Steroidal and nonsteroidal drugs in endotoxin-induced uveitis

Various classes of anti-inflammatory compounds like steroids (dexamethasone), cyclooxygenase inhibitors (indomethacin and flurbiprofen), 5-lipoxygenase inhibitors (BWA 218C and BWA 4C), immunosuppressive drugs (cyclosporin and rapamycin) and cod liver oil were tested for their antiinflammatory activities in endotoxin-induced uveitis model in rabbits. Intraocular inflammation was assessed in terms of two inflammatory responses i.e. breakdown of blood-aqueous barrier (BAB) and leukocyte infiltration into aqueous humor and iris ciliary body (ICB). Prostaglandin (PG) E2 and leukotriene (LT) B4 release into aqueous humor was also measured. Indomethacin significantly inhibited PGE2 release without affecting leukocyte or BAB response. Flurbiprofen prevented leukocyte, PGE2 and LTB4 release into aqueous humor but not ICB chemotaxis. BWA 218C and BWA 4C also significantly inhibited leukocyte and LTB4 release but not BAB responses. Dexamethasone (2mg/kg, i.m.) and cyclosporin A (25 mg/kg i.m.) significantly inhibited leukocyte infiltration into aqueous humor and ICB, and PGE2 release but they failed to inhibit breakdown of BAB and LTB4 release. On the other hand, rapamycin (10mg/kg i.m.) and cod liver oil (1 ml daily i.m. up to 15 days) significantly prevented leukocyte and BAB response. Cod liver oil also significantly inhibited PGE2 and LTB4 release but rapamycin affected only PGE2 release into aqueous humor. It is concluded that arachidonic acid metabolites may not play a vital role in this uveitis model and additional proinflammatory mediators like cytokines may be involved.