Weitao Geng

Inflammatory bowel disease (IBD) is a chronic intestinal disorder closely linked to gut microbiota dysbiosis and metabolic disturbances. This study investigated the alleviating effects and mechanisms of Bifidobacterium animalis subsp. lactis C-2 (C-2) on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. The results demonstrated that C-2 significantly ameliorated pathological phenotypes in DSS-induced UC mice, including reduced weight loss, lowered disease activity index (DAI) scores, restored colon length, and diminished inflammatory damage of colonic tissue. Meanwhile, C-2 effectively repaired the intestinal barrier by enhancing the expression of tight junction proteins (Claudin-1, Occludin, ZO-1) and MUC2, thereby reducing lipopolysaccharide in serum and rebalancing pro-inflammatory (TNF-α, IL-6, IL-1β) and anti-inflammatory (IL-10) cytokines in the colon and serum. Notably, C-2 reshaped the gut microbiota structure, significantly increasing microbial diversity (Shannon index) and enriching beneficial bacteria such as Bifidobacterium and Prevotellaceae. Metabolomic analysis further revealed that C-2 modulated the gut tryptophan metabolism pathway, influencing the levels of tryptophan-derived indole metabolites including indole-3-propionic acid (IPA) and indole-3-acrylic acid (I3A), which were associated with activation of the aryl hydrocarbon receptor (AhR)/Cyp1a1 signaling pathway to enhance barrier integrity and suppress inflammation. Moreover, C-2 intervention restored short-chain fatty acids (SCFAs) levels. In summary, C-2 alleviates UC in mice through synergistic mechanisms including optimizing gut microbiota composition, boosting SCFA production, and enhancing tryptophan-derived metabolites. Collectively, these findings support the potential of C-2 as a candidate probiotic intervention strategy for IBD.

Previous studies have shown that supplementation with specific probiotics can be used to alleviate allergy symptoms. The purpose of this study was to evaluate the anti-allergic effects of Lactobacillus kefiranofaciens ZW3 (ZW3) in ovalbumin (OVA)-induced allergic mice. The mice were divided into six groups: the food allergy group, positive group (Lactobacillus rhamnosus GG), low-dose ZW3 group, middle-dose ZW3 group, high-dose ZW3 group, and the control group involving healthy mice. BALB/c mice were intraperitoneally injected with OVA/complete Freund’s adjuvant (CFA) for allergy sensitization. Probiotics were administered orally once every two days in the probiotic-treated groups. The allergic score, serum OVA-sIgE, body mass, thymus, and spleen indexes were detected on day 22, and the relative mRNA expression of inflammatory cytokines was detected via RT-qPCR. The results suggest that the body weight and thymus index returned to normal levels; allergy scores, serum OVA-sIgE, IL-4, IL-5, and IL-10 expression decreased; and IFN-γ and IL-2 increased significantly in the ZW3 group compared with the allergy group. Furthermore, ZW3 decreased Muribaculaceae and Ruminococcaceae abundance and increased Lachnospiraceae abundance in the intestinal flora. In summary, ZW3 induced anti-allergic effects by increasing Th1 cytokines and decreasing Th2 cytokines, which can remarkably ameliorate the symptoms of an ovalbumin-induced food allergy.

Introduction: Several studies indicated that depression is associated with liver injury. The role of probiotics in alleviating depression is focused on improving the abnormalities of the central nervous system through the gut-brain axis, while the effect on liver injury is still unclear. The aim of this study was to elucidate the potential link between the antidepressant effect of a potential probiotic strain Bifidobacterium pseudocatenulatum W112 and its effect on alleviating liver injury.Methods: The 4-week-old Kunming mice were exposed to chronic stress for 4 weeks to establish a depression model.Results: The depression-like behavior and related biomakers in chronic unpredictable mild stress (CUMS) mice were altered by supplemented with W112 for 2 weeks. Meanwhile, the modulation effect of W112 the gut microbiota in CUMS mice also result in an increase in the abundance of beneficial bacteria and a decrease in the abundance of harmful bacteria. Significantly, liver injury was observed in CUMS model mice. W112 improved liver injury by reducing AST/ALT in serum. Quantitative PCR results indicated that the mechanism of action of W112 in ameliorating liver injury was that the altered gut microbiota affected hepatic phospholipid metabolism and bile acid metabolism.Discussion: In short, W112 could significantly improve the depressive and liver injury symptoms caused by CUMS. The gut-liver-brain axis is a potential connecting pathway between the antidepressant effects of W112 and its alleviation of liver injury.

