Kidney protective effect of fermented celery polysaccharides and Eubacterium rectale in diabetic rats

This study aimed to investigate the protective effects of non-fermented celery polysaccharides (NFCP), fermented celery polysaccharides (FCP), Eubacterium rectale (ER), and their combined intervention (ER+FCP) on Type 2 diabetes (T2D)-related kidney injury in a rat model, using untargeted urinary metabolomics and kidney function indices. We employed ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC–QTOF/MS) to analyze urinary metabolite profiles. Principal component analysis (PCA) demonstrated significant metabolic disturbances in the diabetic group (DM), while all intervention groups showed a shift towards a healthier metabolic profile, with ER and ER+FCP exhibiting the most pronounced improvements. Metabolic alterations in the intervention groups were further validated by differential metabolite analysis, with FCP inducing a larger number of significant changes compared to NFCP. The combined intervention (ER+FCP) showed synergistic effects, enhancing lipid metabolism, inflammation resolution, and the regulation of bile acids, all contributing to kidney protection. Inflammatory markers, oxidative stress, and histological analysis confirmed the efficacy of these interventions in mitigating kidney injury. Our findings highlight the potential of fermented celery polysaccharides and ER to provide enhanced protection against diabetic kidney disease through metabolic modulation and synergistic interactions.