The Exorbital Lacrimal Gland Is 100 Times More Susceptible Than the Retina to Dietary Supplies in Long Chain Omega-6 and Omega 3 Polyunsaturated Fatty Acids

Abstract

Purpose:: The purpose of this study was to compare the susceptibility of the retina and the exorbital lacrimal gland to dietary supplies in long chain omega-3 (ω3) and omega-6 (ω6) polyunsaturated fatty acids (LC-PUFAs).

Methods:: Male Wistar rats were fed for 3 months with a 5% lipid-diet containing either: 1) 10% of EicosaPentaenoic Acid (EPA, ω3) and 7% of DocosaHexaenoic Acid (DHA, ω3), 2) 10% of γ-Linolenic Acid (GLA, ω6), 3) 10% of EPA, 7% of DHA and 10% of GLA or 4) a balanced diet deprived from EPA, DHA and GLA. After three months of feeding, lipids were extracted from the retina and the exorbital lacrimal gland and fatty acid composition was determined by gas chromatography.

Results:: Dietary supplementation with EPA and DHA increased ω3 PUFA levels in both the retina and the exorbital lachrymal gland. By contrast, GLA supplementation favoured ω6 PUFAs in both tissues and particularly the end-chain w6 product, DPA (DocosaPentaenoic Acid, ω6). The supplementation with EPA, DHA and GLA increased the levels of DHA (docosahexaenoic acid, ω3), EPA and dGLA (dihomo-GLA, ω6) whereas arachidonic acid (AA, ω6) was unchanged and DPA decreased in both tissues. The ratio of w6 to w3 LC-PUFAs was strongly correlated to the value observed in the diet in both tissues, but the exorbital lacrimal gland was estimated to be 100 times more susceptible than the retina to dietary supplies in w6 to w3 LC-PUFAs.

Conclusions:: Dietary PUFAs differently affect the fatty acid composition of the retina and the lacrimal gland. The lacrimal gland appears to be more sensitive to dietary changes than the retina and a concomitant use of ω3 and ω6 PUFAs may be interesting in the modulation of pro- and anti-inflammatory PUFAs, especially in the lacrimal gland.

Keywords: lacrimal gland • lipids