Effects of different antioxidants on lens-induced uveitis

For evaluation of the effects of different free-radical scavengers on biochemical changes in lens-induced uveitis (LIU), ten male Wistar rats were sensitized for 8 weeks using bovine lens protein and Freund's adjuvant. The uveitis was induced by disruption of the lens capsule. One group of animals received superoxide dismutase and catalase (SOD/CAT); a second group of animals was treated with vitamin E. Lipid peroxides (LPO) of the retinal tissue and aqueous humor served as parameter of oxidative tissue damage. Glutathione (GSH/GSSG) of the aqueous humor was evaluated as a parameter of the tissue's redox state. For evaluation of the inflammatory response, myeloperoxidase activity (MPO) was determined in the iris/ciliary-body complex. SOD/CAT produced no improvement in the significantly (P < 0.05) elevated MPO and LPO values recorded for untreated control animals. Following vitamin E treatment the GSH/GSSG and LPO values in aqueous humor were markedly improved as compared with controls. Retinal LPO values were significantly (P < 0.05) reduced as compared with controls. No change in MPO levels was observed. The results demonstrate that enzymes such as SOD and CAT do not influence tissue damage at a significant level, whereas radical chain breakers such as vitamin E can do so. However, the inflammatory response itself is not reduced. To achieve global results, drugs are necessary that act on both free radicals produced by noninflammatory pathways and those originating from inflammation.