Ameliorative Effects of Probiotic Lactobacillus paracasei NL41 on Insulin Sensitivity, Oxidative Stress, and Beta-Cell Function in a Type 2 Diabetes Mellitus Rat Model

Scope The present study aims to assess the antidiabetic effect of Lactobacillus paracasei strain NL41 and its potential mechanisms in rats with type 2 diabetes mellitus (T2DM) induced by a high-fat diet and low-dose streptozotocin administration (HFD/STZ). Methods and results Eighteen Sprague-Dawley (SD) rats are randomly assigned to three groups: one control, one HFD/STZ model, and one HFD/STZ-Lactobacillus protection group with administration of strain NL41 for 12 weeks. Blood is collected for biochemical parameters analysis and tissue samples for histological analysis. Treatment with strain NL41 results in excellent blood glucose regulation and significantly decreases insulin resistance, and HbA1c, glucagon, and leptin levels, accompanied by remarkable improvement of dyslipidemia and oxidative stress status in the animals. Islets of Langerhans, liver, and kidney are significantly protected in the NL41-treated rats compared to the HFD/STZ-T2DM model rats. Histochemistry shows that strain NL41 inhibits beta-cell loss and alpha-cell expansion, indicating pancreatic islets as the targeted tissues for the primary ameliorative effect of the probiotic strain on HFD/STZ-T2DM rats. Crosstalk between the gut-liver and liver-pancreas endocrine axes is discussed. Conclusion Probiotic strain NL41 prevents HFD/STZ-T2DM by decreasing insulin resistance and oxidative stress status, and protecting beta-cell function.