Probiotics Alleviate Oxidative Stress in H₂O₂-Exposed Hepatocytes and t-BHP-Induced C57BL/6 Mice

Antioxidants protect against oxidative stress that can damage proteins, the cellular immune system, and DNA. In recent studies, probiotics have been shown to impart a microbial balance to the gastrointestinal tract, demonstrating significant antioxidant capacity. In this study, the probiotic properties and antioxidant mechanism of probiotics were evaluated in HepG2 cells and in an animal model. The characteristics of Lactococcus lactis MG5125, Bifidobacterium bifidum MG731, and Bifidobacterium animalis subsp. lactis MG741, which were used as lactic acid bacteria in this study, were analyzed. The results revealed the safety and stability of these probiotics in the gastrointestinal tract because they did not cause hemolysis and had excellent intestinal adhesion (75-84%). In HepG2 cells, the three probiotics alleviated H₂O₂-induced oxidative stress by mediating lipid peroxidation and glutathione levels and upregulating antioxidant enzymes, including catalase, superoxide dismutase, and glutathione peroxidase. In the tBHP-induced mouse model, administration of the three probiotics reduced hepatic aspartate transaminase, alanine transaminase, and lipid peroxidation levels. In conclusion, Lc. lactis MG5125, B. bifidum MG731, and B. lactis MG741 showed considerable antioxidant activity both in vitro and in vivo.