Study On The Effect And Mechanism Of SLC5A8 Gene In Mice With Acute Ulcerative Colitis

Objective:Ulcerative colitis（UC）is one of the major type of inflammatory bowel disease（IBD）.The occurrence of UC is the result of many factors,but the specific mechanism is not clear.Previous studies have shown that SLC5A8 gene is highly expressed in normal colonic epithelial cells,which encodes Na⁺-coupled monocarboxylate transporter.Considering that SLC5A8 may have effect in the pathogenesis of UC,the test used the dextran sodium sulfate induce ulcerative colitis to find the effect and mechanism of SLC5A8.Judging the effect of SLC5A8 in acute ulcerative colitis directly by evaluating the clinical manifestations and body weight of mice in the early stage.Judging the role of SLC5A8 in the severity of UC by comparing the colon length and pathology in the later stage.At the same time,the effect and mechanism of SLC5A8 gene deletion in UC were explored by detecting serum cytokines and T lymphocyte subsets.Methods:（1）Grouping:Choosing 16 wild-type（WT）mice and 16 SLC5A8^-/-（KO）mice with gene background of C57BL/6,female,aged from 10 to 12 weeks and weighing from 22g to26g.Divided them into two groups WT and KO.Each group was further divided into two groupsa nd marked:（1）WT-DSS、（2）WT、（3）KO-DSS、（4）KO（2）Establishment murine colitis model:The mice in（1）（3）were given 2.5%DSS solution to induce murine colitis model,（2）（4）feeded by normal water.If rectal bleeding,loose stool and weight loss occur in mice,the modeling is successful;（3）Evaluation of the degree of inflammation:During the modeling period,the weight of the mice was measured daily,the fecal properties were observed,and the disease activity index was scored;after DSS intervention,the mice were killed,the colon length was compared,and the degree of inflammation was evaluated by observing the colon he pathological section;（4）Explore the changes of cell and molecular biology:the levels of inflammatory cytokines in serum were measured by ELISA,and the changes of T lymphocyte subsets in colon tissue,mesenteric lymph nodes and peripheral blood were measured by flow cytometry.Results:（1）The body weight of KO mice intervened by DSS was significantly lower than that of WT mice,and there was a statistical difference from the 4th day of modeling（P=0.008）.The disease activity index score also showed a statistical difference from the 4th day（P=0.0055）,KO mice have higher score.（2）The colon of KO mice treated with DSS was shortened more significantly than that of WT mice（P=0.0004）.Pathological examination showed that the colon mucosa of KO mice was obviously disordered and disappeared,and a large number of neutrophils were infiltrated,ulcerated or eroded.（3）Compared with WT mice,the level of IL-10 in KO mice intervened by DSS increased,but it was not as high as that in WT mice（P=0.0385）.The content of TGF-β1 in KO mice was lower than WT mice（P=0.008）.（4）Compared with WT mice,the proportion of CD4⁺T cells in blood of KO mice intervened by DSS had no difference,and the proportion of CD4⁺T cells in colon and mesenteric lymph nodes decreased（P<0.0001）;the proportion of CD4⁺/CD8⁺T cells in colon tissue and mesenteric lymph nodes decreased（P=0.0071,P=0.0102）.Conclusions:（1）SLC5A8 gene plays an inhibitory role in the progression of acute ulcerative colitis;（2）SLC5A8 gene plays an important role in the progression of UC by adjusting the content of IL-10 and TGF-β1;（3）SLC5A8 gene regulates the body’s immunity by mainly regulating the proportion of CD4⁺T cells in colon and mesenteric lymph nodes,and then affects the progress of UC.