Screening of Lactic Acid Bacteria Strains from Chinese Fermented Food (Suanshui) and its Protective Effect on Acute Liver Injury in Mice.

Abstract

Suanshui is a traditional fermented vegetable food in the southwest of China that is a rich source of probiotics. This study aimed to screen probiotics from Suanshui that have a protective effect against liver injury using in vivo and in vitro experiments. Eleven strains were isolated according to acid-producing capacity and probiotic properties, including antibacterial activity against pathogenic bacteria, tolerance to artificial gastrointestinal fluid and bile salts, heat resistance, antioxidant capacity, hydrophobicity, autoaggregation capacity, and adhesion capacity. Three probiotic strains, LAB36 (Lacticaseibacillus paracasei, (L. paracasei)), LAB19 (Lactiplantibacillus plantarum (L. plantarum)), and LAB51 (Limosilactobacillus fermentum (L. fermentum)), were obtained by the TOPSIS comprehensive evaluation. Furthermore, in an in vitro model of inflammation induced by LPS treatment of AML12, metabolites derived from the intestinal contents of mice treated with the three strains significantly decreased the gene expression of IL-1β, TNF-α, and Caspase 3 in the LAB (19, 36, 51) + LPS group (P < 0.05) and significantly increased the gene expression of Bcl-2 compared with those in the untreated LPS group (P < 0.05). In addition, the LAB36 + LPS group also exhibited significantly decreased gene expression of TLR4 and Bax (P < 0.05). In vivo experiments, LAB36 pretreatment significantly decreased the levels of ALT, AST, and inflammatory factors (IL-1β and IL-6) in the serum, improved the antioxidant capacity, and reduced apoptosis in the livers of the model mice (liver injury induced by D-GalN/LPS). In summary, LAB36 isolated from Suanshui has a protective effect on liver injury.