Evaluation of Potential Anti-Diabetic Synbiotic Formulation of Lacticaseibacillus rhamnosus BST.L-601 Using db/db Mice

Probiotics have been studied for their potential to treat chronic diseases. This study examined the use of <i>Lacticaseibacillus rhamnosus</i> BST.L-601 as an anti-diabetic symbiotic with sweet potato for fermentation. The medium supplemented with sweet potato showed increased productivity and enhanced storability. The anti-diabetic effect of fermented BST.L-601 was evaluated using the C2C12 myotube and a type 2 diabetes mellitus (T2DM)-induced db/db (Lepr^db/Lepr^db) mouse model. Treatment with heat-killed BST.L-601 increased glucose uptake by 125% and α-glucosidase inhibition in a dose-dependent manner without cytotoxicity for myotubes. 8 weeks of oral administration of BST.L-601 led to anti-diabetic activities in various biomarkers in the mouse model, including lowered fasting blood glucose by 88% and elevated mRNA expression of glucose metabolism-related factors IRS-1 (510%) and GLUT4 (181%) from skeletal muscle. Moreover, the improvement of induced T2DM in mice was supported by blood serum analysis. Immunohistochemistry showed increased insulin and decreased glucagon secreted from β and α cells in the pancreas islet. Microbiota analysis demonstrated elevated microbiome diversity in mice treated with BST.L-601. Furthermore, the safety and probiotic properties of the strain were confirmed. These results suggest that BST.L-601 fermented with sweet potato could be a functional symbiotic used to improve diabetes, particularly T2DM.