Protection Of Fecal Microbiota Transplantation On Dextran Sulfate Sodium-induced Ulcerative Colitis In Mice And Its Mechanism

AIM:To investigate the effects of fecal microbiota transplantation on dextran sulfate sodium-induced ulcerative colitis in mice and to explore its mechanism.METHODS:Sixty C57BL/6J mice were divided into six groups: group A(sterile water + saline group,10),group B(sterile water + UC fecal fluid group,10),group C(4%DSS + saline group,10),group D(4% DSS + normal fecal fluid group,10),group E(4% DSS + Si Liankang group,10),group F(4% DSS + UC fecal solution group,10).The general conditions of the mice in each group was observed.After the experiment,the colon length,spleen weight and DAI volume fraction were performed.The histological damage score was determined by HE staining.The myeloperoxidase activity of colon tissue was measured.RT-PCR was used to detect the abundance changes of Enterococcus and Lactobacillus in feces.Flow cytometry was used to detect the number of Th17 in whole blood of mice.The inflammation degree of IL-17,IL-23 and ROR?t in colon tissue was detected by immunohistochemistry.RESULTS:(1)Body weight,colon length,spleen weight and DAI score of mice in each group after model establishment: Compared with group A,the weight of group C was lost,colon length shortened,spleen weight increased and DAI score increased significantly,all statistically were significant(P<0.05 or P<0.01).Compared with group C,the above indicators of D,E group showed significant differences(P<0.05 or P<0.01).Compared with group C,group F has significant difference except DAI score.(P<0.05 or P<0.01).(2)Histological damage and scoring of colon:The histological damage of group B and C was higher than that group A(P<0.01).Group D and group E improved histological injury after treatment,group F was more serious than group C.Compared with the C group,the three groups were statistically significant(P<0.01).(3)Myeloperoxidase(MPO)activity in colon tissue:Compared with group A,MPO in group B and group C increased in different degrees(P<0.01).Compared with group C,MPO level in group D and group E decreased significantly(P<0.05),but group F increased significantly(P<0.05).(4)Abundance of Enterococcus faecalis and Lactobacillus in mice:Compared with group A,the abundance of enterococci in group C increased(P<0.05),the abundance of lactobacilli decreased(P<0.01).The abundance of enterococci was inhibited in treat with group E(P<0.05).The abundance of Lactobacillus in group D and group E was higher than that in group C(P<0.01).(5)Th17 cells in whole blood:The number of Th17 cells in group C was significantly higher than that in group A.In group D and group E,the number of Th17 cells was significantly lower.However,compared with group C,there was a statistical difference(P<0.01),but the Th17 cells in group F were lower than those in group C(P<0.05).(6)Levels of IL-23,IL-17 and ROR?t in colon tissue:Compared with group C,the expression levels of IL-17,IL-23 and ROR?t increased in group C(P<0.01).The three indexes in group D and group E decreased,which was statistically significant compared with group C(P<0.01).The expression levels of IL-17,IL-23 and ROR?t in group F were higher than those of group C(P<0.01).CONCLUSION:FMT alleviate the degree of UC inflammation induced by DSS in mice and improve the structure of intestinal flora.The mechanism may be related to the regulatoion of abnormal immunity of intestinal flora.Th17 cells and IL-23/IL-17 axis play an important role.