《Phytomedicine》（IF:8.3）|西北工业大学：蝉花多糖通过调节“肠道菌群-胆汁酸代谢-FXR”轴改善溃疡性结肠炎

溃疡性结肠炎是一种慢性、复发性炎症性肠道疾病，与肠道菌群失调和胆汁酸稳态异常密切相关。来自蝉拟青霉的多糖具有免疫调节和抗炎作用，但其在UC中的治疗潜力及机制尚不明确。近期，西北工业大学的一项研究利用DSS诱导的结肠炎小鼠模型，系统探究了蝉花多糖的治疗作用及其背后的“肠道菌群–胆汁酸代谢–免疫”调控网络。研究发现，CCP主要由葡萄糖、甘露糖和半乳糖组成，具有典型的多糖结构和均一的分子量分布。CCP治疗显著改善了DSS诱导的结肠炎，减轻了体重下降、结肠缩短和组织病理学损伤。16S rDNA测序表明，CCP恢复了肠道微生物多样性，并显著富集了梭菌属Kas107-2。靶向代谢组学显示，CCP使胆汁酸代谢正常化，表现为次级胆汁酸水平升高，初级胆汁酸水平降低。机制上，CCP激活了法尼醇X受体信号，抑制了IκBα磷酸化和NF-κB通路，下调了促炎细胞因子，并增强了紧密连接蛋白的表达。特别重要的是，粪菌移植实验证实，来自CCP处理小鼠的菌群足以在受体小鼠中复制这些保护效果。该研究首次系统阐明了蝉花多糖通过促进梭菌簇XIVa增殖、调节胆汁酸代谢、激活FXR、抑制NF-κB驱动的炎症反应，从而增强肠上皮屏障功能的完整机制。

研究背景

溃疡性结肠炎是一种慢性、特发性炎症性肠病，以反复发作和缓解为特征。组织病理学上，UC主要累及结肠黏膜和黏膜下层的弥漫性炎症，导致反复发作的腹泻、黏液脓血便、腹痛和里急后重。流行病学监测显示，全球范围内UC的发病率和患病率持续上升。UC的当代标准疗法主要包括氨基水杨酸类药物、皮质类固醇、免疫抑制剂以及靶向炎症介质的生物制剂，如抗TNF-α单克隆抗体。尽管如此，这些药物常常伴随着重大挑战：部分患者表现出原发性或获得性耐药，长期用药会增加机会性感染、骨髓抑制、代谢异常的风险以及停药后复发率高。尽管生物制剂已经改变了UC的治疗模式，但仍有高达40%-50%的患者反应不佳。此外，高昂的经济负担，年花费动辄数十万元，给医疗资源带来了相当大的压力。因此，寻找疗效确切、不良反应小、复发率低的治疗药物已成为炎症性肠病研究的首要目标和关键需求。

源自传统中草药的天然多糖因其卓越的生物相容性和低毒性，使其适用于UC这类慢性、复发性疾病的长期应用，成为有前景的候选药物。由于其植物来源、多方面的药理活性和良好的安全性，这些多糖有望成为有前景的治疗候选物。重要的是，它们解决了现有药物治疗靶点受限、副作用显著、停药后疾病复发率高等关键局限性。因此，源自传统中药的多糖为开发更安全、更有效的UC干预措施提供了一个有前景的平台。

蝉拟青霉，通常被称为蝉花，是一种著名的传统药用真菌，寄生在蝉若虫上，形成复杂的生物活性结构。在传统实践中，蝉花以疏散风热、定惊解痉、明目益视而著称，应用于小儿神经系统和眼科疾病。近年来，从体外培养的菌丝体中分离出越来越多的次级代谢产物，包括多糖、虫草酸、过氧化麦角甾醇以及一系列具有生物活性的核苷。蝉花多糖（CCP）是一种主要的生物活性成分，具有抗肿瘤、免疫调节、抗炎、抗菌和抗氧化特性。最近的研究表明，CCP可以重塑肠道微生物结构，增加产SCFA的菌群，抑制促炎菌群，并通过菌群-免疫互作来改善炎症。然而，CCP在UC中的治疗潜力的全面机制解析仍有待确定。

