Bifidobacterium longum subsp. longum B-53 Alleviated Abnormalities of Glycolipid Metabolism and Oxidative Stress in T2DM Mice Through Regulating Gut Microbiota and GLP-1 Secretion

Creating effective treatments for type 2 diabetes mellitus (T2DM) remains a critical global health challenge. This study investigates the antidiabetic mechanisms of Bifidobacterium longum subsp. longum B-53 (B. longum B-53) in T2DM mice. Results showed that B. longum B-53 improved glucose homeostasis, reducing hemoglobin A1c from 317.2 ± 8.8 nmol/L to 168.3 ± 6.4 nmol/L and decreasing oral glucose tolerance test AUC (p < 0.05). B. longum B-53 outperformed metformin in regulating lipids and reducing weight, low-density lipoprotein cholesterol, total cholesterol, and triglycerides while increasing HDL-C. Systemic inflammation was reduced with elevated interleukin-10 (p < 0.05). B. longum B-53 improved the intestinal barrier function, decreased oxidative stress, ameliorated hepatic steatosis, and raised insulin levels. Mechanistically, B. longum B-53 reshaped gut microbiota, enriched indole metabolites, activated AhR/GLP-1/PDX-1 signaling to boost GLP-1 secretion, and regulated hepatic InsR/PI3K/Akt and AMPK/SREBP-1c pathways for glucose/lipid metabolism. These findings support B. longum B-53 as a promising functional food for metabolic disorders.