Effects of sodium naproxen eye drops on rabbit ocular inflammation induced by sodium arachidonate

Sodium naproxen, a reversible competitive inhibitor of cyclooxygenase, is widely used as an anti-inflammatory agent in clinical practice. The purpose of this study was to determine whether eye drops containing 0.5% (w/v) sodium naproxen reduce a number of inflammatory responses produced by sodium arachidonate in the rabbit's eye. Sodium naproxen eye drops successfully reduced the primary signs of ocular inflammation elicited by 0.5% sodium arachidonate on conjunctiva and iris. However, the drug was less effective in reducing conjunctival inflammation induced by 1% sodium arachidonate. Sodium naproxen treatment significantly reduced the levels of prostaglandin E2 (PGE2), polymorphonuclear leukocytes and protein concentration in aqueous humor samples obtained from the eyes of rabbits treated with 0.5% sodium arachidonate whereas aqueous humor levels of leukotriene B4(LTB4) were not found significantly different from control rabbits. Interestingly, PGE2 as well as LTB 4 "de novo" production by corneas and lenses obtained from rabbits sacrificed 2 h after arachidonate and incubation "in vitro" for 20 min were significantly higher in samples taken from controls than in tissues obtained from the eyes treated with sodium naproxen eye drops. Finally, this drug treatment significantly antagonized the rise in intraocular pressure induced by 0.5% sodium arachidonate. Present data suggest that sodium naproxen may be employed topically to prevent ocular inflammatory reactions where the arachidonic acid cascade is activated.