研究内容

本研究旨在确定CCP是否通过调节肠道菌群组成和影响FXR/NF-κB信号通路，发挥抗炎和肠道屏障保护作用。通过剖析“菌群-代谢-免疫”轴内的复杂相互作用，本研究旨在阐明CCP可能改善UC的多效性机制，从而提供令人信服的临床前证据，以支持其作为治疗UC的创新、安全、有效治疗剂的推进。

研究结果

Fig. 1. The Physicochemical Characterization of CCP. (A) FT-IR spectral analysis characterizing the chemical structure of CCP. (B) Monosaccharide composition profiling of CCP. (C) The Molecular Mass Determination of CCP. Red trace represents multi-angle laser light scattering, blue trace indicates the differential signal, and black trace displays regression-derived molecular weight values. (D) CCP molecular conformation mapping, with log(Molar Mass) plotted against log(R.M.S. Radius); the calculated slope serves as a molecular conformation index. (E-G) Scanning electron microscopy micrographs visualize the microarchitecture of CCP at increasing magnification. CCP: Cordyceps cicadae polysaccharides; FT-IR: Fourier-Transform Infrared Spectroscopic.

Fig. 2. Amelioration of UC symptoms by CCP in DSS-Induced UC mice. (A) Schematic of the experimental design. (B) Disease activity index (DAI) scores for body weight loss, stool consistency, and rectal bleeding. (C, D) Representative images and quantitative analysis of colon length. (E) Serum levels of inflammatory cytokines (TNF-α, IL-1β, IL-6). (F) Hepatic function markers (ALT, AST) and renal function indicators (urea, creatinine). (G) Representative H&E-stained colonic tissue sections. (H) Representative AB-PAS-stained colon sections. Data are mean ± SD. p < 0.05; p < 0.01; p < 0.001 vs. Model group. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid.

Fig. 3. CCP mitigates DSS-induced disruption of the intestinal barrier. (A) Immunofluorescence visualization of Claudin-1, Occludin, and ZO-1 expression (n = 3). (B) immunofluorescence visualization of co-localization ZO-1 and E-cadherin expression (n = 3). (C) Immunoblot and quantification of Claudin-1, Occludin, and ZO-1 in colonic tissue (n = 3). All results are representative of at least 3 biological replicates. Data are shown as mean ± SD; an unpaired t-test was used for statistical evaluation. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid. FXR: farnesoid X receptor.

Fig. 4. Modulation of gut microbiota by CCP in DSS-Induced colitis mice. (A) Chao1 diversity rarefaction curves across cohorts normalized to identical 16S rDNA gene sequence numbers (n = 6). (B) Shannon diversity indices derived from 16S rDNA amplicon data (n = 6). (C) Principal coordinates analysis (PCoA) based on unweighted UniFrac distances differentiates microbial community structures among control, model, I-CCP, H-CCP, and 5-ASA groups. (D) Relative abundance of the 20 most significantly altered genera. (E) LEFSe analysis with a stringent LDA threshold of >3.0 identified significant alterations at the species level among the five groups. (F) LDA histograms unequivocally indicated a marked expansion in the relative abundance of key microbial biomarkers across the experimental groups. Results are presented as mean ± SD. The unpaired t-test was used for statistical analysis. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid.

Fig. 5. Alleviation of UC through gut microbiota modulation by fecal microbiota transplantation. (A) Schematic of the experimental protocol assessing CCP-modulated microbiota effects via FMT. (B) Disease activity index (DAI) scores for body weight, rectal bleeding, and stool consistency after fecal microbiota transplantation (n = 8). (C) Gross colonic images after fecal transplantation in various treatment groups (n = 8). (D) Analysis of colon length after fecal microbiota transplantation (n = 8). (E) The serum concentrations of inflammatory cytokines (TNF-α, IL-1β, and IL-6) in different groups following fecal transplantation (n = 6). (F) Representative H&E-stained colonic tissue sections following fecal transplantation (n = 3). (G) Representative images of AB-PAS-stained mouse colon tissue from each group following fecal transplantation (n = 3). H&E and AB-PAS are representative of at least 3 biological replicates. Data are expressed as mean ± SD. Statistical analysis was performed using the unpaired t-test. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid. PGF: pseudo-germ-free.

