Polyunsaturated fatty acids induce modification in the lipid composition and the prostaglandin production of the conjunctival epithelium cells

Abstract

This study was conducted to evaluate whether polyunsaturated fatty acids (PUFA) such as γ-linolenic acid (GLA) and eicosapentaenoic acid (EPA), as found in the diet, may affect the lipid composition of conjunctival epithelium and whether these modifications affect prostaglandin (PG) production after inflammatory stimulation. Chang and IOBA-NHC conjunctival human cells were treated with GLA and/or EPA at 5, 10, 20, 30, 40, or 50μg/ml for 72h and then were stimulated with interferon-gamma (IFN-γ) for 48h. Changes in the composition of neutral lipids and phospholipids were monitored by gas chromatography. PGE1 and PGE2 levels were measured by enzyme immunoassay. PUFA supplementations in the culture medium induced incorporation of these fatty acids and of their metabolites in neutral lipids and phospholipids of the conjunctival cells. The fatty acid composition of neutral lipids and phospholipids was not affected by stimulation with IFN-γ. The production of PGE1 and PGE2 was affected by GLA supplementation whereas it was not modified by EPA supplementation. A combined supplementation of EPA and GLA did not change the production of PGE1 but decreased the production of PGE2. These results suggest that modulation of fatty acid composition and PG production by PUFA supplementation is possible in the conjunctival epithelium, which is an important site of inflammation in dry eye syndrome.