Abstract: Objective: To study the protective effect of Lactobacillus plantarum Sc52 on lipopolysaccharide (LPS)-induced mouse intestinal barrier injury. Methods: Six-week-old male ICR mice were randomly divided into 3 groups. L. plantarum Sc52 was fed to the mice in the experimental group by gavage at a dose of 1010 CFU/d for 14 consecutive days, while the mice in the control and model groups were given an equal volume of normal saline. Then, all mice except those in the control group were intraperitoneally injected with LPS to establish an intestinal barrier injury model. The levels of inflammatory cytokines in serum and intestinal permeability-related parameters were measured by enzyme-linked immunosorbent assay (ELISA). The histopathological changes of the ileum were tested by hematoxylin-eosin staining. The contents of shortchain fatty acids in colonic contents were determined by gas chromatography and the major intestinal bacteria in feces were enumerated by plate counting. The expression of intestinal tight junction protein was examined by Western blot. Results: Intragastric administration of L. plantarum Sc52 could inhibit the increase of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-12 (IL-12) and nitric oxide (NO). In addition, L. plantarum Sc52 could improve intestinal permeability by regulating D-lactic acid and diamine oxidase levels in the serum of mice. Furthermore, after administration of L. plantarum Sc52, the contents of acetic acid and butyric acid in colonic contents were increased, the number of Lactobacilli, Bifidobacterium and other beneficial microorganism were also significantly increased, and the number of harmful bacteria was decreased. Moreover, the expression of tight junction protein in the ileum was up-regulated. Conclusion: L. plantarum Sc52 can effectively protect against intestinal barrier injury caused by LPS in mice.

Key words: probiotics, Lactobacillus plantarum, gut barrier, permeability, inflammation