Early-life feeding of arachidonic acid and docosahexaenoic acid beneficially modulated ileum and splenocyte oxylipins to support oral tolerance development in allergy-prone BALB/c mice

Abstract

Background: Early-life feeding of arachidonic acid (ARA)+docosahexaenoic acid (DHA) has been shown to promote immune changes associated with oral tolerance (OT). Oxylipins have been demonstrated to be modulated by diet and alter immune function.

Objective: To determine whether early-life feeding of ARA+DHA modulated the ileum and ovalbumin (OVA)-challenged splenocyte oxylipin profile in a way that is beneficial for OT development.

Method: Allergy-prone BALB/c dams were fed a control (0 %ARA, 0 %DHA) or ARA+DHA (1 %ARA, 1 %DHA) diet during suckling. At 3wks, half of the pups were killed to analyze ileum morphology and oxylipin profile. The remaining pups continued consuming the maternal diets. From day 21-25, pups received daily oral gavage of sucrose or OVA, followed by intraperitoneal OVA injections on day 35 and 41. At 6wks, pups were killed to analyze plasma OVA-specific-IgE and -IgG, ileum morphology, splenocyte phospholipid fatty acid composition and ex vivo splenocyte oxylipin production after OVA stimulation.

Results: ARA+DHA supplementation resulted in a 5-fold reduction in plasma OVA-IgE concentration, confirming OT development. At 3wks, ARA+DHA-fed mice had higher ileum levels of 8-HETE, 14,15-DiHETrE, 4-HDHA, 17-HDHA and 19,20-EpDPE and lower levels of 13-HODE and 20-HETE, which suggests better ileum maturation, lower inflammation and enhanced tolerogenic immune regulation to support OT. The longer villi, shorter crypts and higher villus/crypt ratio confirmed the superior ileum maturation. At 6wks, ARA+DHA supplementation increased oxylipin substrates (ARA, DHA, linoleic acid and eicosapentaenoic acid) in splenocyte phospholipids. After OVA stimulation, splenocytes from ARA+DHA-fed mice produced more PGD2, 5-HETE, 15-HETE and 20-HDHA and less TXB2 and 12-HETE, which suggests inhibited Th2 and allergic responses and enhanced tolerogenic immune modulation to support OT.

Conclusion: Early-life feeding of ARA+DHA beneficially modulated the oxylipin profile in the ileum and OVA-challenged splenocytes to support OT development.

Keywords: Eicosanoids; Food allergy; Immune system; Long-chain polyunsaturated fatty acids; Ovalbumin; Th2 response.