IL-6单克隆抗体对自身免疫性心肌炎的保护作用及其机制

目的：观察白介素-6（interleukin，IL-6）单克隆抗体（IL-6 mAb）治疗Lewis大鼠自身免疫心肌炎（EAM）的疗效。探讨IL-6与辅助性T细胞17（Th17）、调节性T细胞（Treg）在EAM发病中的机制。方法：将34只8-10周龄Lewis大鼠随机分为正常对照组（n=6），EAM组（n=12），IL-6mAb干预组（n=16）。对EAM组和干预组注射心肌肌凝蛋白，干预组于免疫注射后第1、7至第20天腹腔注射IL-6 mAb1nlg，分别于急性峰值期（第21天）、慢性持续期（第84天）取材，观察心肌炎症浸润、纤维化、细胞凋亡以判断IL-6mAb疗效。检测脾脏TH17、Treg细胞数量和功能，比较各组血清中IL-6、IL-10、IL-17和转化生长因子．β（TGF-β）的浓度，实时定量PCR测定外周血STAT3、RORγt、Foxp3mRNA水平，对EAM源性脾细胞进行体外IL-6mAb刺激，并用ELISA法测定IL-10、IL-17和TGF-β的浓度。结果：炎症积分、纤维化积分、凋亡指数IL-6mAb干预组较EAM组明显下降（P〈0．01）。急性峰值期（21d组）EAM组TH17和Treg细胞数量上调，干预组则受明显抑制（P〈0．01）；21d干预组血清IL-6、IL-10、IL-17和TGF-β的浓度较EAM组明显下降（P〈0．01）；21d干预组外周血STAT3、RORγt、Foxp3mRNA水平下降（P〈0．01）；体外IL-6mAb刺激EAM源性脾细胞，IL-10、IL-17和TGF-β表达明显增加。结论：IL6mAb对EAM有明显的保护作用，IL6mAb通过抑制Th17、Treg细胞的数量和功能，实现对EAM的保护作用。

The protective role of interleukin-6 monoclonal antibody on experimental autoimmune myocarditis and its mechanism

Objective： To investigate the therapeutic effect of IL-6 mAb on experimental autoimmune myocarditis （EAM） in rats, and search the mechanism of the role of IL-6, helper T cells 17 （Thl7） and regulative T cells （Treg） in EAM pathogenesis. Methods： Thirty-four Lewis rats were divided into three groups randomly, i.e. control group （ n = 6）, EAM group （ n = 12）, and IL-6 mAb intervention group （ n = 16）. Rats in EAM group and IL-6 mAb intervention group were injected intracutaneously with myosin to establish EAM model. Rats in IL- 6 mAb intervention group were injected intraperitoneally with 1 mg IL-6 mAb on 1st, 7th to 20th day after cardiac myosin immune injection. My ocardial inflammation was examined by HE stain, Masson stain, and TdT assay （TUNEL reaction） on 21st and 84th day after IL-6 mAb therapy in order to assess the therapeutic role. Spleen cells were analyzed by flow cytometry to illustrate Thl7 and Treg ceils？ number and function. The serum concentration of IL-6, IL-10, IL-17, and TGF-3 in each group was measured by ELISA, concentration of SYAT3, RORyt, and Foxp3 mRNA in each group was determined with RT-PCR. Spleen cells derived from EAM were stimulated by IL-6 mAb/n v/tro, and the con centration of IL-10, IL-17 and TGF-β was measured by EIJ.qA. Results： Inflammation score, fibrosis score, and apoptesis index in IL-6 mAb intervention group were significantly decreased as compared with those in EAM group （ P 〈 0.01）. The number of Thl7 and Treg cells in EAM group on the 21st day （experimental acute peak stage） were increased, and those in intervention group on the 2Pt day were significantly inhibit ed （ P 〈 0. O1 ）. The concentration of serum IL-6, IL-10, IL-17 and TGF-~ in intervention group on the 21st day was decreased dramatically in comparison with that in EAM group on the same day （ P 〈 0.01）. The levels of peripheral blood STAT3, RORTt, Foxp3 mRNA in intervention group on the 21st day was decreased significantly as compared with that in EAM group （ P 〈 0.01）. The expression of IL-10, IL-17 and TGF- β was increased significantly （ P 〈 0.01 ） by stimulation of IL-6 mAb on spleen cells derived from EAM /n v/tro. Conchlsions： IL-6 mAb could neutralize IL,-6, and ameliorate myocarditis and reduce heart autoimmune responses. IL-6 mAb has significantly protective effects on EAM by suppressing Thl7 and Treg cells.