Preliminary Research For The Effect On Intestinal Barrier Treated With Intestinal Bacteria

Intestinal tract,a very important organ for human life,plays a key role for digestion and absorbing.Because of its function,it is touched with many microbiology and the microbiology which adhered with intestinal tract could affect its function.Most of intestinal probiotic bacterium are able to regulate the ability and function of intestinal epithelial and dendritic cells,which promote human health.However,host disease is led by many intestinal pathogenic bacteria.There are many kinds of intestinal microbiology,and it is different to distinguish through its own characteristics.Generally,intestinal instruction is protected by probiotic,but broken by pathogenic bacteria.The detailed molecular mechanism is not clear about this reaction.According to all of above,six strains(Bifidobacterium animals,Lactobacillus rhamnosus,Lactobacillus plantarum,Esherichia coli O157:H7,Salmonella Typhimurium and Listeria monocytogenes)were selected.The tight junction structure of intestinal epithelial cell and the permeability of mouse intestinal tract were researched after treated with six strains respectively.Meanwhile,using RNA-sequencing technology,we find the different express genes in intestinal epithelial cell after treated six strains respectively.Two strains of mice were selected for permeability research.The results were shown that the permeability of Balb/c and Kunming mouse intestinal tract were maintained treated with probiotics in this research,the relative permeability value were decreased for 3.14%,20.9%,33.5% and 59.9%,59.1%,55.5% respectively in4 h.in Addition,after treated with strains 2h and 4h,the ability of maintaining was obviously in Balb/c or Kunming mouse.The ability of maintaining permeability of intestinal tract is strain and issue specificity.The permeability was destroyed after treated by pathogens in this research,specially treated after 2h.Relative value was increased for 30.9%,61.1%,48.7% in 4 h and 50.8%,183.3%,102.6% in 2 h respectively,which also show strain and issue specificity.The model of tight junction structure was established in transwell by using Caco-2 cell.The TEER value and the concentration of dextran blue 2000 were measured to reflect the change of the tight junction structure and the permeability of mouse intestinal tract after treated with strains respectively.The results were shown that the tight junction structure was maintained and protected after treated by Bifidobacterium animalis,Lactobacillus rhamnosus and Lactobacillus plantarum,relative TEER value was increased for 4.3%,4.3% and 2.9% in 6 h,otherwise the ability of this is different about strains.The tight junction structure was destroyed after treated with pathogenies used in this research.This ability may be related to adhesion and invading of Escherichia coli O157:H7,Salmonella Typhimurium and Listeria monocytogenes,the relative value were decreased for 8.1%,8.2% and 13.1%.In order to the reason of maintaining or destroying for tight junction structure after treated with strains,RT-qPCR technology was used in this research.The expression of ZO-1,Claudin-1 and Occludin were changed,and there are no obvious same rules.High-throughput sequencing technology,also called Next Generation Sequencing technology,is a great progress of DNA sequencing,and it is a foundation technology of RNA-sequencing.We use it to research the change of transcriptional level of Caco-2 cell treat with strain and find out the genes which are different expression.After sequencing and date analyze,we got the information of different express genes.The results were shown that 61 genes were different expression in Caco-2 cell treated with intestinal probiotic and pathogenic bacterium we selected.Meanwhile,22 genes were up-regulated and 39 genes were down-regulated in Caco-2cell treated with probiotic and pathogenic bacterium respectively.The results of this study explored the impact intestinal barrier function treated with microbiology,and it could provide reference for adjuvant therapy of gastrointestinal disease,developing of microecologics and applying of fermented food.Meanwhile,it can be referred to analyze and distinguish the probiotic characteristic of microbiology.