THE ROLE OF PLATELET-ACTIVATING-FACTOR IN CELL INFILTRATION IN ENDOTOXIN-INDUCED UVEITIS IN GUINEA-PIGS

Purpose. We investigated the role of platelet-activating factor (PAF) in cell infiltration in endotoxin-induced uveitis (EIU) in guinea pigs . Methods. To elicit EIU, lipopolysaccharide (LPS) was injected into t he anterior chamber of the eye. Cell numbers in the aqueous humor afte r LPS injection were determined by flow cytometry. PAF and prostagland in E-2 (PGE(2)) production after LPS injection were also examined. Res ults. Intracameral injection of LPS induced cell infiltration into the anterior chamber, and platelet-activating factor (PAF) was detected i n the aqueous humor. In addition, topical apafant (PAF antagonist) par tially inhibited cell infiltration. Intracameral injection of PAF scar cely induced cell infiltration but the reaction with EIU was accelerat ed by intracameral injection of a small amount of PAF. Conclusions. Th ese results suggest that PAF has weak direct activity on cell infiltra tion in intraocular inflammation but enhances intraocular inflammation .