Effects of systemically applied allopurinol and prednisolone on experimental autoimmune uveitis

Purpose: To compare the effects of allopurinol to those of prednisolone on the oxidative tissue damage and inflammatory response in experimental autoi mmune uveitis (EAU). Methods: Experiments were performed using 27 male Lewis rats. EAU was induc ed by means of crude retina extract, Found's adjuvant and pertussis toxin. One group of animals served as controls and two groups were treated systemi cally, one with allopurinol and one with prednisolone. At the end of the ex periments lipid peroxides (LPO), myeloperoxidase activity (MPO), and histol ogical changes were determined in the retinal tissue. LPO were measured by two different methods [thiobarbituric acid reactive substances (TBARS) and malondialdehyde-like substances]. Results: Allopurinol led to a significant reduction in LPO and MPO levels. The steroid treatment also resulted in a significant reduction in MPO activ ity but LPO were significantly reduced only when measured as TEARS. Histolo gical changes were significantly reduced by allopurinol only. Discussion: Allopurinol is more effective than prednisolone in treating EAU . Its efficacy can be explained by the antioxidative/antiinflammatory and p robably immunological action. The antiinflammatory effects of prednisolone are not sufficient to reduce the tissue damage. Allopurinol promises to be a useful alternative to steroids in the treatment of uveitis.