Multispecies probiotic protects gut barrier function in experimental models
摘要
AIM:To investigate the effect of the probiotic combination Lactibiane Tolerance?(LT)on epithelial barrier function in vitro and in vivo.METHODS:The effect of the multispecies probiotic LT was assessed on several models of epithelial barrier function both in vitro(in basal and inflammatory conditions)and in vivo[visceral hypersensitivity induced by chronic stress or by colonic perfusion of a fecal supernatant(FSN)from patients with irritable bowel syndrome(IBS)].In vitro,we measured the permeability of confluent T84 cell monolayers incubated with or without LT by evaluating the paracellular flux of macromolecules,in basal conditions and after stimulation with lipopolysaccharide(LPS)or with conditioned medium of colonic biopsies from IBS patients(IBS-CM).In vivo,male C57/Bl6 mice received orally NaCl or LT for 15 d and were submitted to water avoidance stress(WAS)before evaluating visceral sensitivity by measuring the myoelectrical activity of the abdominal muscle and the paracellular permeability with 51Cr-EDTA.Permeability and sensitivity were also measured after colonic instillation of FSN.Tight-junctions were assessed by immunoblotting and TLR-4 expression was evaluated by immunohistochemistry RESULTS:Incubation of T84 cell monolayers with LT in basal conditions had no significant effect on permeability(P>0.05 vs culture medium).By contrast,addition of LT bacterial bodies(LT)completely prevented the LPS-induced increase in paracellular permeability(P 0.05 vs culture medium).The effect was dose dependent as addition of 109 LT bacterial bodies induced a stronger decrease in absorbance than 106 LT(109 LT+LPS 10:-20.1%±13.4,P<0.01vs LPS 10;106 LT+LPS 10:-11.6%±6.2,P<0.01 vs LPS 10;109 LT+LPS 100:-14.4%±5.5,P<0.01 vs LPS 100;106 LT+LPS 100:-11.6%±7.3,P<0.05 vs LPS 100).Moreover,the increase in paracellular permeability induced by culturing T84 cells with conditioned medium of colonic biopsies from IBS patients(IBS-CM)was compl