Effet chez le porcelet d'une exposition à un régime co-contaminé en ...

TRAVAIL EXPERIMENTAL3) Intestinal immune responseTo evaluate the mechanisms of porcine intestinal defense against multi-mycotoxin exposure, wequantified the expression of genes coding for pro-inflammatory cytokines after chronic ingestion ofmycotoxin co-contaminated feed. Statistically significant changes in gene expression in differentregions relative to control and treated animals are shown in Figures 7 and 8.In general, the jejunum showed greater induction of cytokines as more cytokines were expressedin this region after mycotoxin exposition. DON treated group demonstrated significant increase inmRNA encoding for IL-1β, IL-6, MIP-1β, IL-2, and IL-12p40 in the jejunum, whereas FB induced asignificant increase in IL-10 and IFN-γ. In the ileum, all treatments induced significant increases inTNF-α and IL-1β.4) Expression of adherens junction proteinsThe expression of E-cadherin and occludin, two junction proteins involved in the adherence andpermeability of enterocytes, was analyzed in the ileum of animals by western blotting (WB). Afternormalization by the housekeeping gene β-actin, the data revealed a significant decrease ofexpression of both proteins compared to the control animals. In animals exposed to the cocontaminateddiet, the defective expression of E-cadherin and occludin was more pronounced(Figure 9).As WB indicated a significant decrease in the total amount of E-cadherin expression in the ileum,we decided to evaluate the expression of this protein in enterocytes, using an immunohistochemicalassay. The expression of E-cadherin in the jejunum and ileum was significantly reduced in the groupsthat received mono-contaminated or co-contaminated diets (Figure 9). The reduction was mostpronounced in the ileum of the DON+FB group, in which all animals showed weak and irregularstaining.116