Inhibition of COX in Ocular Tissues: An In Vitro Model to Identify Selective COX-2 Inhibitors

The aim of this work was to study the regulation of LPS-stimulated PGE ₂ synthesis by traditional NSAIDs (piroxicam and diclofenac) and a selective COX-2 inhibitor (NS-398), in cultured bovine corneal endothelial cells and retinal pigmentary epithelial cells. The IC₅₀ values of piroxicam and diclofenac were compared with IC₅₀ values of NS-398; diclofenac, in both types of cells, showed higher potency than piroxicam. Diclofenac seemed to be a COX-2 inhibitor because its IC₅₀ values were similar to the IC₅₀ values of NS-398. We suggest that this in vitro cell assay system could be useful for identifying compounds that selectively inhibit COX-2 in ocular tissues.