Ethanol extract of Lactobacillus rhamnosus AC1-fermented soymilk alleviated DSS-induced colitis via LPS-TLR4-NF-κB signaling pathway

Abstract

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disorder associated with a variety of factors including environmental, genetic, gut flora and immune factors. Our previous studies showed that soymilk fermented by Lactobacillus rhamnosus AC1 harbors anti-inflammatory and antioxidant effects. This study aimed to further investigate the beneficial effects of ethanol extract (EE) of L. rhamnosus AC1-fermented soymilk on dextran sulfate sodium (DSS)-induced colitis mice via LPS-TLR4-NF-κB signaling pathway and improvement of gut microbiota dysbiosis. Low dose of EE (200 mg/kg), high dose of EE (400 mg/kg), and anti-colitis drug, 5-Amino Salicylic Acid (5-ASA, 200 mg/kg), were used as the interventions in DSS-induced acute colitis. EE of L. rhamnosus AC1-fermented soymilk significantly alleviated body weight loss, disease activity index (DAI) scores, and histopathological damage. In addition, EE reduced apoptosis, increased proliferation, alleviated mucosa barrier damage, and down-regulated LPS-TLR4-NF-κB signaling pathway in DSS-induced colitis mice. Furthermore, the gut microbiota dysbiosis induced by DSS treatment was partially restored by EE treatments, especially in Proteobacteria and its lower taxa. In conclusion, the present study demonstrated that EE of L. rhamnosus AC1-fermented soymilk is a promising dietary intervention strategy to prevent DSS-induced colitis through down-regulation of LPS-TLR4-NF-κB signaling pathway and reverting gut microbiota dysbiosis.