Regulation Effect Of Wheat Bran Arabinoxylan On Gut Microbiota And Its Relationship With Immunomodulation

Arabinoxylan is the most abundant hemicellulose polysaccharide in wheat bran and is the main component of the cell wall.In this paper,the immunomodulatory activity of arabinoxylan was systematically studied,which provided basic data for the development and utilization of arabinoxylan as a natural immune stimulant.In addition in vitro fermentation experiment was conducted to study the regulation effect of AX on gut microbiota,futhermore the in vivo experiment was also conducted to understand whether the effect of AX on gut microbiota was related to immune regulation.This paper mainly consists of the following three parts:(1)RAW264.7 cells were treated with different concentrations of AX,and the result should that AX significantly increased the concentrations of NO,TNF-?,IL-6 and MCP-1 in a dose-dependent manner.RNA-Seq technology was used to investigate the immune stimulation molecular mechanism of AX,GO function enrichment and KEGG pathway enrichment were analyzed,we found that the main differentially expressed genes enrichment in the immune system.Moreover sixteen differentially expressed genes were selected and verified by RT-q PCR.Western blot and immunofluorescence assay proved that AX could promote the NF-?B p65 nuclear translocation,increase the phospholations of PI3K/Akt/GSK-3? signal pathway,and the NF-?B inhibitors(PDTC)significantly reduced the concentration of NO.These results indicated that AX could regulate RAW264.7 cells through NF-?B signaling pathway.(2)In vitro fermentation was used to study the effect of AX on the structure of gut microbiota,after fermentation for 48 h,the pH value of the fermentation liquor was decreased significantly,and the concentration of total sugar and reducing sugar concentration were significantly reduced,and thus generation of free monosaccharide,which illustrated that AX could be broken down and using by gut microbiota,and then the concentration of short chain fatty acids in the fermented liquid was detected.he total concentration of short chain fatty acids in fermentation liquid of AX group was 19.91±0.11mmol/L,which was significantly higher than the blank control group(13.97±0.31 mmol/L),especially in the concentration of acetic acid and propionic acid were significantly increased.Illumina platform was used for 16 S r DNA sequencing analysis of gut microbiota in fermentation broth.After fermentation for 48 h,compared with the blank control group,the abundance of Bifidobacterium,Megamonas,Preprevella?9 in AX group increased significantly,while the abundance of pathogenic bacteria such as Escherichia-Shigella was decreased.(3)It was found that AX could promote the expression of immune-associated gene m RNA in mouse peritoneal macrophages induced by AX,which may be regulated by MAPK and Akt signaling pathways.Immunosuppressant mice model were given normal saline,levamisole(40 mg/kg),low dose AX(100mg/kg)and high dose AX(300 mg/kg)for 10 days.Compared with model group,spleen index and thymus index of mice in AX group were significantly increased,and the atrophy of immune organs caused by cyclophosphamide was improved.Compared with model group,AX significantly increased the abundance of Colidextribacter and no rank f Oscillo Spiraceae,while the abundance of Turicibacter and Lactobacillus significantly decreased.