Fig. 6. FMT-CCP mitigates DSS-induced disruption of the intestinal barrier. (A) Immunofluorescence visualization of Claudin-1, Occludin, and ZO-1 expression after fecal microbiota transplantation (n = 3). (B) immunofluorescence visualization of co-localization ZO-1 and E-cadherin expression after fecal microbiota transplantation (n = 3). (C) Immunoblot and quantification of Claudin-1, Occludin, and ZO-1 in colonic tissue after fecal microbiota transplantation (n = 3). All results are representative of at least 3 biological replicates. Data are shown as mean ± SD; an unpaired t-test was used for statistical evaluation. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid. FXR: farnesoid X receptor.

Fig. 7. FMT-CCP mitigates UC through modulating gut microbial communities. (A) Chao1 alpha diversity rarefaction after FMT in groups normalized to equal 16S rDNA sequence numbers (n = 6). (B) Post-FMT Shannon diversity indices (n = 6). (C) PCoA plots of unweighted UniFrac distances illustrating group-specific gut microbiota clustering among F-control, F-model, F-l-CCP, F-H-CCP, and F-5-ASA after fecal microbiota transplantation. (D) Relative abundance analyses of the top 20 genera with significant compositional changes following fecal transplantation. (E) LEfSe analysis with a stringent LDA threshold of > 3.0 identified significant alterations at the genus level among the five groups. (F) Heatmap showing the top 30 species with significant abundance changes following fecal transplantation across groups. (G) The relative abundance of Clostridium Kas107-2 in differents groups following fecal transplantation. Data are mean ± SD; the unpaired t-test was used. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid. FMT: fecal microbiota transplantation; PGF: pseudo-germ-free.

Fig. 8. Amelioration of serum and colon bile acid dysregulation by CCP and FMT-CCP. (A) Principal component analysis (PCA) of serum bile acid concentrations among experimental groups by CCP and FMT-CCP (n = 6). (B) Measurement of major serum bile acids levels following CCP treatment and FMT-CCP in DSS-induced mice (n = 6). (C) The significantly altered serum bile acids following CCP treatment and FMT-CCP in DSS-induced mice (n = 6). (D) Total, primary, and secondary serum bile acid quantification (n = 6). (E) Determination of total, free, and conjugated serum bile acids (n = 6). (F) Principal component analysis (PCA) of colon bile acid concentrations among experimental groups by CCP and FMT-CCP (n = 6). (G) Measurement of major colon bile acids levels following CCP treatment and FMT-CCP in DSS-induced mice (n = 6). (H) The significantly altered colon bile acids following CCP treatment and FMT-CCP in DSS-induced mice (n = 6). (I) Total, primary, and secondary colon bile acid quantification (n = 6). (J) Determination of total, free, and conjugated colon bile acids (n = 6). Data are shown as mean ± SD. Statistical comparisons were made using the unpaired t-test. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid; FMT: fecal microbiota transplantation; DCA: deoxycholic acid; LCA: lithocholic acid; 12-keto LCA: 12-keto lithocholic acid; α-MCA: α-muricolic acid; β-MCA: β-muricolic acid.

Fig. 9. Amelioration of fecal bile acid dysregulation by CCP and FMT-CCP. (A) Principal component analysis (PCA) of fecal bile acid concentrations among experimental groups by CCP and FMT-CCP (n = 6). (B) Measurement of major fecal bile acids levels following CCP treatment and FMT-CCP in DSS-induced mice (n = 6). (C) The significantly altered fecal bile acids following CCP treatment and FMT-CCP in DSS-induced mice (n = 6). (D) Total, primary, and secondary fecal bile acid quantification (n = 6). (E) Determination of total, free, and conjugated fecal bile acids (n = 6). (F) Spearman correlation heatmap between the relative abundance of Clostridium Kas107-2 and key bile acids. Data are shown as mean ± SD. Statistical comparisons were made using the unpaired t-test. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid; FMT: fecal microbiota transplantation; DCA: deoxycholic acid; LCA: lithocholic acid; 12-keto LCA: 12-keto lithocholic acid; α-MCA: α-muricolic acid; β-MCA: β-muricolic acid.

