Indomethacin and the epinephrine-induced breakdown of the blood-ocular barrier in rabbits

Using aqueous and vitreous fluorophotometry, the authors examined the blood-aqueous and blood-retinal barrier functions in three groups of pigmented rabbits. Epinephrine (1.25%) was applied topically five times daily and indomethacin (0.5% sesame oil suspension) was applied topically three times daily to one eye of each of the animals in Group 1; under the same regimen, epinephrine and indomethacin placebo were administered to one eye of each of the animals in Group 2 and epinephrine placebo and indomethacin placebo were administered to one eye of each of the animals in Group 3. Fluorophotometry was done 1, 2, and 3 months after drug administration. The results showed that epinephrine induced disruption of the blood-aqueous barrier 2 and 3 months after drug administration, and that the magnitude of this disruption increased with time. Epinephrine also induced disruption of the blood-retinal barrier 3 months after drug administration. Indomethacin significantly prevented disruption of the blood-aqueous barrier at 2 and 3 months and significantly prevented disruption of the blood-retinal barrier at 3 months. The magnitudes of the barrier disruptions in eyes treated with both epinephrine and indomethacin were slightly higher than, or the same as, those of the control eyes. The results strongly indicated that the epinephrine-induced disruption of the blood-ocular barrier was partially caused by prostaglandins and other cyclo-oxygenase products whose biosynthesis was initiated by epinephrine.