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Early weaning usually causes intestinal disorders, enteritis, and diarrhea in young animals and human infants. Astragalus polysaccharides (APS) possesses anti‐inflammatory activity. To study the anti‐inflammatory mechanisms of APS and its potential effects on intestinal health, we performed an RNA sequencing (RNA‐seq) study in lipopolysaccharide (LPS)‐stimulated porcine intestinal epithelial cells (IPEC‐J2) in vitro. In addition, LPS‐stimulated BALB/c mice were used to study the effects of APS on intestinal inflammation in vivo. The results from the RNA‐seq analysis show that there were 107, 756, and 5 differentially expressed genes in the control versus LPS, LPS versus LPS+APS, and control versus LPS+APS comparison groups, respectively. The results of Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that the mitogen‐activated protein kinase (MAPK) and nuclear factor‐κB (NF‐κB) signaling pathways play significant roles in the regulation of inflammatory factors and chemokine expression by APS. Further verification of the above two pathways by using western blot and immunofluorescence analysis revealed that the gene expression levels of the phosphorylated p38 MAPK, ERK1/2, and NF‐κB p65 were inhibited by APS, while the expression of IκB‐α protein was significantly increased (p <.05), indicating that APS inhibits the production of inflammatory factors and chemokines by the inhibition of activation of the MAPK and NF‐κB inflammatory pathways induced by LPS stimulation. Animal experiments further demonstrated that prefeeding APS in BALB/c mice can alleviate the expression of the jejunal inflammatory factors interleukin 6 (IL‐6), IL‐Iβ, and tumor necrosis factor‐α induced by LPS stimulation and improve jejunal villus morphology. [ABSTRACT FROM AUTHOR]

The endotoxin of Gram-negative bacteria threatens the intestinal health of livestock. Ethyl pyruvate (EP) has been shown to regulate intestinal immunity and protect against cell and tissue damage. In this study, it was first verified that EP could reduce the secretion of IL-8, TNF-α, IL-6 and IL-1β in LPS-induced IPEC-J2 cells. Then, we used RNA sequencing (RNA-seq) to analyze the differentially expressed genes (DEGs) of inflammatory factors induced by LPS in IPEC-J2 cells. It was found that LPS induced the upregulation of 377 genes and the downregulation of 477 genes compared to Vehicle; LPS+EP induced the upregulation of 258 genes and the downregulation of 240 genes compared to Vehicle; and LPS+EP induced the upregulation of 373 genes and the downregulation of 188 genes compared to LPS (fold change > 1.5 and FDR < 0.01). Their enrichment pathways included the MAPK signaling pathway, PI3K-Akt signaling pathway, Toll-like receptor signaling pathway, and other pathways. Furthermore, the mRNA level of cytokines associated with inflammation and apoptosis enriched in the MAPK pathway was verified by qRT-PCR. Western blots and immunofluorescence revealed that EP significantly inhibited phosphorylated p38 and phosphorylated-ERK1/2 protein expression levels (P < 0.05). The apoptosis due to LPS reduced by EP was significantly inhibited, as shown by Annexin V-FITC/PI staining. According to the results, EP inhibited the expression of IL-8, TNF-α, IL-6 and IL-1β as well as apoptosis by inhibiting the phosphorylation of p38 and ERK1/2 in LPS-induced IPEC-J2 cells. [ABSTRACT FROM AUTHOR]

Salmonella typhimurium is one of the main causes of intestinal diseases, affecting the health of humans and livestock. Ethyl pyruvate (EP), which is ordinarily an edible spice, has been indicated to exert anti-inflammatory effects and preserve intestinal barrier function. In this study, intestinal immune function and signaling pathways activated by EP were investigated in vivo in S. typhimurium- challenged BALB/c mice and in vitro in RAW264.7 cells. EP improved body weight loss and the organ index of the liver and spleen (p < 0.05). Serum IgA and IgM levels were significantly increased in EP-treated mice (p < 0.05). According to histopathological and immunohistochemical staining, EP significantly increased the villus height, reduced edema in the jejunum and increased the levels of claudin-1, occludin-1 and ZO-1 proteins compared to the Salmonella -treated group (p < 0.05). In addition, EP decreased the levels of the IL-6, IL-1β and TNF-α mRNA levels in jejunum, liver, spleen and RAW264.7 cells (p < 0.05). EP decreased the levels of TLR4, phosphorylated p38MAPK and ERK1/2 in mice infected with S. typhimurium (p < 0.05). In conclusion, EP effectively protected BALB/c mice from an intestinal S. typhimurium infection by improving the activity of the humoral immune system, reducing intestinal barrier damage, and inhibiting proinflammatory cytokine production in the jejunum by modulating the TLR4/MAPK signaling pathway. Based on these findings, EP has the potential to inhibit inflammation or to serve as an immune-enhancing adjuvant. [ABSTRACT FROM AUTHOR]