Objective,2,To observe the expression of pregnane X receptor （PXR）， nuclear factor κB p65（NF-κBp65）， interleukin -10（IL-10）， tumor necrosis factor -α（TNF-α） and transforming growth factor -β（TGF-β） in colon tissue of rats with ulcerative colitis（UC）of large intestine damp-heat type caused by retention enema with Yuxian Formula.,Methods,2,53 rats were randomly divided into 6 groups，that is blank control group，model group，positive control group，low dose treatment group， medium dose treatment groupand high dose treatment group with，8 in blank control groupand 9 in other groups. Except the blank control group，the other groups were established ulcerative colitis models.After successful modeling， the drug was given. The positive control group was given 0.02 g/mL sulfasalazine （SASP） 3 mL enema， and the low， medium and high dosage groups were given 0.09 g/mL， 0.18 g/mL and 0.36 g/mL YuAmaran Decoction 3 mL enema respectively， while the blank control group and model group were given the same volume of normal saline enema，once a day for 14 days.After the experiment finished，the colon tissue was collected，the histological injury score and colonic mucosal injury score of each group were compared. The expressions of PXR protein and NF-κB p65 protein in colon tissue were detected by Western blotting， and the levels of IL-10， TNF-α and TGF-β in colon tissue were detected by ELISA.,Results,2,The colon mucosa in blank control group was normal.In the model group， the colonic mucosa was seriously eroded and there were large superficial ulcers. Compared with the model group， the number and area of colonic ulcers in each treatment group were reduced， and the mucosal injury was alleviated.Compared with the blank control group， the scores of colonic mucosal injury， histological injury， NF-κB p65 protein expression， TNF-α and TGF-β levels in the model group were higher， while the expressions of PXR protein and IL-10 in the colon tissue were lower（,P,<,0.01）.Compared with the model group， the scores above， the expression of NF-κB p65 protein， the levels of TNF-α， TGF-β， TNF-α and TGF-β in each treatment group were all low， while the expression of PXR protein and the level of IL-10 were high（,P,<,0.05，,P,<,0.01）. The scores above and the expression of NF-κB p65 protein in the high-dose group were lower than those in the low-dose and middle-dose groups， while the expression of PXR protein and the level of IL-10 were higher than those in the low-dose and middle-dose groups （,P,<,0.05，,P,<,0.01）.There was no significant difference compared with the positive control group of SASP group（,P,>,0.05）.,Conclusion,2,Yuxian Formula retention enema can repair intestinal mucosal injury in UC rats with damp-heat type of large intestine， and regulate PXR/NF-κB signaling pathway and inflammatory factors.