黄芪甲苷对体外高迁移率族蛋白B1介导小鼠调节性T细胞免疫功能的影响

目的：观察高迁移率族蛋白B1（HMGB1）刺激的小鼠调节性T细胞（CD4＋CD25＋Treg）对CD4＋CD25-T细胞免疫功能的影响及黄芪甲苷（AST Ⅳ）对HMGB1介导Treg免疫功能的拮抗作用。方法采用清洁级BALB/c小鼠，活杀后分离脾脏的CD4＋CD25＋Treg、CD4＋CD25-T细胞，将CD4＋CD25-T细胞在48孔板上随机分为4组（每组12孔）培养，对照组：单纯CD4＋CD25- T细胞；Treg实验组：CD25＋∶CD25-按照1∶10比例加入100μl CD4＋CD25＋Treg与CD4＋CD25-T细胞共同培养；HMGB1＋Treg组：按CD25＋∶CD25-比例为1∶10加入100μl经HMGB1（1μg/ml）刺激72 h的Treg与CD4＋CD25-T细胞进行共培养；HMGB1＋AST IV＋Treg组： CD25＋∶CD25-按照1∶10比例加入100μl经HMGB1（1μg/ml）、AST IV（100μg/ml）刺激72 h的CD4＋CD25＋Treg与CD4＋CD25-T细胞共同培养。以上4组均于培养后72 h重新分离收集CD4＋CD25-T细胞及其上清液，采用噻唑蓝（MTT）法检测脾脏CD4＋CD25-T细胞增殖活性；ELISA法检测CD4＋CD25-T细胞活化核因子（NFAT）活性、孵育上清液IL-2表达。结果将CD4＋CD25＋Treg加入CD4＋CD25-T细胞培养后，CD4＋CD25-T细胞增殖活性受到抑制（0.166±0.039），P＜0.01，NFAT活性（0.156±0.035）、IL-2水平（2.38±0.58）pg/ml均较对照组下降（P＜0.01）。加入经HMGB1刺激的Treg后，CD4＋CD25-T细胞增殖活性受抑制程度逆转（0.477±0.097），P＜0.01。与CD4＋CD25＋Treg组比较，HMGB1＋Treg组NFAT活性（0.409±0.094）、IL-2（4.55±0.96）pg/ml均升高（P＜0.01）。与HMGB1＋Treg组比较，HMGB1＋AST Ⅳ＋Treg组CD4＋CD25-T细胞增殖受抑制程度加重（0.287±0.052）、NFAT活性（0.261±0.046）、IL-2水平（2.73±0.62）pg/ml降低（P＜0.01）。结论 HMGB1在体外可抑制小鼠Treg免疫功能发挥，而ASTⅣ可拮抗HMGB1对Treg免疫功能的抑制作用，表明其对HMGB1介导的促炎效应具有治疗作用。

The effect and mechanism of Astragaloside IV on immune function of regulatory T cell mediated by high mobility group box 1 protein in vitro

Objective Based the previous studies, the present study was performed to investigate the antagonistic effects of different doses of Astragaloside IV on the immune function of Treg mediated by HMGB1 in vitro and its potential mechanism.Methods CD4＋CD25-T cells isolated from the spleens of male BABL/c mice by magnetic beads were seeded on 48-well cell culture plates and were randomly divided into four groups as follows（12 holes per group）. Normal control group： CD4＋CD25-T cells were cultured merely. Treg group： Tregs（100μl） and CD4＋CD25-T cells were co-cultured in ratio of 1：10. HMGB1＋Treg group： Tregs（100μl） stimulated by HMGB1（1μg/ml） for 72 h and CD4＋CD25-T cells were co-cultured in ratio of 1∶10. HMGB1＋AST IV＋Treg group： Tregs（100μl） stimulated by HMGB1（1μg/ml） and AST IV（100μg/ml）for 72 h were co-cultured with CD4＋CD25-T cells in ratio of 1：10. CD4＋CD25-T cells and supernatants were again collected on post-culture 72 hour. The proliferation of CD4＋CD25- T cells was analyzed by MTT test, the activity of NFAT and the contents of cytokines of IL-2 released into supernatants were also determined by means of ELISA. Results When CD4＋CD25-T cells were co-cultured with Tregs, the cell proliferation（0.166±0.039） and the levels of NFAT（0.156±0.035） and IL-2（2.38±0.58） in supernatant were markedly decreased as compared with those in the control group（P〈0.01）. However, the contrary results were found when CD4＋CD25-T cells were co-cultured with Treg stimulated by HMGB1. Compared with those in the（HMGB1＋Treg） group, the contrary results were showed with a dose-dependent in the（HMGB1＋ASTⅣ＋Treg） group.Conclusion ASTⅣcan rivalry the effects of HMGB1 on immune function of Treg in vitro, this result indicate that ASTⅣhas the therapeutic action on inflammation promoted by HMGB1.