Administration of xylo-oligosaccharides improves depressive-like behaviour in mice caused by chronic unpredictable mild stress by altering microbiota composition

Xylo-oligosaccharides (XOS) is a functional oligosaccharide with prebiotic properties, and could be fermented by gut microbiota. In this study, the modulatory effects of XOS on emotions and behaviours at different dose were investigated based on the mouse model of chronic unpredictable mild stress-induced depression. The result showed that 0.23 and 0.50 g kg⁻¹ doses of XOS significantly increased sucrose preference index and decreased the immobility time in tail suspension and forced swimming tests. Meanwhile, the dose of 0.23 g kg⁻¹ day⁻¹ XOS significantly increased the concentration of neurotransmitters, such as 5-hydroxytryptamine and γ- aminobutyric acid. Furthermore, the analysis of the faecal microbiota with XOS intervention showed a higher relative abundance of Akkermansia, Bifidobacterium and Lactobacillus, fewer Desulfovibrio and the SCFA concentrations increased with XOS prevention treatment. These results suggested that the dietary supplementation XOS could improve chronic stress-induced depressive-like behaviour by modulating neurotransmitters and reverting gut microbiota changes in mice. These findings present XOS as a potential prebiotic targeting to the gut microbiota for mood disorders.     

枸杞粉及其多糖对环磷酰胺致免疫低下小鼠免疫及肠道菌群的调节作用

枸杞是我国传统的药食两用资源,其鲜果喷雾干燥粉作为食品或功能食品原料被广泛应用,但其功效作用研究较少。本研究以环磷酰胺（cyclophosphamide,CTX）诱导免疫低下的小鼠为模型,探究枸杞粉（Lycium barbarum L. powder,LB）、枸杞多糖（Lycium barbarum L. polysaccharides,LBP）及复配物（LB＋LBP）对小鼠免疫力及肠道菌群稳态的影响。结果表明,LB、LBP及LB＋LBP均可不同程度地恢复免疫抑制小鼠的体质量和采食量,改善小鼠的脾脏、胸腺和结肠组织损伤,有效促进免疫抑制小鼠肿瘤坏死因子（tumor necrosis factor-α,TNF-α）、白细胞介素（interleukin,IL）-1β、干扰素-γ（interferon-γ,IFN-γ）和免疫球蛋白A（immunoglobulin A,IgA）的分泌,调节结肠中免疫相关基因的表达,促进短链脂肪酸（short-chain fatty acids,SCFAs）生成,显著调节Muribaculaceae_unclassified、Muribaculum、Mucispirillum、Helicobacter、Bilophila、Clostridiales等相对丰度（P＜0.05）,逆转CTX诱导的小鼠肠道菌群代谢功能异常,并使其趋于正常。相较于LBP,LB、LB＋LBP还可降低Clostridiales相对丰度,增加有益菌Duncaniella的相对丰度,LB＋LBP还可降低厌氧菌Anaerotruncus的相对丰度。本研究结果将为枸杞精深加工产业中功效针对性健康产品研发和多元化产品开发提供理论依据。