摘要
Background:Immunosuppression compromises the host’s ability to combat pathogens,thereby increasing susceptibility to multisystem disorders.However,safe and effective curative treatments for this condition are currently lacking.Modulating the gut microbiota and their metabolites represents a promising therapeutic strategy.Notably,the Chinese herbal compound Yunzhi Guben Gao(YZG)has demonstrated multi-target immunomodulatory potential.Methods:A mouse model of dexamethasone-induced immunosuppression was employed to evaluate the effects of YZG.Immune organ indices(thymus,spleen),serum cytokine levels(IL-2,TNF-α),mucosal immunity markers(pulmonary/colonic SIgA),gut microbiota structure,and short-chain fatty acids(SCFAs)abundance were evaluated.Key microbial genera and metabolites were identified via Spearman correlation analysis.Pseudo-germ-free model mice established via quadruple antibiotic treatment combined with isovaleric acid intervention were employed to evaluate whether YZG efficacy depends on the intestinal microbiota and its metabolites,and whether its intrinsic mechanisms involve the promotion of isovaleric acid production.Results:YZG intervention ameliorated systemic and mucosal immune function in immunosuppressed mice.Mechanistically,YZG remodeled gut microbiota structure and significantly increased SCFAs levels.Notably,the abundance of the genus Ligilactobacillus exhibited the strongest positive correlation with isovaleric acid levels.Ligilactobacillus abundance was also positively correlated with immune-enhancing parameters and negatively correlated with the proinflammatory cytokine TNF-α,suggesting that Ligilactobacillus plays a pivotal role in the YZG regulatory network.Experiments using pseudo-germ-free mice and isovaleric acid intervention further demonstrated that the immunoprotective effects of YZG are closely related to intestinal microbiota remodeling and increased isovaleric acid production.Conclusion:YZG alleviates immunosuppression through multiple mechanisms,primarily involving the enrichment of the probiotic genus Ligilactobacillus and the consequent increase in isovaleric acid production.This process coordinately modulates mucosal immunity,cytokine networks,and immune organ function.The elucidation of this“microbiota-metabolite-immunity”axis provides both a pharmacological basis for the clinical application of YZG and novel immune-restorative strategies targeting gut microecological regulation.
基金
supported by the Research Fund Project of the Education Department of Yunnan Province(No.2023Y0464)
Research Project for Scientific Research Funds of Provincial Research Institutions in Heilongjiang Province(No.CZBZ2025ZR003).
