Objective:To observe the effects of acupuncture and moxibustion on interleukin(IL)-9/IL-9 receptor(IL-9R)in the colon tissue of rats with ulcerative colitis(UC)and investigate the protective mechanism of acupuncture and moxibustion on the intestinal mucosal barrier in UC rats. Methods:Male Sprague-Dawley rats were randomly divided into a normal control(NC)group and a modeling group.UC models were prepared by giving 4%dextran sulfate sodium(DSS)water for 7 d.After the successful construction of the UC rat model,the modeling group was randomly divided into a UC group,a herb-insulated moxibustion(HM)group,and an electroacupuncture(EA)group.HM and EA interventions at bilateral Tianshu(ST25)were performed once a day for 7 d.Hematoxylin-eosin(HE)staining was used to observe the histopathological changes in the colon.The serum concentrations of IL-9,IL-6,IL-1β,and hemoglobin-H(HbH)were determined by enzyme-linked immunosorbent assay.The protein expression levels of IL-9,IL-9R,claudin-2,zonula occludens-1(ZO-1),and occludin in the colon tissue were measured by Western blotting or immuno-histochemistry.Immunofluorescence was used to detect the co-expression of PU.1 and CD4 with the IL-9 protein. Results:Compared with the NC group,the colon tissue of UC rats was severely damaged and ulcerated with congestion and edema,and the colonic histopathological score increased significantly(P<0.01).The serum HbH concentration decreased significantly(P<0.01),while the serum concentrations of IL-9,IL-6,and IL-1β increased(P<0.01).The protein expression of colonic ZO-1 and occludin decreased significantly(P<0.01),while the protein expression of colonic IL-9 and IL-9R increased(P<0.05).The positive co-expression levels of IL-9/PU.1 and IL-9/CD4 increased in the colon tissue(P<0.05).Compared with the UC group,the colonic mucosal structures were gradually repaired in both HM group and EA group,and healed ulcers could be observed,the colonic histopathological score decreased significantly(P<0.05).The serum concentration of HbH increased(P<0.01),while the serum concentrations of IL-9,IL-6,and IL-1β decreased(P<0.05).The protein expression levels of ZO-1 and occludin increased(P<0.05),while the protein expression levels of IL-9 and IL-9R decreased(P<0.01).The positive co-expression levels of IL-9/PU.1 and IL-9/CD4 decreased in the colon tissue(P<0.05). Conclusion:Both HM and EA can inhibit the protein expression levels of IL-9 and IL-9R in the UC colon by regulating the transcription factor PU.1,promote the repair of intestinal mucosal barrier,and down-regulate protein contents of proinflammatory factors IL-9,IL-6,and IL-1β in the serum,which may be one of the key mechanisms of acupuncture and moxibustion in reducing the inflammation of UC colonic mucosa and protecting the intestinal mucosal barrier.