目的 联合16S rDNA技术和代谢组学技术评价短双歧杆菌组合（BBC）抗抑郁的活性及作用机制。方法 选取36只大鼠随机分为4组：对照组、模型组、BBC（短双歧杆菌BBr60∶两歧双歧杆菌BBi32∶长双歧杆菌BL21∶嗜热链球菌ST36＝1∶1∶1∶1，1.5×10⁹ CFU· d^-1）组和氟哌噻吨美利曲辛片（阳性药，1.0 mg·kg^-1）组，除对照组外建立慢性不可预知温和应激（CUMS）抑郁大鼠模型，模型成功后ig给药4周，进行糖水偏好实验、强迫游泳实验和旷场实验评价大鼠抑郁行为，酶联免疫吸附（ELISA）法测定血清5-羟色胺（5-HT）、多巴胺（DA）和去甲肾上腺素（NE）的水平，苏木素-伊红（HE）染色观察海马CA1和CA3区的神经元细胞数目和形态变化；应用16S rDNA扩增子测序和非靶向代谢组学技术探讨BBC对抑郁大鼠肠道菌群及代谢产物的调控作用，结合Spearman系数法构建差异菌群、代谢产物的关联性。结果 与模型组比较，BBC可有效改善大鼠抑郁样行为（P＜0.05、0.01），提高血清中5-HT、DA和NE的水平，增加神经元细胞数目；有效改善抑郁大鼠的菌群失调，尤其对Bacilli纲、Lactobacillales目、Lactobacillaceae科和Lactobacillus属等菌群有回调作用（P＜0.05、0.01）；采用粪便代谢组学鉴定出与抗抑郁作用有关的主要生物标志物为1-羟-2-萘甲酸、甘草黄酮A、N-乙酰组胺等，采用血清代谢组学鉴定出与抗抑郁有关的主要生物标志物为二十二碳五烯酸、顺式-11-二十碳烯酸、3'-O-甲基巴塔氨酸III等；同时发现Lactobacillus和clostridia_UCG-014与差异代谢物存在显著关联；主要富集的通路是不饱和脂肪酸的生物合成、色氨酸代谢、丁酸代谢和烟酸和烟酰胺代谢等代谢途径。结论 BBC可通过干预相关肠道菌群和调节相关通路缓解慢性压力导致的抑郁相关症状。

Objective This study aimed to investigate the antidepressant mechanisms of combination of Bifidobacterium brevis, based on 16S rDNA technology and metabolomics technology. Methods Select 36 rats at random and divide them into four groups: control group, model group, BBC group (Bifidobacterium bifidum BBr60∶Bifidobacterium bifidum BBi32∶Lactobacillus reuteri BL21∶Streptococcus thermophilus ST36 = 1∶1∶1∶1, 1.5×10^-9 CFU · d^-1) and Fluoxetine and Mirtazapine Tablets (positive drug, 1.0 mg·kg^-1), except the control group, to establish a CUMS depression rat model with chronic unpredictable mild stress. After the model was successfully established, the rats were ig administered BBC or Fluoxetine and Mirtazapine Tablets for four weeks. The rat depressive behaviors were evaluated by the sucrose preference test, forced swimming test, and open field test, and the levels of 5-hydroxytryptamine (5-HT), dopamine (DA), and norepinephrine (NE) in the serum were determined by enzyme-linked immunosorbent assay (ELISA). The number and morphological changes of neurons in the hippocampal CA1 and CA3 regions were observed by hematoxylin-eosin (HE) staining. The effects of BBC on the gut microbiota and metabolites of depressed rats were explored by 16S rDNA amplicon sequencing and non-targeted metabolomics, and the correlation between differential gut microbiota and metabolites was established by Spearman's coefficient. Results Compared with the model group, BBC effectively ameliorated depressive-like behaviors (P <0.05 and 0.01), enhanced the levels of 5-HT and DA in the serum and increased the number of neurons in rats. It also restored gut microbiota dysbiosis, particularly by modulating taxa such as Bacilli class, Lactobacillales order, Lactobacillaceae family, and Lactobacillus genus (P <0.05、 0.01). The key biomarkers associated with the antidepressant effect identified through fecal metabolomics included 1-hydroxy-2-naphthoic acid, glycyrrhizin A, and N-acetylhistamine, while serum metabolomics revealed key biomarkers such as docosapentaenoic acid, cis-11-eicosenoic acid, and 3'-O-methylbatanin III. Significant associations were found between Lactobacillus and Clostridia_UCG-014 and differential metabolites. The enriched pathways included unsaturated fatty acid biosynthesis, tryptophan metabolism, butanoate metabolism, and nicotinate and nicotinamide metabolism, among others. Conclusion BBC alleviates depression-related symptoms induced by chronic stress by modulating gut microbiota and regulating associated metabolic pathways.

2022年湖北省自然科学基金面上类项目（2022CFB849）;2022年湖北省教育厅科学研究项目（Q20222014）