Study On The Effect Of Schistosoma Japonicum Infection In CD4⁺CD45RB^highT Cell Induced Inflammatory Bowel Disease

ObjectiveThis study aimed at constructing the CD4⁺CD45RB^highT cell induced colitismouse model, studying the effect of Schistosoma japonicum infection on thepathological changes and mesenteric lymph node and spleen cell cytokinesecretion in this colitis mouse model, and preliminary discussing themechanism of Helminth-SCID-T cell model.MethodsCD4⁺CD45RB^highT cells, which were from BALB/c mice’s spleen peripherallymph node and mesenteric lymph node, were transferred into the samebackground SCID mice（1.2¹.4×10⁶/mouse） by intraperitoneal injection. Then,the SCID mice were divided into two groups at random. Group â… was IBDgroup, group â…¡ was concurrent infection-IBD group which was infected with22±2Schistosoma japonicum cercarie through skin of abdomen. Everydayobservation the changes of weight, defecate, hair, etc. At2,4,6and8weeksafter cell transfer, mice were sacrificed to evaluate the colonic histologicalchanges; removing spleen and the mesenteric lymph nodes, meshingorganization, preparing cell suspension. By ELISA, and flow cytometrydetecting IFN-γ, IL-4expression of spleen and mesenteric lymph nodes.Results General situation：CD4⁺CD45RB^highT cell-mediated colitis in SCID mice wasconstructed successfully. SCID mice appeared weight decrease that began1to2weeks after cell transfer. SCID mice appeared anorexia, lazy, arch,vertical hair, soft stool, diarrhea, prolapse, et al.Pathological results（HE）: In group â… , the colon pathology score at8weeks was significantly higher than4weeks. At4weeks, there weresignificant differences between the two groups（P<0.05）. The colon pathologyscore of group â…¡was significantly higher than group â… , average score was5.8±0.8scores and2.0±0.6scores. At8weeks, there were significantdifferences between the two groups（P<0.05）. The colon pathology score ofgroup â…¡was significantly lower than group â… , average score was2.2±0.8scores and5.5±0.5scores.Flow cytometry results:4Weeks: Group â…¡, IFN-γ（Th1） in the ratio:43.48±6.24（%）; group â… , IFN-γ（Th1） ratio was:28.37±3.66（%）, the difference wasstatistically significant（P<0.05）. Group â…¡, IL-4（Th2） ratio was:3.15±0.83（%）;group â… , IL-4（Th2） ratio was:10.88±1.25（%）, the difference was statisticallysignificant （P<0.05）. Group â…¡, Th1/Th2ratio was:14.16±2.23; group â… ,Th1/Th2ratio was:2.62±0.33, the difference was statistically significant（P<0.05）.8Weeks: Group â…¡, IFN-γ（Th1） in the ratio:20.92±4.02（%）; groupâ… , IFN-γ（Th1） ratio was:40.90±2.79（%）, the difference was statisticallysignificant （P<0.05）. Group â…¡, IL-4（Th2） ratio was:1.78±0.77（%）; group â… ,IL-4（Th2） ratio was:2.62±0.23（%）, the difference was not statisticallysignificant （P>0.05）. Group â…¡, Th1/Th2ratio was:12.81±4.30; group â… ,Th1/Th2ratio was:15.63±0.99, the difference was not statistically significant（P>0.05）.ELISA test results:4Weeks:â‘ IFN-γ level of splenocytes in group â…¡:（168.53±12.01）pg/ml, group Ⅰ（:114.18±41.83）pg/ml, P<0.05. IL-4level ofsplenocytes group â…¡:（65.46±9.85）pg/ml, group â… :（130.06±18.56）pg/ml,P<0.05.â‘¡IFN-γ level of MLN cells in group â…¡:（177.58±43.15）pg/ml, group â… :（105.49±35.40）pg/ml, P<0.05. IL-4level of MLN cells group â…¡:（70.01±2.96）pg/ml, group â… :（172.33±37.39）pg/ml, P<0.05.8weeks:â‘ IFN-γ level of splenocytes in group â…¡:（104.89±25.13）pg/ml,group â… :（213.58±38.70）pg/ml, P<0.05. IL-4level of splenocytes group â…¡:（129.71±30.63）pg/ml, group â… :（86.78±24.96）pg/ml, P<0.05.â‘¡IFN-γ levelof MLN cells in group â…¡:（94.09±14.82）pg/ml, group Ⅰ（:193.05±49.70）pg/ml,P<0.05. IL-4level of MLN cells group â…¡:（128.18±32.87）pg/ml, group â… :（107.34±21.21）pg/ml, P<0.05.ConclusionsCD4⁺CD45RB^highT cells transfer into SCID mice can make T cell-inducedanimal model of IBD. The mice that were infected by Schistosoma japonicumincreased pathological damage in the early stage of inflammation, while itinhibited colitis in the late stage. It need to be cautious when using worms totreat IBD.