Abstract
Abstract: :
Purpose: To evaluate the total antioxidant capacity of aqueous humor of cats in relation to plasma and aqueous humor ascorbic acid levels. Methods: Plasma and aqueous humor were obtained at around 8 am from fasted adult normal cats (n=22). Total antioxidant capacity of aqueous humor was considered to be the capacity to inhibit free radical generation by an aqueous solution of 2,2–azobis (2–amidopropane) chlorine – ABAP. An aqueous solution of ABAP produces peroxyl radicals that are scavenged by antioxidants of aqueous humor. Chemiluminescence emitted by peroxyl radials was mesaured with a scintillation counter. The amount of antioxidants in aqueous humor depends on the time for light emission recovery, reported as minute. Ascorbic acid of both plasma and aqueous humor were measured by HPLC with UV detection. Results: Ascorbic acid levels of plasma and aqueous humor of normal cats were 2,4 ± 1,3 µM and 55,9 ± 31,7 µM respectively (Mean ± SD). Total antioxidant capacity of aqueous humor expressed in minutes was 13,05 ± 5,06 (Mean ± SD). There was a high significant correlation (r=0.5408; P=0.0094) between total antioxidant capacity and ascorbic acid levels in the aqueous humor. No correlation exists between plasma and aqueous humor ascorbic acid levels. Conclusions: The levels of ascorbic acid in aqueous humor and plasma were determined in normal cats by HPLC technique. The concentrations found well correlates with the previous described in the literature. The correlation between ascorbic acid levels and total antioxidant capacity of aqueous humor suggests that ascorbic acid is an important component of the antioxidant activity of aqueous humor. Plasma levels of ascorbic acid are not predictive of aqueous humor ascorbic acid levels.
Keywords: antioxidants • aqueous • oxidation/oxidative or free radical damage