The Mechanism Of ORP-1 In Improving Intestinal Mucosal Barrier Function

Gastrointestinal mucosa covers a vast area of the human body.As the largest surface for human body to contact with the external environment,it is not only a place for food processing,but also provides a living environment for symbiotic microorganisms while inhibiting pathogenic microorganisms.The barrier of intestinal mucosa protects the gastrointestinal mucosa,that is important to maintain the balance and health of the gastrointestinal tract and the body.Intestinal mucosal barrier can ensure that the body absorbs nutrients while preventing the infiltration of some pathogenic microorganisms.With the aging of the body,the intestinal mucosal barrier is also damaged,so it is an urgent problem for us to improve the defect of the intestinal mucosal barrier caused by aging.Oudemansiella raphanipes is a kind of rare edible and medicine fungus.ORP is the active substance extracted from it.Our laboratory previously found that ORP can improve the intestinal mucosal barrier of aging mice,and homogeneous polysaccharide ORP-1 has prebiotic properties.However,whether ORP-1 can improve the intestinal mucosal barrier damage caused by aging and how to improve the intestinal mucosal barrier have not been reported.Therefore,in this paper,Caco-2 cells were used to establish an intestinal epithelial cell model to explore the effect of ORP-1 on intestinal mucosal barrier function.The main research contents and results are as follows:1.D-gal was used to induce Caco-2 cells to establish the aging model of intestinal epithelial cells.D-gal increased the activity of β-galactoside in Caco-2 cells,decreased the mitochondrial membrane potential.It increased the protein and gene expression level of P53 compared with the normal group.It also decreased the expressions of Occludin and ZO-1.Subsequently,we found that ORP-1 can improve intestinal senescence by inhibiting the decrease of mitochondrial membrane potential and reducing the generation of senescent cells.2.The effect of ORP-1 on biological barrier function was investigated by in vitro proliferation and adhesion experiments.We found that ORP-1,as a prebiotic,can promote the proliferation and the adhesion to intestinal epithelial cells of two intestinal probiotics Bifidobacterium bifidum and Lactobacillus acidophilus.Meanwhlie,ORP-1 can regulate the intestinal mucosal barrier by inhibiting the proliferation and adhesion to intestinal epithelial cells of conditioned intestinal pathogen Escherichia coli.3.By measuring the transmembrane resistance of Caco-2 cells,we found that D-gal induced intestinal epithelial cell aging led to a decrease in TEER,which destroyed the intestinal mucosal barrier,and the decrease of TEER could be inhibited after ORP-1pretreatment.4.Western Blotting and RT-PCR showed that D-gal induced senescence of Caco-2 cells resulted in decreased protein and gene expression of Occludin and ZO-1 in intestinal epithelial cells.After ORP-1 pretreatment,the expression of Occludin and ZO-1 were significantly increased.So,we speculate that ORP-1 ameliorates the intestinal mucosal barrier by regulating the tight junctions between intestinal epithelial cells.In conclusion,ORP-1 can improve intestinal mucosal barrier damage caused by aging by regulating intestinal biological barrier and mechanical barrier.