[Ameliorative effect of refined polysaccharides from bran-fried Atractylodis Rhizoma on cyclophosphamide-induced immunosuppression and intestinal injury in mice by regulating linoleic acid metabolism].

By using a mouse model with cyclophosphamide-induced immunosuppression and intestinal injury, this study evaluated the therapeutic advantages of refined polysaccharides from bran-fried Atractylodis Rhizoma in alleviating intestinal injury in immunosuppressed mice and explored its underlying mechanisms. Fifty male C57BL/6 mice were randomly divided into five groups: a normal group, a model group, a group of crude polysaccharides from bran-fried Atractylodis Rhizoma(1 200 mg·kg~(-1)), a group of refined polysaccharides from bran-fried Atractylodis Rhizoma(842 mg·kg~(-1)), and a positive control group(40 mg·kg~(-1) levamisole hydrochloride), with 10 mice in each group. The normal group was administered saline via gavage, while the other groups received their respective treatments for 15 consecutive days. Except for the normal group, all other groups were intraperitoneally injected with cyclophosphamide(80 mg·kg~(-1)) on days 8-10 to establish the immunosuppression and intestinal injury model. Body weight was monitored throughout the experiment. After the experiment, the spleen and thymus indices of mice were measured. Hematoxylin-eosin(HE) staining was used to evaluate pathological changes in the spleen, thymus, and small intestine tissue. Quantitative real-time polymerase chain reaction(qRT-PCR) was employed to detect the expression level of tumor necrosis factor-α(TNF-α), interleukin-6(IL-6), and interleukin-1β(IL-1β) mRNAs in the small intestine tissue. Alcian blue-periodic acid-Schiff(AB-PAS) staining and immunohistochemistry staining were used to assess the number of goblet cells and the expression of mucoprotein 2(MUC2) in the small intestine tissue. Immunofluorescence was performed to detect the expression of zonula occludens-1(ZO-1), occludin, and immunoglobulin A(IgA)-secreting cells in the small intestine tissue. Enzyme-linked immunosorbent assay(ELISA) was used to measure the content of secretory IgA(sIgA) in the small intestine tissue, and untargeted metabolomics was applied to analyze changes in metabolites in the small intestine tissue. The results showed that compared with those in the model group, the body weight, thymus index, spleen index, number of goblet cells, and the expression level of MUC2, TNF-α, IL-6, IL-1β, ZO-1, occludin, IgA-secreting cells, and sIgA were significantly increased in the groups of crude polysaccharides and refined polysaccharides from bran-fried Atractylodis Rhizoma. Refined polysaccharides from bran-fried Atractylodis Rhizoma demonstrated significantly stronger regulatory effects on the thymus index, ZO-1, occludin, and IL-6 compared to crude polysaccharides. Metabolomics analysis identified 13 differential metabolites in the model group and the groups of crude polysaccharides and refined polysaccharides from bran-fried Atractylodis Rhizoma, This involved 15 metabolic pathways, including unsaturated fatty acid biosynthesis, dicarboxylic acid metabolism, and linoleic acid metabolism. Among these, linoleic acid metabolism was identified as the primary metabolic pathway regulated by polysaccharides from bran-fried Atractylodis Rhizoma. Compared to crude polysaccharides, refined polysaccharides from bran-fried Atractylodis Rhizoma exhibited superior regulatory effects on metabolites in the small intestine tissue. In conclusion, the study demonstrates that both crude polysaccharides and refined polysaccharides from bran-fried Atractylodis Rhizoma can ameliorate cyclophosphamide-induced immunosuppression and intestinal injury, with refined polysaccharides showing superior efficacy. Its mechanism of action is closely related to the linoleic acid metabolism pathway.