22% at 60 days in CL were observed in glaucomatous eyes. In optic nerve, TBARS values were 6.9 +/- 0.5 nmol/mg protein (7 days), 9.4 +/- 0.4 nmol/mg protein (15 days), 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 mu M (7 days), 31.4 +/- 1.2 mu M (15 days), 39.6 +/- 1.3 mu M (30 days), and 40.0 +/- 1.3 mu M (60 days) (control, 21.1 +/- 1.7 mu M; P < 0.001). In glaucomatous vitreous humor, TRAP decreased by 42% at 15 days and 78% at 60 days (control, 414 +/- 29 mu M; P < 0.001). In glaucomatous aqueous humor, TRAP values were 75 +/- 7 mu M (7 days), 54 +/- 4 mu M (15 days), 25 +/- 4 mu M (30 days), and 50 +/- 3 mu M (60 days) (control, 90 +/- 10 mu M; 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. (Invest Ophthalmol Vis Sci. 2010; 51: 4635-4640) DOI: 10.1167/iovs.09-5044