[Effect of melatonin instillations on the clinical course of experimental uveitis and biochemical processes in tears and aqueous humor].

Acute immunogenic uveitis was modeled in rabbits via the subcutaneous and intravitreal injections of normal horse serum. We studied the effect of instillations of 0.1% melatonin solution on the clinical course of uveitis and biochemical parameters of tear fluid and aqueous humor: antioxi-dant activity, protein concentration and α(2)-macroglobulin level. Melatonin instillations decreased clinical manifestations of uveitis. We found that the antioxidant activity in tears of the rabbits treated with melatonin was substantially higher and the α(2)-macroglobulin level lower than in untreated animals. Antioxidant activity in aqueous humor taken on day 10 of uveitis was also twice higher while protein and α(2)-macroglobulin levels were 1.5-2 times lower than in untreated animals. These data indicate that instillations of melatonin increase the local antioxidant activity and decrease the acuity of inflammation and permeability of hematoophthalmic barrier in uveitis.

[Effects of dexamethasone and superoxide dismutase instillations on clinical course of uveitis and local biochemical processes (experimental study)].

AIM: to evaluate and compare the effect of topical superoxide dismutase (SOD), which is an antioxidant enzyme, dexamethasone, and a combination of these on the course of experimental uveitis in rabbits as well as biochemical parameters of aqueous and vitreous humor. MATERIAL AND METHODS: Acute uveitis was induced in 16 rabbits by a double injection (subcutaneous and intravitreal) of normal horse serum. Of them 12 animals, divided into 3 groups of 4 each, received topical SOD, dexamethasone, or both daily for 7 days. The remaining 4 rabbits (8 eyes) were treated with placebo and, thus, constituted the control group. On day 8 the following parameters were measured in aqueous humor: protein concentration, antioxidant activity, SOD activity, α2-macroglobulin level, and leukocyte number. Total protein and albumin levels in vitreous humor were also determined. RESULTS: The effects of SOD and dexamethasone instillations were considered similar in many parameters. However, SOD was associated with a greater increase in antioxidant activity and a greater decrease in aqueous humor leukocytes, while dexamethasone was more effective in decreasing aqueous humor α2-macroglobulin and vitreous humor protein and albumin. The substances had a synergistic effect on iridal edema as well as aqueous humor leukocyte number and α2-macroglobulin level. CONCLUSION. Adding SOD to the complex therapy of uveitis results in lower inflammation intensity and enhanced dexamethasone effect.