Effect Of LBP On The Balance Of Th1/Th2 And Th17/Treg Cells In DSS Induced Colitis Mice

Objective: There is strong evidence to support that deregulated immune response to commensal bacteria drives UC,and CD4+T determine the direction and degree of UC within a series of deregulated immune response.Our previous research found that LBP could ameliorate clinical performance of DSS-induced chronic ulcerative colitis in mice,but the pathogenesis mechanism is still unclear.So we consider from the immune balance of Th1/Th2 and Th17/Treg to gain an insight of the pathogenesis mechanism of UC,and confirm the mechanism of LBP ameliorate clinical performance of DSS-induced chronic ulcerative colitis in mice.Methods: 1.A total of 75 C57BL/6 male mice were randomly divided into five groups(n=15,each group): normal control,DSS group(treated with 1.5% DSS 7 days and then normal water 7 days,repeat this cycle half past 3 times,totally 49 days),LBP groups,Mesalazine groups,Combined treatment group.Experimental colitis was induced as mentioned above,mice were treated from the second day;2.Throughout the experimental period multiple clinical parameters were measured.The body weight,stool consistency,and the occuilt blood in stool or at the anus were recorded daily.The disease activity index(DAI)was a mean score of the five parameters.Colon tissue was analyzed macroscopically,and the indexes of spleen was measured;3.Detection CD4+T cell surface expression and cell numbers: Mice were sacrificed on the 50 th days,peripheral blood,colon and spleen were collected to prepare mononuclear cells,CD4+T cell surface expression and cell numbers were defected by the flow cytometry.We define the CD4+IFN-γ+ T cells as Th1 cells,CD4+IL-4+ T cells as Th2 cells,CD4+IL-17+ T cells as Th17 cells,and CD4+CD25+Foxp3+ T cells as Treg cells.Results: 1.Model verification: two days after estabilishing the DSS-indced model,all miceshad loose stools,and compaired with control group showed slow response,lack of movement,messy hair,poor appetite,little drinking-water and loose weight.The DSS-indced mices colon shorten with varying degrees(6.13 ± 0.37 VS 8.48 ± 0.45,p=0.005),the macroscopic feature showed extensive mucosal injury throughout the colon(score is 4.22±0.95),and the indexes of spleen with DSS-indced mice model were much higher then the control group(13.32±1.78 VS7.48±0.57,p=0.001),revealed the DSS-indced mice was success to make chronic UC model;2.AS to the CD4+T cell surface expression and cell numbers between chronic UC model and control groups,compaired with control groups,the chronic UC model mices shown a down regulate of Th1 cells(8.62±1.52 VS 15.34±1.92,p=0.002),up regulate of Th2 cells(8.25±1.39 VS 1.36±1.08,p=0.002),and so as to the Th17 and Treg cells.All of them have a significance difference(p<0.05);3.Detect the CD4+T cell surface expression and cell numbers of all the five groups:(1)In general,different tissues with different experssion of sub-cells,the colon is the highest and peripheral blood is the lowest.(2)Compared with the chronic UC model mice,the Intervention groups with a high experssion of Th1 cells,and low experssion of Th2,Th17 and Treg cells.(3)The performance of Combined treatment groups was better than LBP groups and Mesalazine groups.(4)Compared with the chronic UC model mice,the Intervention groups with a high rato of Th1/Th2(p<0.05).Conclusion: 1.Treated with 1.5% DSS 7 days and then normal water 7 days,repeat this cycle half past 3 times could to success to make chronic UC model;2.DSS induced chronic UC by influence the immune balance of Th1/Th2 and Th17/Treg;2.LBP may facilitate immune balance of Th1/Th2 to ameliorate clinical performance of DSS-induced chronic UC in mice.