Supplementing Plant-Based Docosahexaenoic Acid From Bioactive Canola, with Arachidonic Acid, in Maternal Diet Is Beneficial for Immune System of the 3 Week BALB/c Offspring

Abstract

Objectives To understand the mechanism behind the programming effect of docosahexaenoic acid (DHA, derived from genetically modified Canola) supplementation (along with arachidonic acid, AA) during breastfeeding period on immune development of 3 wk pups using BALB/c mouse. Methods Pregnant mice, 5 days prior to parturition, were randomized to consume DHA diet (1% DHA, 1% AA w/w total fat, n = 10) or control diet (0% DHA and AA, n = 12) for 3-wk post-parturition (suckling period). At birth, pups were cross fostered to ensure equal pups per dam. Dams and 3-wk old pups were euthanized and spleen was collected for analysis. Immune cells were isolated to study ex-vivo cytokine production by innate (bacterial stimulant, lipopolysaccharide; LPS) and adaptive (lymphocyte stimulant phorbol myristate acetate + ionomycin; PMAi) immune cell. Cytokine were measured by Meso Scale (electrochemiluminescent assay) and splenocyte phenotyping by flow cytometry. Data was analyzed using Student's T test. Results Food intake, bodyweight, spleen weight and splenocyte count showed no diet effect in dams or pups. DHA diet in dams resulted in lower proportion of CD86+ (effector cells, P = 0.01) and higher proportion of CD138 + plasma B cells (P < 0.001) in splenocyte than control, however, total B cells (CD45R+) and total T cells (CD3+) showed no diet effect. Although, ex-vivo cytokine production (IL-1β, IL2, IL-4, IL-5, IL-6, IL-10, IL-12, CXCL-1, TNFα and IFN-γ) by splenocytes to PMAi in dams did not differ between diet groups. In pups, splenocytes proportion of effector T cells (CD3 + CD28+) was 20% lower, whereas mature B cells (CD19 + and IgG+) was higher in DHA diet group (P's < 0.05). Additionally, dendritic cell (CD103+) was 30% higher in DHA group with no difference in other innate cells. DHA diet significantly improved inflammatory response of innate cells to LPS (TNFα, IFNγ and IL-1β) and overall response of adaptive cells to PMAi (∼ 50% higher IL-10, IL-6, and CXCL-1) compared to control 3-wk pups. Conclusions Adaptive immune cell response improved in 3-wk pups from dams supplemented with dietary DHA and AA, despite lower effector T cells, this may be due to higher antigen presentation function of mature B cells and dendritic cells. Funding Sources Alberta Canola, NSERC, and product from Nuseed; ALES AGES (awarded to Patel, D.).