PROSTAGLANDIN-E2 AND F2-ALPHA IN THE LEWI S RAT UVEITIC GLAUCOMA MODEL

Purpose In the preinflammatory phase of S-antigen (S-ag) induced uveit is, an ocular hypotension occurs between day 2 and day 6 after S-ag in jection. To better understand this phenomenon, we studied the levels o f prostaglandin E2 (PGE2) and prostaglandin F2-alpha (PGF2-alpha) in t he aqueous humor of S-ag injected rats at various time points after in duction of disease. Methods Twenty-five female Lewis rats weighting 15 0 to 175 gm were injected in the hind foot-pad with 50 mu g of S-antig en. IOP was measured each day at 9 am with a Tone-Pen tonometer. Aqueo us humor was collected at days 0, 2, 4, 6, 9, 14 and 18 after S-ag inj ection. PGE2 and PGF2-alpha were assayed in the aqueous humor using an enzyme immunoassay method. Results The concentration of PGE2 increase d after day 6 and peaked at day 14 after S-ag injection (45,6+/-9,0 mu /ml vs 1,1+/-0,1 mu/ml in controls, P = 0,04). The peak of PGE2 corres ponded to the maximum inflammation and ocular hypertension. PGF2-alpha was increased from day 2 to day 6, with a peak at day 6 after S-ag in jection (128,0+/-51 pg/ml vs 56+/-2,0 pg/ml in controls, P = 0,047), w hich corresponded to the preinflammatory ocular hypotension. A second peak was observed at day 18 after S-ag injection (3643+/-824 pg/ml, P = 0,049), which corresponded to the cessation of intraocular inflammat ion and ocular hypertension. Conclusions The early increased concentra tion of PGF2-alpha in the aqueous humor of rats with S-ag induced uvei tis may explain the ocular hypotension observed from day 2 to day 6 af ter S-ag injection.