Study Of Tea Polyphenols On The Barrier Function And Regulation Of Immune Response In Intestinal Porcine Epithelial Cells

Tea polyphenols(TP)are polyphenols in Tea.Tea polyphenols have the functions of anti-oxidation,anti-cancer,regulating the development of immune organs and immue system,increasing the beneficial bacteria in the intestinal tract and inhibiting and killing various harmful pathogenic bacteria causing diarrhea to ease gastrointestinal tension and anti-inflammatory antidiarrheal and so on.Enterotoxigenic Escherichia coli(ETEC)K88 is one of the important causes of diarrhea in newborn piglets,it can damage the intestinal epithelial barrier and cause a series of inflammatory reactions by adhesion to the intestinal epithelial cells through its own adhesive hormone.Studies have shown that tea polyphenols are effective in fighting intestinal infections,and can regulate the growth and development of immune organs and alleviate the body injury in model animals induced by injury by regulating the expression of toll-like receptor.However,whether it can resist the infection of ETEC K88 and alleviate the intestinal inflammation caused by it has not been reported.In this paper,the effects of tea polyphenols on intestinal epithelial barrier function and inflammatory response in pigs were studied by in vitro cell test and in vivo mouse test.The details are as follows: 1.The effects of tea polyphenols on the biological characteristics of ECET K88 and the conditions of its interaction with IPEC-J2 cellsThe bacteriostatic test showed that TP had bacteriostatic activity,The MIC value of TP for ETEC K88 is 5.0 mg/m L,and that of MBC is 10.0 mg/m L.Moreover,TP could significantly inhibit the adhesion of ETEC K88 to IPEC-J2 cells.At the same time,the optimal conditions of TP-IPEC-J2-ETEC K88 interaction were explored: IPEC-J2 cells were pre-treated with a concentration of 0.5 mg/m L TP for 3 h,and then challenged with ETEC K88,MOI = 10,for 3 h.2.Study on the regulation of tea polyphenols in the cell barrier function of IPEC-J2 induced by ETEC K88.Q-pcr and Western blotting were used to detect the effects of TP on the expression of tight junction protein in IPEC-J2 cells infected with ETEC K88,The results showed that: Compared with the ETEC K88 group,TP could significantly inhibited the down-regulation expression of claudin-1,and had no significant effect on the expression of ZO-1 and occludin in IPEC-J2 cells,induced by ETEC K88.This indicated that TP can alleviate the destruction of tight junction protein claudin-1 in IPEC-J2 cells,infected with ETEC K88.3.Study on the regulation of tea polyphenols in the inflammatory response of IPEC-J2 cells infected with ETEC K88Q-pcr was used to detect the effects of TP on the m RNA expression of genes of inflammatory,TLR2 and negative regulators of TLRs,in IPEC-J2 cells,infected with ETEC K88,The results showed that: TP could significantly inhibited down-regulation expression of anti-inflammatory cytokines IL-10,TLR2,TOLLIP and A20,the negative regulators of TLR signaling pathway,and the up-regulation expression of pro-inflammatory cytokines,IL-2,IL-6,IL-8,in IPEC-J2 cells.But the expression of TNF-? was significantly up-regulated after pre-treatment with TP.In addition,TP had no significant effect on the down-regulation of the negative regulator of the TLR signaling pathway,IPAKM,and the expression of TGF-? and Bcl3 in IPEC-J2 cells.This suggests that TP may regulate the inflammatory response by regulating the expression of inflammatory cytokines and the TLR signaling pathway in cells.4.Study on the effect of tea polyphenols on inflammatory response in miceThrough the construction of mouse inflammatory model,it was found that Compared with mice infected with ETEC K88 in control group,mice infected with ETEC K88 in TP addition group had less clinical symptoms and no significant changes in intestinal dissection.HE staining showed mild degeneration of intestinal mucosal epithelial cells.The expression of TNF-a in serum was significantly up-regulated and the expression of IL-6 was significantly down-regulated.This indicated that TP can relieve the inflammatory response in mice induced by ETEC K88.