Associations of Inosine with Gut Microbiota, Metabolic Indicators, and Fluid Homeostasis in Kidney-Related Diarrhea.

As a natural purine metabolite, inosine's impact on kidney-related diarrhea through its influence on gut microbiota and associated metabolic functions remains unclear. Kidney-related diarrhea was induced in male KM mice. Histopathological alterations and inflammatory infiltration were assessed using hematoxylin and eosin (HE) staining. ELISA was used to measure corticosterone (CORT), antidiuretic hormone (ADH), and adenosine triphosphate (ATP) to assess metabolic status and fluid homeostasis. Immunohistochemistry (IHC) staining techniques, Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR), and Western blot (WB) were used to analyze the expression of aquaporin-4 (AQP4), AMP-activated protein kinase (AMPK), nuclear factor kappa-B (NF-κB), and adenosine A2A Receptor (A2AR). Gut microbiota composition and predicted functional pathways were analyzed using 16S rRNA sequencing and KEGG-based functional prediction, followed by correlation analyses between the microbiota and factors. Inosine improved renal function, alleviated renal and colonic histopathological damage, and reduced inflammatory infiltration. It also increased ATP, ADH, and CORT levels, indicating improvements in metabolic and fluid-balance-related factors. Inosine also increased A2AR, AMPK, and AQP4 expression while decreasing NF-κB expression. Moreover, inosine altered gut microbial composition and was associated with differences in predicted microbial functional pathways. Significant correlations were observed between specific bacterial taxa and host indicators. Inosine alleviated kidney-related diarrhea in mice, accompanied by improvements in metabolic status and fluid homeostasis, reduced inflammation, modulation of A2AR/AMPK/NF-κB-related signaling pathway, and alterations in gut microbial composition. Further studies are required to clarify the causal contributions of gut microbial composition and functional activity to the beneficial effects of inosine.