The Occurrence Mechanism Of Piglet Colitis Induced By Dextran Sodium Sulfate Based On Intestinal Microbiome And Host Immune

Piglets are not well developed and are susceptible to various stress factors,causing diarrhea and intestinal inflammation,resulting in decreased growth performance and increased mortality of piglets,bringing serious economic losses to the pig industry.Clarifying the mechanism of intestinal inflammation in piglets is important for the drug treatment and nutritional regulation of intestinal inflammation.Therefore,this study used a model of piglet colitis induced by dextran sodium sulfate(DSS),and analyzed the gene expression and intestinal microbial composition changes of piglet colons by transcriptomics and microbiome,providing a new target for exploring the regulation of intestinal inflammation in piglets.Eighteen healthy piglets(Duroc × Landrace × Yorkshire)weaned at 21 days of age were randomly divided into three groups after 7 days of prefeeding:(1)Control group(CON);(2)Dextran sodium sulfate group(DSS),3%(w/v)DSS;(3)Anti-inflammatory positive group(MES),3%(w/v)DSS + 2 g/d mesalamine(MES)enteric-coated tablets.The experiment lasted for 14 days.From day 1 to day 13,DSS group and MES group were intragastric administration with 12 m L 3%(w/v)DSS,and control group was intragastric administration with constant volume of normal saline.MES group was added 2 g/d mesalamine enteric-coated tablet in the diet from day 1 to day 13.Serum,jejunum,colon and colonic digesta were collected after slaughter on day 14.The results showed that compared with the CON group,the gastric DSS resulted in a decrease in the average daily gain(ADG),an increase in the diarrhea index,and a damaged intestinal barrier in the piglets,which were manifested by the increased content of serum diamine oxidase(DAO)and Dlactic acid(D-lac)in the DSS group,a decrease in the height of jejunal villi,a decrease in the ratio of villi height to the depth of the crypt,and a loss of the colon,ulcers(p < 0.05);anti-inflammatory drug treatment can significantly improve the inhibition of growth performance by DSS and alleviate intestinal damage caused by DSS.Gastric DSS caused increased serum myelopoxidase(MPO),Interleukin 1β(Interleukin 1β,IL-1β),IL-12p70 levels in piglets,and anti-inflammatory treatments reduced DSS-induced elevated MPO,IL-1β,and IL-12p70 levels(p < 0.05).Gastric DSS resulted in elevated m RNA expression levels of IFN-γ,IL-17 A,IL-6 and IL-22 in the colon of piglets,accompanied by a large number of CD11 b macrophages and CD3 T cell infiltrates(p < 0.05),and antiinflammatory treatment inhibited colonic immune cell infiltration and inflammatory response caused by DSS.The results of colon Illumina transcriptome sequencing showed that compared with the CON group,there were 361 significantly differentially expressed genes in the DSS group,of which 85 gene expressions were upregulated and 276 gene expressions were down-regulated(|log2FC| ≥ 1,p-adjust ≤ 0.05);compared with the DSS group,there were 978 significantly differentially expressed genes,including 753 upregulated genes and 225 expressed downregulated genes(|log2FC| ≥ 1,p-adjust ≤ 0.05.Gene ontology(GO)functional annotations indicate that these differentially expressed genes are primarily involved in cellular metabolism and immune responses.Analysis of pathway enrichment in the Kyoto encyclopedia of genes and genomes(KEGG)showed that compared with the CON group,the gastric DSS activated the IL-17 signaling pathway,and the differentially expressed genes in this pathway were FOSB,FOS and MUC5 AC.The MES group suppressed the cytokine-cytokine receptor interaction signaling pathway and the IL-17 signaling pathway.Real-time fluorescence quantitative polymerase chain reaction(RT-q PCR)to verify differentially expressed genes enriched in cytokine-cytokine receptor interaction signaling pathways include IL-1α,IL-1β,CXCL11,CXCL9,FOSB,TNFSF8 and CCL21,RT-q PCR results were consistent with transcriptome results.The results of 16 S r RNA sequencing showed that compared with the CON group,the gastric DSS significantly increased the α diversity index chao1(p < 0.05),the ace had an increasing trend(0.05 < p < 0.1),and the MES group had no effect on the α diversity index.From the β diversity index test,there was no difference between the DSS group and the CON group(p > 0.05),but the MES group had a significant difference compared with the DSS group(p < 0.001.Principal coordinate analysis(PCo A)shows the structural separation of the intestinal flora between the DSS and CON groups(R2 = 0.268,p = 0.005).Key microbial taxa were identified by a combination of Linear discriminant analysis(LDA)and Effect size measurement(LEf Se).Gaging DSS significantly increased the relative abundance of Akkermansia at the phytophthalogenes,phytogenes and Oscillospiraceae,methanecholas and genera at the family level(p < 0.05),and the relative abundance of Spirochaetota at the phylum phylocosa(0.05 < p < 0.1).Compared with the DSS group,the MES group reduced the relative abundance of Phylum Megacella and Spirochaetota,Methanebacterium and Osillocspiraceae at the family level,and the relative abundance of B.methane in the genus level(p < 0.05).In summary,DSS-induced piglet colitis leads to intestinal damage,elevated intestinal permeability and immune cell recruitment in piglets,while anti-inflammatory drugs inhibit these DSS-induced body damage;the pathogenesis of DSS-induced piglet colitis may be related to the activation of the IL-17 signaling pathway,the infiltration of CD11 b macrophages and CD3 T cells.Anti-inflammatory treatment to alleviate DSS-induced piglet colitis may be associated with inhibition of cytokine-cytokine receptor interaction signaling pathways and IL-17 signaling pathways;DSS-induced changes in colon microbial composition during treatment with piglet colitis and anti-inflammatory drugs,in which Methanobacterium breve may play a key role in the occurrence and treatment of DSS-induced piglet enteritis.