Experimental Study Of Berberine Improving Lipopolyccharide-induced Intestinal Mucosal Barrier Damage And Its Possible Mechanisms

1.Objectives1)To study the effect of LPS on the intestinal epithelial permeability and the expression of the tight junction proteins;2)To validate whether the influence of LPS on the intestinal epithelial permeability has to do with the apoptosis of intestinal epithelial cell;3)To study the protective effect of berberine on the intestinal epithelial barrier dysfunction induced by LPS and possible mechanisms and to preliminarily explore the role of TLR4-My D88-NF-?B in it.2.Method1)Caco-2 cell cultured in transwell chamber were used as the model of intestinal mucosa barrier;2)The effect of LPS and BBR on the cell viability were detected by MTT method;3)Trans-epithelial electrical resistance(TER)was measured with EVOM resistance instrument and FITC-Dextran permeability was measured with ELIASA;4)The expression of caspase12,TJ proteins(zo-1,occludin and claudin1)and TLR4 pathway proteins including TLR4,My D88 and NF-?B were measured with western blot;5)The distribution of TJ proteins including zo-1 and claudin1 were on Caco-2 cell membrane was observed by immunofluorescence technique.3.Result1)Compared with control group,high concentration of LPS(100?g/m L)and BBR(>20?M)stimulate caco-2 cell for 24 hours,the cell viability decreased significantly(P<0.05).2)Compared with control group,LPS(0.1-10?g/m L)didn't cause significant change on protein caspase12 related with apoptosis(P>0.05).3)Compared with control group,LPS(0.1-10?g/m L)increased significantly the intestinal epithelial permeability(P<0.05);meanwhile intestinal epithelial permeability increased with the increase of the concentration of LPS.4)Compared with the LPS group(10?g/m L),the intervention group(BBR 10?M)decreased markedly the intestinal epithelial permeability(P<0.05).5)Compared with control group,the LPS group(10?g/m L)significantly decreased the expression of the tight junction proteins including zo-1,occludin and claudin1;while compared with the LPS group,the expression of these TJ proteins in the intervention group has a sharp increase(P<0.05).6)Compared with control group,the LPS group(10?g/m L)significantly increased the expression of TLR4,My D88 and NF-?B;while compared with the LPS group,the expression of these proteins significantly deccreased(P<0.05).4.Conclusion1)LPS of 0-10?g/m L induced Intestinal epithelium permeability increased,which has closely relationship with paracellular pathway(tight junction proteins expression)rather than transcellular pathway(cell apotosis);2)Berberine inhibited LPS-induced intestinal epithelium permeability increasing,which is related to increasing expression of TJ proteins;3)The decreased expression of TJ proteins induced by LPS may result from activating signal pathway including TLR4,My D88 and NF-?B,while berberine can improve this situation via inhibiting the signal pathway.