Effect Of Emodin On Intestinal Epithelial Barrier Dysfunction In Rats With Sepsis Induced By CLP And LPS

Objective To investigate the protective effect of emodin on intestinal epithelial barrier injury induced by CLP indirect modeling and LPS direct modeling,and its possible mechanism.Methods Healthy male Sprague?Dawley rats were randomly divided into 8 groups according to different modeling methods(each n=20): CLP modeling mode: Blank group,Sham group,CLPgroup,CLP+Emodin group;LPS modeling mode: Blank group,NS group,LPS group,and LPS+Emodin group.Emodin pretreatment group were treated with emodin for 5 consecutive days before establishing the model of spesis.Animals were sacrificed at 12 h and 24 h after building,respectively.Moreover,the urine,abdominal aorta,feces in the intestine and the specimens of ileum was harvested for the detection of this experiment.The histopathological changes of intestinal mucosa and the ultrastructure of intestinal epithelial cells were observed by light microscopy and transmission electron microscopy.The vitality of DAO in blood was detected by enzyme-linked immunosorbent assay(ELISA).The L/M ratio in urine was determined by high performance liquid chromatography.The content of s Ig A in feces was detected by enzyme-linked immunosorbent assay(ELISA).The expression level of intestinal tight junction proteins claudin-3,zonula occludens(ZO)-1 and occludin were detected by immunohistochemistry,Western blotting and real-time PCR.Results 1.The intestinal mucosa of the sepsis model group showed different degrees of pathological changes at 12 h and 24 h.Under the light microscope,inflammatory cell infiltration,intestinal mucosal edema,intestinal epithelial cell shedding,villus tip destruction and mucosal erosion were observed.Electron microscopy showed that the tight junction structure of the cells was destroyed and the paracellular space was widened.The Chiu’s intestinal tissue injury score showed that the intestinal tissue injury score of the model group was significantly increased(P<0.01).However,the CLP modeling method was obvious for 24 hours,while the LPS modeling method was more obvious at 12 h.2.The DAO activity and the L/M ratio in urine were clinical indicators for detecting intestinal barrier permeability.The DAO activity in the blood and the L/M ratio in urine were significantly increased in the sepsis model group(P<0.05).CLP modeling is obvious at 24 h,while the LPS modeling method is more obvious at 12 h.3.SIg A is an important index for evaluating intestinal mucosal immunity.The s Ig A content in the stool of the sepsis model group showed a downward trend.The CLP modeling method was obvious at 24 h,while the LPS modeling method was more obvious at 12h(P<0.01).4.The protein expression and m RNA levels of Claudin-3,ZO-1 and Occludin were significantly decreased in the sepsis model group,and the Claudin-3 decreased more significantly(P<0.05).5.Compared with the CLP model group,the pathological damage of intestinal mucosa was significantly reduced after emodin intervention,and it was more obvious at 24h(P<0.05).In the 24 h emodin pretreatment group,the DAO activity in the blood and the L/M ratio in the urine decreased significantly(P<0.05),which were suggesting that emodin can inhibit the increase of intestinal mucosal permeability.The s Ig A content in the feces of the emodin pretreatment group were also increased at 24h(P<0.05).The expression of tight junction protein Claudin-3,ZO-1 and Occludin and gene levels were showed varying degrees of increase in the emodin pretreatment group(P<0.05).6.Compared with the LPS model group,the pathological damage of intestinal mucosa was significantly reduced after emodin intervention(P<0.01),and it was more obvious at 12 h.In the emodin pretreatment group at 12 h,the DAO activity in the blood and the L/M ratio in the urine decreased significantly(P<0.05),which were suggesting that emodin can inhibit the increase of intestinal mucosal permeability.The content of s Ig A in the feces of the emodin pretreatment group was increased at 12h(P<0.01).The expression of tight junction proteins Claudin-3,ZO-1 and Occludin in emodin pretreatment group were increased,which was more significant at 12h(P<0.05).Conclusion 1.The time nodes of CLP cecal ligation and intratracheal instillation of LPS to induce intestinal epithelial barrier damage in sepsis were not consistent.2.Emodin can significantly reduce the pathological damage of intestinal epithelial barrier in rats with sepsis,reduce intestinal barrier permeability,and enhance intestinal mucosal immunity.And the mechanism by which emodin maintains the integrity of the intestinal epithelial barrier of sepsis and protects the intestinal epithelial TJ barrier is associated with increased expression levels of the tight junction-associated proteins Claudin-3,ZO-1 and Occludin.