Commensal Microbiota Regulation of Metabolic Networks During Olfactory Dysfunction in Mice

Introduction: Recently, an increasing number of studies have focused on commensal microbiota. These microorganisms have been suggested to impact human health and disease. However, only a small amount of data exists to support the assessment of the in fl uences that commensal microbiota exert on olfactory function. Methods: We used a buried food pellet test (BFPT) to investigate and compare olfactory functions in adult, male, germ-free (GF) and speci fi c-pathogen-free (SPF) mice, then examined and compared the metabolomic pro fi les for olfactory bulbs (OBs) isolated from GF and SPF mice to uncover the mechanisms associated with olfactory dysfunction. Results: We found that the absence of commensal microbiota was able to in fl uence olfactory function and the metabolic signatures of OBs, with 38 metabolites presenting signi fi cant differences between the two groups. These metabolites were primarily associated with disturbances in glycolysis, the tricarboxylic acid (TCA) cycle, amino acid metabolism, and purine catabolism. Finally, the commensal microbiota regulation of metabolic networks during olfactory dysfunction was identi fi ed, based on an integrated analysis of metabolite, protein, and mRNA levels. Conclusion: This study demonstrated that the absence of commensal microbiota may impair olfactory function and disrupt metabolic networks. These fi ndings provide a new entry-point for understanding olfactory-associated disorders and their potential underlying mechanisms.