Abstract
Abstract: :
Purpose: Oxidative stress and antioxidants systems may be associated with glaucomatous damage. The aim of the present study was to establish the antioxidant status of the aqueous humor in Exfoliation Syndrome Glaucoma patients in comparison with a control group. For this purpose we studied the activities of antioxidant defense enzymes superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) and the total reactive antioxidant potential (TRAP) in aqueous humor. Methods: Aqueous humor was obtained at the time of glaucoma surgery from 18 patients with Exfoliaton Syndrome Glaucoma (XFSG), 24 patients with primary open angle glaucoma (POAG) and 24 control patients. The activity of the antioxidant enzymes was measured spectrophotometrically. SOD was determined by measuring the inhibition in the rate of adrenochrome formation at 480 nm. Catalase was evaluated by measuring the decrease in absorbance at 240 nm. GPx was determined following NADPH oxidation at 340 nm. TRAP was measured by chemiluminiscence. Results: An increase in SOD activity was observed in XFSG patients group (44.2 ± 6.7 U SOD / mL) when compared with control patients (26.5 ± 0.6 U SOD / mL p< 0.0001). GPx activity was 3 fold higher in XFSG patients than in the control group (6.1 ± 0.6 U / mL p<0.0001). No significant changes were found in catalase levels of glaucoma patients. TRAP values of XFSG group was 66 ± 13 µM Trolox. This value was significantly decreased, by 35 %, in XFSG patients than in control group (124 ± 5 µM p< 0.0001). The antioxidant status of the aqueous humor in Exfoliation Syndrome Glaucoma patients was not significantly different when compared with the POAG group. Conclusion: SOD and GPX were increased and Total Antioxidant Capacity was decreased in the aqueous humor of Exfoliation Syndrome Glaucoma. TRAP, GPX and SOD activities may be useful oxidative stress markers in the aqueous humor of XFSG patients. Oxidative stress may lead to the induction of antioxidant enzymes and contribute to the observed TRAP decrease.
Keywords: 504 oxidation/oxidative or free radical damage • 324 aqueous • 356 clinical (human) or epidemiologic studies: systems/equipment/techniques