TLR2-deficient Mice Alleviate Experimental Enteritis By Down-regulating The Production Of IL-17~+T Cells As Well As Reducing The Secretion Of Inflammatory Cytokines IL-6 And IL-23

Objective:By observing the disease progression of TLR2-deficient mice and wild-type mice in experimental enteritis,detecting the number of relevant immune cells and the secretion of inflammatory factors,and related histopathological changes,the Toll-like receptor 2 was explored experimentally.The role of enteritis provides new support for TLR2 as a target for disease treatment.Method:1.Induction of mouse experimental enteritis model:The first day of modeling was recorded as the first day,and mice were fed 3.5%DSS solution from the first day to prevent drug decline on days 3 and 5.Fresh 3.5%DSS solution was replaced,water was changed on day 7,mice were sacrificed on day 8 and samples were collected for subsequent testing.Control mice were given the same volume of water daily.The mice were weighed at the same time every day during the modeling,and the hair,activity state,and the like of the mice were observed and recorded.2.Take the colon tissue of mice,measure the length,and perform pathological scoring after HE staining.Flow cytometry is used to detect IL-17~+T cells,Th1 cells and Th2 cells in mesenteric lymph nodes and intestinal lamina propria mononuclear cells.The number of Treg cells.3.Extraction of colon tissue RNA detects the expression of disease-associated inflammatory factors and cytokines involved in the induction of IL-17~+T cell production at the molecular level.4.Flow cytometry was used to detect the ratio of macrophage and dendritic cells in the mesenteric lymph nodes,peritoneal lavage fluid and related cytokine secretion.5.The mouse intestinal epithelial cells were cultured and the supernatant was collected,and the secretion of related cytokines in the supernatant was detected by ELISA.Result:1.After the successful construction of the enteritis model,it can be observed that the TLR2-deficient mice develop later than the wild mice,and the weight loss is lower than that of the wild mice.In the late stage of the mice,the wild mouse fur lost its luster and acted slowly,while the TLR2-deficient mice were in good condition.2.Compared with the control group,the colon length of TLR2-deficient mice was longer than that of wild mice,and the damage of tissue structure after HE staining was lighter than that of wild mice.After flow cytometry,the ratio of Th17 cells, Th1 cells,IL-17~+??T cells to CD4~+T cells in TLR2-deficient mice was lower than that in wild mice,but there was no significant difference in Th2 cells and Treg cells.3.The expression levels of IL-17,TNF-?,IL-1?,CCR6 and CCL20 in the colon tissue of TLR2-deficient mice were lower than those in wild mice,but there was no significant difference in the expression of IL-10.The expression levels of IL-6 and IL-23 in cytokines capable of inducing IL-17~+T cells were lower than those in wild mice,and there was no significant difference in the expression level of TGF-?.4.In the mesenteric lymph nodes of mice,the proportion of macrophages in TLR2-deficient mice and the proportion of macrophages secreting IL-6 and IL-23 were lower than those in wild mice;the proportion of dendritic cells was lower than that in wild mice.However,there was no significant difference in the proportion of dendritic cells secreting IL-6 and IL-23.5.After modeling,the concentration of IL-6 in the intestinal epithelial culture supernatant extracted from TLR2-deficient mice was lower than that in wild mice.Conclusion:In the experimental enteritis model,the loss of Toll-like receptor 2 on macrophages and intestinal epithelial cells can reduce the secretion of IL-6 and IL-23 and reduce the differentiation of IL-17~+T cells to alleviate enteritis.