Effect Of Autotaxin-lysophosphatidic Acid Axis And Compound Sophorae Decoction On Th17 Cell Differentiation In Ulcerative Colitis

【Objective】Ulcerative colitis(UC)is a non-specific chronic colorectal mucosal inflammation disease which is easy to relapse,and the trend of the disease increased year by year,the pathogenesis is not yet fully understood.More and more studies have shown that the intestinal immune disorders play a major part in the pathogenesis,in which Th17 cells play an important role.Naive T cells companied with ROR-γt to differentiate into Th17 cells through the IL-6 / STAT3 pathway,then induced and maintained chronic inflammatory responses by secreting a major effector cytokine IL-17 A.The autotaxin-lysophosphatidic acid(ATX-LPA)axis is involved in the chronic inflammatory processes of many diseases.Studies have shown that ATX is also expressed in the colon tissues of chronic inflammatory bowel disease(IBD).However,the role and mechanism are not completely understood.The purpose of this study was to investigate whether ATX-LPA axis can play a role in the pathogenesis of chronic ulcerative colitis by regulating the differentiation of Th17 cells and whether Compound Sophorae decoction(CSD)can play a therapeutic role by interfering with ATX-LPA axis and the optimal dose of treatment,which will help elucidate the pathogenesis of chronic ulcerative colitis and provide new therapeutic research approaches.【Methods】Sixty SPF Balb/c male mice were randomly divided into 6 groups: normal group,model group,inhibitor group,low dose group of TCM,medium dose group of TCM and high dose group of TCM.After one week adaptive feeding,except for the normal group,the remaining groups were given 7 days administration of 2.5% DSS solution followed by other 7 days clean water for 3 cycles.The model group was intraperitoneally injected with1 mg of bithionol every other day,and the model group was injected intraperitoneally with the same volume of solution until the model was completed.At the beginning of the third cycle,mice of the low dose TCM group,middle dose TCM group,high dose TCM group began to give 0.4m L different concentrations of traditional Chinese medicine decoction daily gavage.Mice in the modeling process were observed spirit,diet,activity,stool traits and whether there is bloody stool daily,record the mouse body weight.Sacrificed mice and the spleens and mesenteric lymph nodes were removed to measure the proportion of Th17 cells in lymphocytes by flow cytometry.The length of the colon was measured and gently washed with PBS then weighed.Some tissues were fixed in 4% paraformaldehyde for HE staining to observe pathological changes of colon tissue;the rest of the tissue immediately placed at-80 ℃ for other tests.The ATX and MAd CAM-1 proteins in colonic tissues were measured using western blot.The expression of ATX,MAd CAM-1,LPAR,IL-6,STAT3,ROR-γt,IL-17 A and IL-21 m RNA in colonic tissues were detected by rt PCR.【Results】After DSS-induced modeling,mice had poor activity,loose stools even blood stools,and the body weight decreased significantly.Compared with normal group,the proportion of Th17 cells in the spleen and mesenteric lymph nodes in the model group was obviously higher than that in the normal group,so were they with the expression of ATX,MAd CAM-1 proteins in colon.And the expression of ATX,MAd CAM-1,LPAR,IL-6,STAT3,ROR-γt,IL-17 A and IL-21 also increased significantly in the colon tissues(P<0.05).Compared with the inhibitor group,the proportion of Th17 cells and the expression of these above indicators decreased,the difference was statistically significant(P <0.05).Compared with the model group,the proportion of Th17 cells in the low-dose,medium-dose and high-dose groups of TCM and the expression of the above indexes all showed a decreasing trend.The middle-dose group of TCM showed the highest decrease in each index compared with model group,the difference was statistically significant(P<0.05).while compared with inhibitor group,low-dose group and high-dose group of TCM,the differences were not complete significant.【Conclusion】1.ATX-LPA axis can participate in the pathogenesis of DSS-induced chronic ulcerative colitis,aggravating intestinal inflammation and intestinal mucosal damage;2.ATX-LPA axis may participate in the pathogenesis of chronic ulcerative colitis by promoting Th17 cell differentiation;3.Inhibition of ATX-LPA axis can play a therapeutic role and relieve intestinal inflammation by reducing Th17 cell differentiation,the CSD may also play an effect by inhibiting the axis,and middle dose was the best choice.