Dietary Plasma Protein Supplements Prevent the Release of Mucosal Proinflammatory Mediators in Intestinal Inflammation in Rats

Abstract

Spray-dried plasma (SDP) is a complex mixture of active proteins that modulates the immune response of gut-associated lymphoid tissue. We examined whether SDP and Ig concentrate (IC) supplementation could modulate cytokine expression and inflammatory mediators in rats challenged with Staphylococcus aureus enterotoxin B (SEB). Wistar-Lewis rats were fed diets supplemented with SDP (8% wt:wt), IC (1.5% wt:wt), or milk proteins (control diet) from weaning (d 21) to d 34 after birth. On d 32 and 35, the rats were given SEB (0.5 mg/kg; intraperitoneal). Six hours after the second SEB dose, jejunal mucosa and Peyer’s patches (PP) from the small intestine were collected. The cytokines interferon-γ (IFNγ), tumor necrosis factor-α (TNFα), interleukin (IL)-6, IL-10, transforming growth factor-β (TGFβ), and leukotrienne B4 (LTB4) were analyzed using commercial kits. SEB increased the release of proinflammatory mediators (IFNγ, TNFα, IL-6, and LTB4) in PP (P < 0.05) and in the mucosa (P < 0.05). In both tissues, SDP prevented the increase in IFNγ, IL-6, and LTB4 induced by SEB (P < 0.05). IC reduced the expression of TNFα and LTB4 in PP and mucosa (P < 0.05). SDP supplementation increased IL-10 and mature TGFβ concentrations in intestinal mucosa from both inflamed and noninflamed rats. Both SDP and IC increased the mature:total TGFβ ratio (all P < 0.05). Both supplements were effective at preventing the SEB-induced increase in proinflammatory:antiinflammatory cytokine ratios in PP and mucosa and in serum. The preventive effects of plasma supplements on intestinal inflammation involve modulation of intestinal cytokines, characterized by an increased expression of antiinflammatory cytokines.