Isolation And Screening Of Probiotics Lactobacillus And The Study For Protection Of Lipopolysaccharide-Induced Acute Liver Injury

Lactic acid bacteria(LAB)are concerned by many researchers because of their superior properties.In this study,the LAB which isolated from dairy products were preliminarily identified by the morphological characteristics,catalase contact and Gram staining test,then were identified by the 16SrDNA sequence analysis,physiological and biochemical characteristics and carbohydrate fermentation test.And the potential probiotic strains were screened by artificial gastric juice tolerance,bile salt tolerance and adhesion ability test.Finally,the six strains of LAB were fed to mice,and used the LPS/D-GalN to induce acute liver injury.After challenging,by observing the changes of body weight?liver pathological changes and weight,the secretion of AST and ALT in serum and liver,the expression of TNF-a and IL-6 in liver and intestinal,to study the protective effect of the six strains on acute liver injury induced by LPS/D-GalN.Results:1.107 LAB strains were isolated from the dairy products,including of the 71 Lactobacillus lactis strains belonging to the nine species and the 36 Lactococcus lactis strains belonging to the eight species:Lactobacillus brevis,Lactobacillus paracasei subsp.paracasei,Lactobacillus gallinarum,Lactobacillus fermentum,Lactobacillus reuteri,Lactobacillus helveticus,Lactobacillus plantarum subsp.Argentoratensis,Lactobacillus delbrueckii,Lactobacillus diolivorans,Pediococcus pentosaceus,Leuconostoc mesenteroides,Pediococcus acidilactici,Lactococcus.sp,Leuconostoc.sp,Enterococcus.sp,Enterococcus faecalis,Pediococcus.sp.2.Most of the strains were homofermentative species and some were heat-or cold-resistant strains.3.We screened the six strains of LAB with strong tolerance and adhesion ability from 139 strains by artificial gastric juice tolerance,bile salt tolerance and adhesion ability tests,they were L.paracasei subsp.paracasei WXD5,L.casei SXJ30,L.plantarum subsp.argentoratenis WXD55,L.plantarum subsp.argentoratenis WXD100,L.plantarum subsp.argentoratenis WXD101,L.plantarum subsp.argentoratenis WXD106.4.We studied the six LAB strains of protective effect on acute liver injury induced by LPS/D-GalN.The results showed that the degree of liver pathological changes of mice fed with WXD5,WXD55,WXD100,WXD101,WXD106,SXJ30 were relieved in different degree compared with the model group,and the AST,ALT,IL-6 and TNF-a factor expression were also decreased significantly.Moreover,the expression levels of the related factors in mice fed with WXD5 were significantly decreased than other experimental groups and the WXD5 had the most obvious protective effect,it can provide technical support and theoretical basis for the study of acute liver injury.