Protective effects and antioxidant mechanisms of lactobacillus combined with carnosine on the stomach and small intestine

Oxidative stress is intricately related to gastrointestinal diseases. Although both lactobacillus (LAB) and carnosine (CAR) contribute to combating oxidative stress and attenuating gastrointestinal disorders, little is known about the effects and mechanisms of their combined treatment. Here, we report the protective effects of LAB and/or CAR on the gastrointestinal tissues in normal or dexamethasone (Dex)-induced stress mice. The combination of LAB and CAR protected the structures of stomach and small intestine, alleviating the Dex-induced tissue damages. Additionally, this combined treatment increased the activity of antioxidant enzymes and up-regulated the expression of antioxidant genes in the Nrf2 signaling pathway in stress mice. Our study sheds light on the synergetic and complementary roles of LAB and CAR in maintaining the structural and functional integrity of stomach and small intestine, offering clues for understanding the regulation of antioxidant enzyme genes through the Nrf2 pathway as a potential mechanism. • Dexamethasone treatment causes oxidative damage to gastrointestinal tissues in mice. • Lactobacillus combined with carnosine can synergistically alleviate the gastrointestinal tissues damage in stressed mice. • Lactobacillus and carnosine reduce dexamethasone-induced oxidative damage by regulating antioxidant enzymes in Nrf2 pathway.