黄连素对T淋巴细胞活化和增殖的抑制作用

目的:研究黄连素(Ber)对T细胞体外活化和增殖的影响及作用机制。方法:正常人外周血全血培养,以植物血凝素(PHA)或佛波醇酯(PDB)加离子霉素(Ion)刺激活化淋巴细胞,双荧光染色及溶血获取有核细胞后,以流式细胞仪分析T细胞表达活化抗原CD69和CD25的水平,并以碘化丙锭染色分析细胞周期分布,7-AAD活染分析细胞死亡率。结果:浓度为100μmol/L和50μmol/L的Ber对PDB+Ion或PHA激活T细胞表达CD69有明显抑制,而25μmol/L的Ber抑制效应无显著性;随时间延长,对CD69表达的抑制程度下降;对于CD25表达,上述3个浓度的Ber抑制作用均有显著性,且呈剂量依赖性。同时,这3个浓度的Ber均能明显阻止淋巴细胞进入S期和G₂/M,对细胞周期的抑制作用没有时相特异性。活染分析显示Ber对淋巴细胞无明显细胞毒性。结论:Ber通过干扰早期活化信号转导通路而抑制T细胞活化和增殖,发挥其免疫抑制作用。

Inhibitory effect of berberine on the activation and proliferation of T lymphocytes

AIM: To investigate the effect of berberine (Ber) on the activation and proliferation of T lymphocytes and its mechanism of action. METHODS: Whole peripheral blood from normal subjects was stimulated with phytohemagglutinin (PHA) or phorbol ester (PDB) plus ionomycin (Ion) and the expression levels of CD69 and CD25 were evaluated with flow cytometry after the staining with appropriate fluorescent monoclonal antibody. The distribution of cell cycles was analyzed by propidium iodide staining and dead cells by 7-aminoactinomycin live staining. RESULTS: 100 μmol/L and 50 μmol/L of Ber had significant inhibition of the expression of CD69 on T cells stimulated with PDB plus Ion or PHA, while effect of 25 μmol/L Ber was not significant. And as time of action extended, the extent of inhibition decreased. For the expression of CD25, Ber at the concentrations as above all exerted significant inhibitory effect in a dose-dependent manner. Moreover, Ber could block lymphocytes cell cycle progression from G₀/G₁ phase to S and G₂/M phase without phase specificity. Besides, live staining analysis revealed that Ber did not have significant cytotoxicity on lymphocytes. CONCLUSIONS: Ber significantly inhibits the expression of early and mid activation antigens of T cells and also blocks the progression of lymphocytes cell cycles. These results suggest that Ber exerts immunosuppression effect through inhibiting the activation and proliferation of T cells.