Lactiplantibacillus plantarum D-9 shows neuroprotective effects on anxiety- and depression-like disorders in CUMS mice by modulating tryptophan metabolism and the gut microbiota.

The combined intervention of Lactobacillus kefiranofaciens ZW18 and anti-PD-1 was able to improve the anti-melanoma therapeutic efficacy of PD-1 inhibitors by modulating the gut microbiota and activating tumor immunity.

In this study, Lactiplantibacillus plantarum BC299, Lactobacillus delbrueckii subsp. bulgaricus 717 and Streptococcus thermophilus 176 were used as combined starter cultures to produce a fermented soy whey beverage. The results showed that the fermentation of the combined starter cultures increased the content of lactic acid, acetic acid, succinic acid, and malic acid, while decreased the content of citric acid, fumaric acid and propionic acid. Meanwhile, the fermentation also effectively changed the proportion of volatile flavor substances. The higher sensory score of the fermented soy whey also confirmed the flavor improvement effect of the combined starter cultures. In addition, the in vivo results of animal experiments showed that the fermented soy whey could significantly improve the disease activity index (DAI) and colon morphology in dextran sulfate sodium (DSS) induced colitis mice. This study showed that the combined lactic acid bacteria starter cultures had important value-added relevance on the effective reuse of the soy whey by-product.

Kombucha, which is rich in tea polyphenols and organic acid, is a kind of acidic tea soup beverage fermented by acetic acid bacteria, yeasts, lactic acid bacteria. Kombucha has been reported to possess anti-diabetic activity, but the underlying mechanism was not well understood. In this study, a high-fat, high-sugar diet combined with streptozotocin (STZ) injection was used to induce T2DM model in mice. After four weeks of kombucha intervention, the physiological and biochemical index were measured to determine the diabetes-related indicators. High-throughput sequencing technology was used to analyze the changes in gut microbiota from the feces. The results showed that four weeks of kombucha intervention increased the abundance of SCFAs-producing bacteria and reduced the abundance of gram-negative bacteria and pathogenic bacteria. The improvement in gut microbiota reduced the damage of intestinal barrier, thereby reducing the displacement of lipopolysaccharide (LPS) and inhibiting the occurrence of inflammation and insulin resistance in vivo. In addition, the increased levels of SCFAs-producing bacteria, and thus increasing the SCFAs, improved islet β cell function by promoting the secretion of gastrointestinal hormones (GLP-1/PYY). This study methodically uncovered the hypoglycemic mechanism of kombucha through gut microbiota intervention, and the result suggested that kombucha may be introduced as a new functional drink for T2DM prevention and treatment.

Non-alcoholic fatty liver disease (NAFLD) has become a highly concerned health issue in modern society. Due to the attentions of probiotics in the prevention of NAFLD, it is necessary to further clarify their roles. In this study, the methionine and choline-deficient (MCD) diet induced NAFLD rats model were constructed and treated with strain L. plantarum MA2 by intragastric administration once a day at a dose of 1 × 10⁸ cfu/g.bw. After 56 days of the therapeutic intervention, the lipid metabolism and the liver pathological damage of the NAFLD rats were significantly improved. The content of total cholesterol (TC) and total triglyceride (TG) in serum were significantly lower than that in the NAFLD group (p < 0.05). Meanwhile, the intestinal mucosal barrier and the structure of intestinal microbiota were also improved. The villi length and the expression of claudin-1 was significantly higher than that in the NAFLD group (p < 0.05). Then, by detecting the content of LPS in the serum and the LPS-TLR4 pathway in the liver, we can conclude that Lactobacillus plantarum MA2 could reduce the LPS by regulating the gut microecology, thereby inhibit the activation of LPS-TLR4 and it downstream inflammatory signaling pathways. Therefore, our studies on rats showed that L. plantarum MA2 has the potential application in the alleviation of NAFLD. Moreover, based on the application of the strain in food industry, this study is of great significance to the development of new therapeutic strategy for NAFLD.