thromboxane-b2 and Retinitis

The role of metabolites of arachidonic acid (AA) in experimental autoimmune uveoretinitis was studied using inhibitors of AA metabolism. Nordihydroguaiaretic acid (NDGA), which inhibits predominantly the lipoxygenase (LO) pathway, or indomethacin, a specific cyclo-oxygenase (CO) inhibitor, was administered to rats immunized with retinal S antigen. Levels of various AA metabolites were measured in the inflamed uvea, and the severity of intraocular inflammation was quantitated by morphometric analysis. Histopathologically, the uveoretinitis was significantly suppressed following treatment with NDGA, while indomethacin treatment resulted in augmentation of the disease (p less than 0.05). These results tend to indicate that the inhibition of the LO rather than the CO pathway may be more beneficial in the treatment of autoimmune uveitis.

Topics: Animals; Anthropometry; Anti-Inflammatory Agents, Non-Steroidal; Antigens; Arrestin; Dinoprostone; Disease Models, Animal; Eye Proteins; Female; Indomethacin; Leukotriene B4; Masoprocol; Radioimmunoassay; Rats; Rats, Inbred Lew; Retinitis; Thromboxane B2; Uveitis, Posterior

The anti-inflammatory effects of vitamin E were investigated using the S antigen model of uveoretinitis. Thirty-six 3-week-old Lewis rats were separated into three groups and maintained on a specially formulated diet. One group of animals received a diet deficient in vitamin E; a second group received a normal diet containing vitamin E, and the third group, in addition to receiving the normal diet, received vitamin E supplementation. At 9 weeks of age, all rats were sensitized to S antigen. Six animals in each group were killed on day 14 and the remaining animals on day 21 following immunization. Both histopathologic and biochemical studies were conducted to evaluate the tissue damage observed in animals maintained on different dietary levels of the vitamin. The intraocular inflammation in the vitamin E-supplemented group was considerably smaller than in the other two groups (p less than 0.01). The former group had the highest level of vitamin E in both the eye and plasma (mean value 1.13 micrograms/mg protein and 23.9 micrograms/ml, respectively), while the vitamin E-deficient group had the lowest levels (mean values of 0.16 micrograms/mg protein and 0.48 micrograms/ml in the eye and plasma, respectively). Results of the radioimmunoassay for the determination of the arachidonic acid metabolites revealed significantly lower levels of thromboxane B2 in the vitamin E-supplemented group (2.04 +/- 0.45 pg/mg) than in the normal (4.33 +/- 0.98 pg/mg) or the vitamin E-deficient (5.21 +/- 1.12 pg/mg) groups (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antigens; Arrestin; Autoantigens; Choroid; Diet; Dinoprostone; Disease Models, Animal; Eye Proteins; Female; Leukotriene B4; Membrane Proteins; Phosphodiesterase Inhibitors; Radioimmunoassay; Rats; Rats, Inbred Lew; Retinitis; Thromboxane B2; Uveitis; Vitamin E