The Significance Of Change Of Th17Cells And Treg Cells In Mouse Model With Experimental Autoimmune Myocarditis

Objective:To investigate the alteration of specific transcription factorits(RORγt, Foxp3) ofTh17cells and Treg cells,together with their related cytokines(IL-17, TGF-β)indifferent stages of murine experimental autoimmune myocarditis,and then toinvestigate their role in EAM.Methods:Balb/C mice were immunized with porcine cardiac myosin covered bycomplete freund’s adjuvant (CFA) to establish animal model of experimentalautoimmune myocarditis. Normal control group was immunized with PBS and CFAwithout porcine cardiac myosin. And grouped in the following way, every groupcontains six mice. All mice were sacrificed in the specified time point, and return theheart specimens.The myocardial tissues were stained with hematoxylin&eosin todetermine the level of myocardial inflammation and the pathological scores, RORγt,Foxp3, IL-17and TGF-β mRNA in the myocardium of mice were assessed bysemi-RT-PCR. Immuno-histochemicalstaining detection was used to position andqualitative analysis the expression of IL-17and Foxp3. IL-17and TGF-β protein fromblood serum were determined by ELISA.Grouping one:EAM group and normalcontrol group were randomly divided into three subgroups in accordance with7d,21d,56d; Grouping two:then EAM group were randomly into three groups:IL-17mAbgroup, Isotype control group, PBS group. Followed by injection, the mice wereinjected intraperitoneally with100μg/0.1ml IL-17monoclonal antibody (IL-17mAbgroup), or100μg/0.1ml immunoglobulin(Ig)G2AAb(isotype group),or0.1mlPBS(PBS group)on day0,1and2day. Results:1. Myocardial tissue pathological changes: EAM mice7d myocardial cell wereswelling, large numbers of inflammatory cells infiltrated all epicardial and myocardialinterstitial in21d, muscle fiber arrangement were disorder, with myocardial necrosisarea, Inflammatory cells significantly decreased in56d, appear more fiberhyperplasia. Compared with the control, pathological scores of mice in EAM group ofeach time point are elevated (P <0.05). Myocardial cells in normal control grouparranged in uniform. They had no inflammatory cells infiltration and myocardial cellnecrosis. The infiltrates cells decreased significantly in IL-17mAb group, comparedwith isotype control group and PBS group, and was significantly reduced (P <0.01),but was still higher than normal group. With the comparison between isotype controlgroup and PBS group has no statistical significance (P>0.05), were significantlyhigher than normal control group (P <0.01).2. The expression of IL-17and Foxp3in ventricular tissue: The expression ofIL-17and Foxp3protein was little on EAM7d, peaked on21d, then decreased on56d,but still higher than normal mice (P<0.01). No statistical difference were seen whencompared the expression of IL-17and Foxp3among control subgroups (P>0.05). Theprotein level were significantly reduced in IL-17mAb group, lower than those inisotype control group and PBS group, higher than the normal group(P <0.01). IL-17and Foxp3protein expression of isotype control group and PBS group weresignificantly increased, but had no difference between the two groups (P>0.05).3. The expression of RORγt, Foxp3, IL-17and TGF-β mRNA in ventriculartissue: The mRNA of RORγt, Foxp3, IL-17and TGF-β in EAM subgroup were higherthan those of controls (P<0.05), but had no significant difference between7d and56din EAM group (P>0.05). The peak period was at EAM21d. The level in IL-17mAbgroup, isotype control group and PBS group higher than the control group (P <0.01).But there was no difference between them (P>0.05).4. The level of TGF-β and IL-17in serum The level of sera TGF-β and IL-17in21d and56d subgroup in EAM were markedly higher than that in controlgroup(P<0.05), both expression in21d were markedly higher than those in56d and7d subgroups (P<0.01).But there was no significantly difference among controlsubgroups (P>0.05). IL-17mAb group was obviously lower than isotype control groupand PBS group, higher than control group. IL-17and TGF-β content in the isotypecontrol group and PBS group were significantly higher than the control group,but hadno difference between the two groups.Conclusions:1. Repetitively immunized with porcine cardiac myosin was capable of inducingexperimental autoimmune myocarditis.2. The imbalance of Th17/Treg may promote the development of cardiac muscleinflammation.3. Anti-IL-17treatment can obviously relieve the myocardial inflammation.