STUDIES ON INTRAOCULAR INFLAMMATION PRODUCED BY INTRAVITREAL HUMAN INTERLEUKINS IN RABBITS

Recombinant human interleukin-1α, interleukin-1β (10, 80 or 200 units), interleukin-8 (10 or 40 units) or endotoxin was injected intravitreally into rabbit eyes. Twenty-four hours thereafter aqueous humor protein, leukocyte number, prostaglandin E2, leukotriene B4 and rabbit interleukin-1β were measured. In addition, synthesis of prostaglandin E2 and leukotriene B4 in iris-ciliary body and myeloperoxidase (MPO) activity were determined. Recombinant human interleukins 1α and 1β, but not interleukin-8 induced signs of uveitis, i.e. protein and leukocytic infiltration into aqueous humor. At 200 unit activities, human interleukin-1β was significantly greater than interleukin-1α in causing leukocyte infiltration response. Interleukin-1α did not stimulate the release of prostaglandin E2 or leukotriene B4. In fact, interleukin-1β significantly inhibited the synthesis of prostaglandin E2 in iris-ciliary body. Both of these human interleukins caused a release of rabbit interleukin-1β in aqueous achieving a level significantly higher than observed after endotoxin injection. This study demonstrates that intravitreal injections of human IL-1α and IL-1β induce uveitis by releasing rabbit interleukin-1β within the eye. © 1993 Academic Press, Inc.