The improving-intestinal-microbial-balance properties of lactic acid bacteria (LAB) are well known. Thus, LAB could play a vital role in the pathogenesis of liver diseases. In the present study, 107 LAB strains were isolated from Mongolian camel milk products and identified to species, then screened for their probiotic properties. As a result, we identified 71 Lactobacillus bacteria belonging to 9 different species, and 36 Lactococcus bacteria belonging to 8 different species. Among them, six strains of LAB with strong tolerance and adhesion ability were further studied for their protective effect on acute liver injury induced by lipopolysaccharide (LPS)/D-galactosamine (D-GalN). These six strains of LAB were fed to mice for 7 weeks, and on the final day of the experiment, LPS/D-GalN were used to induce acute liver injury. After challenging, the degree of liver pathological changes, secretion of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum and liver, and the expression of tumour necrosis factor (TNF)-α and interleukin (IL)-6 in the liver and intestines were observed and quantified. The results showed that the degree of liver pathological changes in mice fed with the six LAB strains were relieved to varying degrees compared with the LPS/D-GalN-induced model group, and the expressions of AST, ALT, IL-6, and TNF-α factor were also significantly decreased. Moreover, the expression levels of these factors in mice pretreated with Lactobacillus paracasei subsp. paracasei WXD5 were significantly decreased compared with other experimental groups. This suggests the probiotic potential and pharmacological value of L. paracasei subsp. paracasei as a liver injury inhibitor in the intervention of inflammation-based liver disease.
Keywords: acute liver injury; inflammation; lactic acid bacteria; probiotic.