Role of Catalase in Retinal Antioxidant Defence System: Its Comparative Study among Rabbits, Guinea Pigs, and Rats

Abstract

The role of catalase in the retinal antioxidant defence system was examined in rabbits, guinea pigs, and rats with and without prolonged administration of a diet containing 0.4% 3-aminotriazole (3-AT), a catalase inhibitor. When weanling rabbits, guinea pigs, and rats were administered 3-AT for 8,7, and 10 weeks, respectively, retinal catalase activity was reduced by approximately 50% in all these animals. In the retina of rabbits with 3-AT administration, a decrease in superoxide dis-mutase (SOD) activity and an increase in lipid peroxide (LPO) concentration occurred, while glutathione peroxidase (GSH-px) activity did not change. In the retina of guinea pigs with 3-AT administration, an increase in LPO concentration occurred, while SOD and GSH-px activities did not change. In the retina of rats with 3-AT administration, a decrease in GSH-px activity and an increase in LPO concentration occurred, while SOD activity did not change. An increase in serum LPO concentration was found in rats with 3-AT administration, while the concentration did not change in rabbits and guinea pigs. These results indicate that catalase plays an important role in the retinal antioxidant defence system, but that the way catalase contributes to the maintenance of the retinal antioxidant defence system is different among these animals. The present results suggest that under the prolonged inhibition of catalase, the retina of rats, but not of rabbits and guinea pigs, may suffer from the influence of systemic oxidative stress.