Dietary intervention with serum-derived bovine immunoglobulins protects barrier function in a mouse model of colitis

Abstract

Dietary supplementation with immunoglobulins from animal plasma has anti-inflammatory effects on intestinal and lung models of acute inflammation. Here, we aimed to establish whether dietary intervention with serum-derived bovine immunoglobulin (SBI) can prevent alterations in intestinal barrier function in a mouse model with a genetic predisposition to inflammatory bowel disease (IBD). Wild-type (WT) mice and mice lacking the mdr1a gene (KO) were fed diets supplemented with either SBI (2% wt/wt) or milk proteins (control diet), from day 21 (weaning) until day 56. The epithelial permeability of distal colon crypts was measured by confocal microscopy using a fluorescent marker. The expression of junctional epithelial E-cadherin and β-catenin proteins were determined by Western blot and zonula occludens-1 (ZO-1) by immunofluorescence. Mucins (MUC1, MUC2, MUC4), TFF3, cytokines (TNF-α, IFN-γ), and inducible nitric oxide synthase RNA expression were quantified by real-time PCR. SBI blocked the increase in colon crypt permeability and partially prevented the reduction in E-cadherin and ZO-1 expression that characterize the KO mouse model (both P < 0.05). SBI inclusion also reduced the mucosal expression of the inflammatory markers TNF-α, IFN-γ, and inducible nitric oxide synthase (all P < 0.005). The number of goblet cells in the colon of KO mice was low and correlated well with MUC2 and TFF3 expression (P < 0.001), whereas dietary supplementation with SBI attenuated these effects (all P < 0.05). In short, dietary SBI ameliorated colonic barrier alterations and reduced the expression of mucosal inflammatory markers in a genetic model of IBD.

The Anti-Inflammatory Effect of Spray-Dried Plasma Is Mediated by a Reduction in Mucosal Lymphocyte Activation and Infiltration in a Mouse Model of Intestinal Inflammation

“…Reduction in ICAM-1 expression would explain previous results using the mouse colitis model in which plasma protein supplementation reduced leukocyte infiltration into the colon mucosa [9,17]. Other supplements with anti-inflammatory properties, such as ginkgo leaf extracts [45], or drugs such as the β-adrenergic antagonist carvedilol [46] can also inhibit endothelial adhesion to monocytes by reducing VCAM-1 expression via suppression of NF-κB signaling pathways.…”

“…The observation that SDP supplementation increases the expression of TGF-β could explain the improvement in barrier function observed in rats challenged with SEB [24] and in mice that develop colitis [9,17]. The role of TGF-β in barrier function is partially mediated by Smad2/3 signaling pathways [47].…”

“…RNA extraction and reverse transcription were carried out as described previously [17]. RNA quality and quantity were assessed by spectrophotometry (NanoDrop ND-1000; ThermoFisher Scientific, Waltham, MA, USA).…”

“…Previous research indicated that 7 to 8 animals are enough to observe SDP effects on immune populations [19], while 4 to 5 samples are sufficient to detect changes in gene expression [17]. Mean values of normally distributed data were compared using one-way ANOVA followed by Fisher least square difference (LSD) post hoc test.…”

“…Studies of pigs challenged with pathogenic microorganisms indicate that SDP has anti-inflammatory effects because it reduces the expression of pro-inflammatory cytokines [16]. In our laboratory, we previously identified the lymphoid cell subsets as well as the cytokines and chemokines involved in GALT stimulation that are eventually modulated by plasma protein supplements [7,17]. In all instances, plasma supplements reversed the changes in the ratio of activated-to-regulatory T-lymphocytes that is characteristic of inflammatory syndromes, and promoted the expression of anti-inflammatory cytokines.…”