Fig. 10. CCP Modulates the FXR/NF-κB Axis. (A) Immunoblot and quantification of FXR and FGF15 levels in colon tissue by CCP and FMT-CCP (n = 3). (B) ChIP assay for IgG and FXR, and subsequent qPCR in NF-κB promoter, IgG as a negative control; Luciferase activity of NF-κB promoter in HCT116 and HT29 cells after GW4064 (24 μM) treatment, firefly luciferase activity was normalized to Renilla luciferase activity (transfection control). (C) Immunoblot analysis of proteins involved in the NF-κB pathway, including NF-κB, phosphorylated NF-κB, IκBα, and phosphorylated IκBα, in colonic tissue by CCP and FMT-CCP (n = 3). (D) Immunoblot and quantification of pro-inflammatory mediators IL-1β, IL-6, and TNF-α in colon tissue by CCP and FMT-CCP (n = 3). All results are representative of at least 3 biological replicates. Data are shown as mean ± SD; an unpaired t-test was used for statistical evaluation. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; 5-ASA: 5-Aminosalicylic Acid; FMT: fecal microbiota transplantation; FXR: farnesoid X receptor.

Fig. 11. The essential role of FXR in attenuation of UC manifestations by CCP. (A) Overview of the experimental workflow evaluating the essential role of FXR attenuation of UC manifestations by CCP using a DSS-induced colitis mouse model (B) Disease activity index (DAI) scores measuring weight loss, hematochezia and fecal consistency in experimental cohorts (n = 8). (C) Macroscopic visualization of colonic morphology across groups (n = 8). (D) Analysis of colon length in different groups (n = 8). (E) The serum concentrations of inflammatory cytokines (TNF-α, IL-1β, and IL-6) in different groups (n = 6). (F) Representative images of hematoxylin and eosin (H&E)-stained colon tissue (n = 3). (G) Representative images of AB-PAS-stained mouse colon tissue from each group (n = 3). H&E and AB-PAS are representative of at least 3 biological replicates. Results are presented as mean ± SD. Statistical significance was determined using an unpaired t-test. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; Z: Z-gugglusterone; DCA: deoxycholic acid.

Fig. 12. The essential role of FXR by CCP in Modulating the related protein expressions of the FXR/NF-κB Axis. (A) Immunoblot and quantification of FXR and FGF15 levels in colon tissue (n = 3). (B) Immunoblot analysis of proteins involved in the NF-κB pathway, including NF-κB, phosphorylated NF-κB, IκBα, and phosphorylated IκBα, in colon tissue (n = 3). (C) Immunoblot and quantification of pro-inflammatory mediators IL-1β, IL-6, and TNF-α in colon tissue (n = 3). All results are representative of at least 3 biological replicates. Results are presented as mean ± SD. Statistical significance was determined using an unpaired t-test. p < 0.05; p < 0.01; p < 0.001. UC: ulcerative colitis; CCP: Cordyceps cicadae polysaccharides; Z: Z-guguglusterone; DCA: deoxycholic acid.

Fig. 13. Schematic illustration of the proposed mechanisms by which CCP alleviates ulcerative colitis.

研究结论

总之，本研究阐明，蝉花多糖对肠道微生物组进行全面调节，促进梭菌簇XIVa驱动的次级胆汁酸合成，诱导FXR通路激活，抑制NF-κB依赖性炎症反应，增强紧密连接蛋白表达，并恢复黏膜屏障功能。通过在微生物群-胆汁酸-免疫信号三联体中阐明这些相互关联的机制，本研究为CCP作为功能性食品或UC及相关炎症性肠病的辅助疗法的进一步开发提供了坚实的科学基础。

搜寻路径

英文名称：Cordyceps cicadae polysaccharides ameliorate ulcerative colitis by modulating the gut microbiota and regulating the bile acid/FXR/NF-κB signaling pathway

DOI：https://doi.org/10.1016/j.phymed.2026.158007