Expression And Correlation Of IL-33 In Ulcerative Colitis

BackgroundInflammatory bowel disease(IBD)is a chronic and relapsing disease of the intestine which mainly includes ulcerative colitis(UC)and Crohn's disease(CD).IBD is prevailing in western developed countries.In recent years,the incidence of IBD in China has been increasing with the change of people's lifestyle and diet,the enhancement of medical workers' consciousness of IBD and the improvement of medical technology.IBD can not only cause abdominal pain,diarrhea,ileus and other digestive system manifestations,but cause extraintestinal symptoms,such as arthritis,uveitis,and thromboembolic diseases.It can cause intestinal fibrosis,stricture,perforation,cancer and other serious complications if not properly managed.IBD significantly reduces the life quality of patients,causing great distress to patients and their families.At present,the pathogenesis of IBD is still under exploration.It is generally believed to be the result of the combined effects of immunity,environment,genetics and intestinal flora.In addition to the classical treatments,such as amino salicylic acid and immunosuppressant,the use of biological agents,granulocyte and monocyte adsorptive apheresis,and fecal microbiota transplantation have also been gradually applied in clinical practice in recent years.However,there are still some patients with poor disease control.It is imperative to develop a new measure.Interleukin-33(IL-33),a newly discovered interleukin-1(IL-1)family molecule,plays an important role in innate and adaptive immunity.Several studies have shown that the abnormal expression of IL-33 in a variety of autoimmune diseases and chronic diseases.It may also be related to the incidence of UC.Therefore,studying the expression of IL-33 in UC is helpful to elucidate its pathogenesis and find new potential therapeutic targets.ObjectiveTo compare the serum levels of IL-33 in UC and its clinical significance,so as to better explore the pathogenesis of UC and seek potential therapeutic targets.MethodsA total of 60 healthy controls and 85 UC patients from May 2018 to May 2019 of The First Affiliated Hospital of Zhengzhou University were enrolled,and the serum IL-33 was detected by enzyme linked immunosorbent assay(Elisa).C57BL/6J male mice,8-10 weeks old,were randomly divided into 2 groups with 6 mice in each group,the control group and the DSS-induced model group.Distilled water was fed to the control group,and the DSS-induced model group received 3%DSS solution,other breeding conditions were the same.The mental state,body weight and stool of the mice were recorded everyday and then evaluated disease activity index(DAI).The mice were killed on the eighth day.The macroscopical and histopathological changes of colon were observed.The expression of serum IL-33 was measured by Elisa and the expression of IL-33 mRNA in colon tissue was evaluated by real time quantitative PCR(qRT-PCR).Results(1)The level of IL-33 in the serum of UC patients was significantly higher than that in the control group,and it was related to the severity of illness.There was significant difference among the mild UC,moderate UC and severe UC(P<0.05).(2)Mice in the control group were generally in good condition,with slight weight gain;mice in the DSS group had decreased activity,decreased hair color gloss,and decreased food intake;on the 3rd to 7th day,there were gradually shapeless stool,positive fecal occult blood test,and bloody stool.The length of colon was shorter and mucosa was congestive and edema in the DSS group.Besides,the histopathology showed that the epithelial mucosal integrity of mice in the DSS group was destroyed,a large number of inflammatory cells were infiltrated,and the crysts were reduced or even disappeared,which conformed to the pathological changes of UC.(3)The expression of serum IL-33 in DSS group was significantly higher compared with the normal control group,and the expression of IL-33mRNA in the colon tissue was substantially higher than the control group(P<0.05).Conclusion(1)IL-33 in the serum of UC patients increases and tends to increase with the severity of disease,it may be involved in UC.(2)The expression of IL-33 in DSS-induced UC mice models is significantly higher compared with the control group,which further verifies that IL-33 expression is abnormal in UC,and IL-33 may play a role in the occurrence and development of UC.Its specific mechanism needs further study.