Effects of Bacillus subtilis natto JLCC513 on gut microbiota and intestinal barrier function in obese rats

This study aimed to investigate the effects of Bacillus subtilis natto JLCC513 (JLCC513) on gut microbiota, inflammation and intestinal barrier function in high-fat-diet (HFD) rats.Sprague-Dawley (SD) rats were fed HFD for 16 weeks, and treated with JLCC513 in 9th week. The oral administration of JLCC513 decreased body weight and reduced the inflammation level in HFD rats. Pathologically, JLCC513 prevented the detachment of ileal villus and increased the villus height in rats. Mechanistically, western blot analysis showed that the protein levels of tight junction (TJ) proteins involved in intestinal barrier function, including zonula occludens-1 (ZO-1), occludin and claudin-1, were increased after JLCC513 treatment. Meanwhile, JLCC513 treatment also decreased the protein levels of toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB) and NOD-like receptor protein 3 (NLRP3), indicating inhibition of the TLR4/NF-κB/NLRP3 pathway. Furthermore, faecal analysis showed that JLCC513 increased the abundance of Lactobacillus and Oscillospira and the ratio of Firmicutes/Bacteroidetes (F/B), and decreased the levels of Blautia and C_Clostridium.JLCC513 alleviated intestinal barrier dysfunction by inhibiting TLR4/NF-κB/NLRP3 pathway and regulating gut microbiota disorders.Our study might provide new treatment strategies for obesity and metabolic diseases.