AhR Reduces IPEC-J2 Cell Inflammation And Plays The Role In Diarrheal Enteritis Of Rabbitis

Diarrhea is the main cause of piglet death.Effective treatment of piglet diarrhea is a strong guarantee for the healthy development of pig breeding industry.Aromatic hydrocarbon receptors(aryl hydrocarbon receptor,AhR)play an important role in the occurrence and development of inflammatory diseases,but there are few studies on the relationship between AhR and animal diarrhea.Diarrhea can cause intestinal inflammation,damage of intestinal mucosal barrier and abnormal expression of NHE3/AQP4.Chloride channel blocker(CF)has become a new method for the treatment of secretory diarrhea.In this paper,lipopolysaccharide(lipopolysac-charides,LPS)was used to induce inflammation in porcine small intestinal epithelial cell IPEC-J2.Different agonists activated AhR to evaluate the role of AhR in oxidative damage and regulation of NHE3/AQP4 expression in IPEC-J2 cells.Combined with the treatment of anti-inflammatory substances(HO-1 and EH),to clarify the molecular mechanism of AhR activation inhibiting inflammation.Finally,CF was used to treat diarrhea rabbits,based on inflammatory factors,intestinal mucosal morphology and AhR signal changes to clarify the role of AhR in diarrheal enteritis.The result is as follows:Construction of an IPEC-J2 cell model of inflammation: The viability of IPEC-J2 cells was detected by CCK8 assay.The results showed that only 15 μg/m L LPS could significantly decrease the viability of IPEC-J2 cells treated with different concentrations of LPS for 6 h,3~15 μg/m L LPS for 12 h and 24 h,and 5 μg/m L LPS for 12 h.The results of RT-PCR showed that the expression of IL-1α m RNA was significantly up-regulated by 3 μg/m L LPS for 12 h,but there was no significant difference in the expression of IL-6 and TNF-α m RNA,while the expression of IL-1α,IL-6 and TNF-α m RNA was significantly up-regulated by 5 μg/m L LPS for 12 h.Based on the above results,5 μg/m L LPS was selected to treat IPEC-J2 cells for 12 h to establish an inflammatory cell model.Activated AhR reduces oxidative damage in IPEC-J2 cells and increases AQP4 and NHE3 expression: Compared with CT group,AhR/CYP1A1 signal was suppressed and the expression of AQP4 and NHE3 was decreased in inflammatory IPEC-J2 cells.After AhR was activated by ligands FICZ and PY109,the expression and content of IL-1α,IL-6 and TNF-α m RNA decreased,the content of MDA in cell supernatant decreased,the content of SOD and GSH-Px increased,and the expression of AQP4 and NHE3 increased.It is suggested that activated AhR can alleviate the oxidative damage induced by LPS in IPEC-J2 cells and participate in water and ion transport.Anti-inflammatory substance activates the effect of AhR to inhibit inflammation:Compared with CT group,anti-inflammatory substances promoted the expression of AhR/CYP1A1 m RNA and protein,while anti-inflammatory substances significantly decreased the expression and content of IL-1α,IL-6 and TNF-α m RNA in inflammatory IPEC-J2 cells.At the same time,it decreased the content of MDA in the supernatant of inflammatory cells,and increased the content of SOD and GSH-Px.It is suggested that HO-1 and Herba Euphorbiae can activate AhR and inhibit cell inflammation.Role of AhR in diarrheal enteritis in rabbits: Compared with CT group,the body weight of diarrhea rabbits decreased,DAI score increased,cecum wall was thin with bleeding necrosis,colon atrophy,intestinal villi atrophy and rupture,inflammatory cell infiltration,plasma IL-1α,TNF-α content increased,indicating that diarrhea caused intestinal inflammation.At the same time,the expression of AQP4 and NHE3 in intestinal tissue of diarrhea rabbits was down-regulated,and AhR/CYP1A1 signal was inhibited.After CF treatment,the weight of rabbits increased,DAI score decreased,intestinal inflammation and intestinal mucosal barrier improved,the contents of IL-1α and TNF-α in plasma decreased,and the expression of AQP4,NHE3 and AhR/CYP1A1 m RNA increased.It is suggested that diarrhea enteritis inhibits AhR/CYP1A1 signal,and CF can activate AhR/CYP1A1 signal to inhibit intestinal inflammation and regulate cellular water and ion transport.In conclusion,AhR activation can alleviate the oxidative damage of porcine intestinal epithelial cells and participate in water and ion transport;anti-inflammatory substances can activate AhR and inhibit cell inflammation;diarrhea enteritis inhibits AhR/CYP1A1 signal,CF can activate AhR/CYP1A1 signal to inhibit intestinal inflammation,regulate cell water and ion transport,and relieve secretory diarrhea.