Effects Of Lactobacillus Rhamnosus Lactobacillus Lactobacillus Lambda L

As important probiotics in human intestinal, lactic acid bacteria played an important role in inhibiting pathogenic bacteria, regulating the immune function, maintaining the balance of intestinal microecological through interaction with the intestinal mucosal immune system. The normal metabolism of the host would be disturbed when the balance of intestinal flora wes damaged, which could cause disease. In the paper, LAB were screened from the fecal of longevity population from Bama, Guangxi province and Hetian, Xinjiang in China in vitro, and the role in regulating immunity in vivo. RT-PCR and NMR spectrum technology were used to investigate the effect of LAB on intestinal microflora and metabolism of immunocompromised rats, thus providing help for probiotics to intervention sub-healthy diet.(1) LAB were screened from the fecal of longevity population from Bama, Guangxi province and Hetian, Xinjiang in China, the ability of hydrophobic, cell adhesion, tolerating acid and bile, antibacterial and tolerating antibiotics were studied. The results showed that, the ability of surface hydrophobicity and cell adhesion of 10 strains LAB were stronger. A further study found that, the survival rates of PW1, LV108 and XJH301 were 34.08%,61.35%,47.15% respectively by culturing in the artificial gastric juice of pH2.0 for 2h, the survival rates were 61.42%,86.03%,55.03%、respectively by culturing in the artificial intestinal fluid for 4h, the survival rates were 49.36%,45.24%,37.19、respectively by culturing in MRS medium containing 0.3% bile salt in the 10 strains of LAB, which were significantly higher than other strains(P<0.05). The antibacterial circles for E.coli of PW1, LV108 and XJH301 were 16.76mm, 20.49mm,14.35mm, the antibacterial circles for Salmonella were 13.23mm,17.19mm,10.63mm, the antibacterial circles for Staphylococcus were 11.76mm,14.01mm,10.10mm. LV108 was sensitive to 5 antibiotics, namely rifampicin, tetracycline, cefazolin, chloramphenicol, cefradine, and moderately sensitive to streptomycin, the ability of tolerating antibiotic was lower than other strains. LV108 was identified as Lactobacillus rhamnosus by API and 16S rDNA sequencing.(2) Immunosuppressive model was established by intraperitoneal injection of 40mg/kg cyclophosphamide for 3 consecutive days, with levamisole as a positive control. The body weight increased slowly and the growth of thymus were inhibited of immunocompromised rats. The content of IL-2, IgG, IgA and the hemolysin in serum reduced significantly(P<0.05), the carbon clearance index and phagocytic index were significantly lower than the control group(P<0.05). The number of splenic lymphocytes decreased significantly(P<0.05).The rats were intervention for 4 weeks, and the results showed that cell suspension and fermented milk of L. rhamnosus LV108 could improve the spleen and thymus index significantly(P<0.05), increase the content of IL-2, IgG significantly(P<0.05), stimulate the differentiation and proliferation of B lymphocyte and improve the content of serum hemolysin, increase the carbon clearance index and phagocytic index significantly(P<0.05), which improve the function of mononuclear phagocyte system in rat, promote tehe proliferation of lymphocyte, and participate in the immune response of spleen lymphocytes in rats.(3) RT-PCR was used to study the changes of intestinal flora in rats. The results showed that, compared with the control group, the intestinal flora of immunocompromised rats changed, wherein the content of lactic acid bacteria and bifidobacteria decreased significantly(P<0.05), and the content of enterobacteriaceae and enterococci increased significantly(P<0.05). The rats were intervention for 4 weeks, and the results showed that the cell suspension and fermented milk of L. rhamnosus LV108 could decrease the content of enterobacteriaceae and enterococci significantly(P<0.05), and increase the content of lactic acid bacteria and bifidobacteria significantly(P<0.05). The magnitude of improvment on the intestinal flora in rats by the fermented milk of L. rhamnosus LV108 was greater than the cell suspension of L. rhamnosus LV108, which suggesting that living cells LV108 could not only play a role by itself, but also improve the intestinal flora through their metabolites.The content of lactic acid bacteria in the intestinal of rats showed a significant positive correlation with the level of TNF-a and IgA by correlation analysis(P<0.05).(4) NMR spectrum technology was used to study the changes of the intestinal metabolites in rats. The results showed that, compared with the control group, the content of isoleucine, alanine, butyric acid, succinic acid, creatine phosphate, trimethylamine oxide, taurine, β-glucose, a-glucose, uracil and other ingredients in immunocompromised rats fecal. The rats were intervention for 4 weeks, and the results showed that the cell suspension and fermented milk of L. rhamnosus LV108 incresaed the content of isoleucine, alanine, lysine and the other amino acids, which improved the amino acid metabolism and energy metabolism in rats. They also increased the content of organic, such as lactic acid and succinic acid, which inhibited the growth of pathogenic bacteria in the gut. They could also increase the content of a-glucose, N-acetyl glycoproteins, TMA, β-glucose and other components to improve the metabolism of the intestinal flora.