Alistipes indistinctus 菌益生元筛选及其合生元效果验证

Screening of Prebiotics for Alistipes indistinctus and Verification of Synbiotic Effects

摘要:

为了筛选促进Alistipes indistinctus（A. indistinctus）生长的益生元，评价其改善肠屏障功能的合生元效应，本研究选取菊粉、抗性淀粉、麦芽糊精、β-葡聚糖、低聚果糖、低聚异麦芽糖及低聚木糖作为候选物质，采用体外发酵体系筛选益生元，并确定低聚木糖为最优益生元，再利用液相色谱质谱（HPLC-MS）分析不同聚合度低聚木糖（XOS）的代谢特征；在小鼠模型中，通过灌胃A. indistinctus+XOS评估其肠道定植能力及对结肠屏障蛋白（ZO-1、Occludin、MUC-2）表达的影响，结合荧光原位杂交（FISH）观察菌体在肠黏膜的附着情况；在脂多糖（LPS）诱导的Caco-2细胞模型中检测该组合对菌体黏附性及屏障修复作用。结果显示，XOS在所有益生元中对A. indistinctus的促生长及代谢活性提升最显著，多种聚合度均可有效利用；在小鼠中，A. indistinctus+XOS组肠道定植时间较单用A. indistinctus组延长，结肠ZO-1和MUC-2蛋白分别升高约43.26%和21.12%，肠黏膜附着菌量提高约118.75%；在Caco-2模型中，该组合显著减轻LPS诱导的屏障通透性增加，并恢复屏障蛋白至对照组的约70.83%。综上，XOS是促进A. indistinctus生长与肠道定植的优选益生元，A. indistinctus+XOS组合在增强肠屏障功能方面具有显著合生元潜力，为相关功能食品及微生态制剂的研发提供理论依据与实验基础。

Abstract:

To screen prebiotics that promote the growth of Alistipes indistinctus (A. indistinctus) and evaluate their synbiotic effects on improving gut barrier function, this study employed an in vitro fermentation system to investigate a range of candidate prebiotics, including Inulin, Resistant Starch, Maltodextrin, β-glucan, Fructooligosaccharides (FOS), Isomaltooligosaccharides (IMO), and Xylooligosaccharides (XOS). Low-degree polymerized XOS was identified as the optimal prebiotic based on its growth-promoting effects. Subsequently, liquid chromatography-mass spectrometry (HPLC-MS) was applied to analyze the metabolic characteristics of XOS with different degrees of polymerization. In a mouse model, the gut colonization ability of A. indistinctus and its effects on the expression of colon barrier proteins (ZO-1, Occludin, MUC-2) were evaluated through oral gavage of A. indistinctus+XOS, and fluorescence in situ hybridization (FISH) was used to observe the attachment of the bacteria to the intestinal mucosa. In LPS-induced Caco-2 cell models, the effects of this combination on bacterial adhesion and barrier repair were examined. The results indicated that XOS was the most effective prebiotic for enhancing the growth and metabolic activity of A. indistinctus among all tested prebiotics, with various degrees of polymerization being efficiently utilized. In the mouse model, the A. indistinctus+XOS group exhibited prolonged gut colonization time compared to the A. indistinctus-only group, with a 43.26% and 21.12% increase in ZO-1 and MUC-2 protein expression, respectively, and an 118.75% increase in bacterial adhesion to the intestinal mucosa. In the Caco-2 model, this combination significantly reduced LPS-induced increases in barrier permeability and restored barrier protein levels to approximately 70.83% of the control group. In conclusion, XOS is an optimal prebiotic for promoting the growth and gut colonization of A. indistinctus. The A. indistinctus+XOS combination shows significant synbiotic potential in enhancing gut barrier function, providing a theoretical basis and experimental foundation for the development of functional foods and microbiological formulations.