Department of Immunology, Medical School, Shiraz University of Medical Sciences, Shiraz, 71348-45794, Iran.
Department of Immunology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Daru. 2018 Dec;26(2):215-227. doi: 10.1007/s40199-018-0229-x. Epub 2018 Nov 26.
CD4 T cell subsets including regulatory T cells (Tregs), Th1 and Th17 are critical for control and development of inflammation and autoimmunity. We investigated the in vitro and in vivo effects of silymarin, a well-known herbal medicine on differentiation and function of Tregs and Th1 and Th17 responses. For in vitro study, mice splenocytes treated with 20-30 μg/ml silymarin were evaluated for gene expressions of specific transcription factors and cytokines of CD4 T cell subsets using real-time PCR. Induction of Treg cell development in the presence of silymarin was performed on isolated naïve CD4 T cells. Effect of silymarin-induced Tregs on T cell suppression was determined by CFSE labeling method. Results of this part showed that silymarin significantly decreased IFNγ, RORγt and IL-17 gene expressions and upregulated Foxp3, TGF-β and IL-10 mRNA. More silymarin-enhanced naïve CD4 T cells differentiated to Tregs (67%) than the control (47%). Silymarin-induced Tregs reduced proliferation of naïve activated T cells (<50%). For in vivo study, mice were immunized with ovalbumin (Ova) on days 1 and 14. Silymarin (100 mg/Kg) was intraperitoneally administered two days before the first Ova challenge followed by on every day for two weeks. Splenocytes were then isolated for assessment of CD4 T cell subsets and ex vivo analysis using flow cytometry. Treatment of Ova-immunized mice with silymarin increased Tregs (11.24 ± 1.2%, p < 0.01(but decreased Th1 (1.72 ± 0.4%, p < 0.001) and Th17 (1.07 ± 0.04%, p < 0.001) cells. Ex vivo Ova challenge of splenocytes from Ova-immunized mice treated with silymarin decreased proliferation of splenocytes, IFNγ (2.76% of control) and IL-17 (<8%) along with increased TGF-β (59.7%) expressions in CD4T-bet, CD4RORγt and CD4Foxp3 T cells, respectively. In conclusion, silymarin promoted Treg differentiation and function and decreased Th1 and Th17 cells. Silymarin may differentially regulate CD4 T cell responses which can provide potential benefits for its use as treatment of immune-related diseases. Graphical abstract ᅟ.
CD4 T 细胞亚群包括调节性 T 细胞（Tregs）、Th1 和 Th17，对于控制和发展炎症和自身免疫至关重要。我们研究了水飞蓟素（一种著名的草药）对 Tregs 和 Th1、Th17 反应的分化和功能的体外和体内作用。在体外研究中，用 20-30μg/ml 水飞蓟素处理小鼠脾细胞，用实时 PCR 检测 CD4 T 细胞亚群特定转录因子和细胞因子的基因表达。在水飞蓟素存在的情况下诱导 Treg 细胞的发育，在分离的幼稚 CD4 T 细胞上进行。通过 CFSE 标记法确定水飞蓟素诱导的 Tregs 对 T 细胞抑制的影响。这部分的结果表明，水飞蓟素显著降低 IFNγ、RORγt 和 IL-17 的基因表达，并上调 Foxp3、TGF-β 和 IL-10 mRNA。与对照组（47%）相比，更多的水飞蓟素增强的幼稚 CD4 T 细胞分化为 Tregs（67%）。水飞蓟素诱导的 Tregs 降低了幼稚活化 T 细胞的增殖（<50%）。在体内研究中，用卵清蛋白（Ova）在第 1 天和第 14 天免疫小鼠。在第一次 Ova 挑战前两天腹腔内给予水飞蓟素（100mg/kg），随后每周两次。然后分离脾细胞，用流式细胞术进行 CD4 T 细胞亚群评估和体外分析。用水飞蓟素治疗 Ova 免疫小鼠增加了 Tregs（11.24±1.2%，p<0.01（但减少了 Th1（1.72±0.4%，p<0.001）和 Th17（1.07±0.04%，p<0.001）细胞。体外 Ova 刺激来自用水飞蓟素治疗的 Ova 免疫小鼠的脾细胞降低了脾细胞的增殖、IFNγ（对照的 2.76%）和 IL-17（<8%），同时在 CD4T-bet、CD4RORγt 和 CD4Foxp3 T 细胞中分别增加了 TGF-β（59.7%）的表达。总之，水飞蓟素促进了 Treg 的分化和功能，并减少了 Th1 和 Th17 细胞。水飞蓟素可能会对 CD4 T 细胞反应进行差异调节，这可为其在免疫相关疾病治疗中的应用提供潜在益处。
