中文摘要：

目的探讨锌对镉诱导的人未成熟树突状细胞（iDC）毒性的影响。方法分离人周围血单核细胞（PBMC）并诱导为iDC后,分组给予生理氯化钠溶液（对照组）、氯化镉（CdCl2组）、硫酸锌（ZnSO4组）、锌预处理后加氯化镉（Zn＋Cd组）、锌离子特异性螯合剂（TPEN）预处理后加氯化镉（TPEN＋Cd组）处理。噻唑蓝（MTT）颜色反应法检测细胞活力;单细胞凝胶电泳（SCGE）检测DNA链断裂损伤;吖啶橙（AO）与碘化丙啶（PI）核双染观察细胞凋亡并通过流式细胞仪检测凋亡细胞中染色体断裂的亚二倍体（SubG1）。结果 CdCl2组iDC活力抑制率随CdCl2呈剂量依赖性显著增高（P〈0.05）;与ZnSO4组或CdCl2组相比,Zn＋Cd组和TPEN＋Cd组细胞活力抑制率明显升高（P〈0.05）;相同CdCl2剂量（20μmol/L）时,Zn＋Cd组和TPEN＋Cd组细胞的彗星尾长和尾矩明显增大（P〈0.05）;各处理组出现凋亡细胞核染色和SubG1阳性细胞比例明显增加。结论镉化合物暴露导致iDC活力降低,其诱导的细胞毒性明显高于锌;细胞内锌稳态干预可增加镉介导的iDC内DNA损伤相关的毒作用敏感性。

英文摘要：

Objective To explore the impacts of zinc compounds on the cytotoxicity of human immature dendritic cells（iDC） administrated by cadmium in vitro.Methods iDCs were derived from peripheral blood mononuclear cells.The iDC cellular models were conducted by different groups treated with normal saline（negative control）,cadmium chloride（CdCl2）,zinc sulfate（ZnSO4）,ZnSO4 pretreatment for 12 h（Zn＋Cd） or zinc chelator pretreatment for 4 h（TPEN＋Cd） followed by CdCl2 administration,respectively.MTT assay was used to test the cell viability.Single cell gel electrophoresis（SCGE） was used to detect the DNA strand breaks with alkaline comet assay.Cell apoptosis analysis of nuclear morphology was performed through double-dying with acridine orange（AO） and propidine iodide（PI）,while Flow cytometry was used for the analysis of SubG1 proportion in cell cycle.Results Compared with the control group,the inhibition of iDC viability increased significantly with the increase of CdCl2 doses in a dose-dependent manner（P0.05）.Compared with ZnSO4 group or CdCl2 group,the cellular viability inhibition in Zn＋Cd group and TPEN＋Cd group increased significantly（P0.05）.The comet tail length and tail moment in Zn＋Cd and TPEN＋Cd group increased significantly compared with those in CdCl2 group at the same concentration（20 μmol/L Cd2＋,P0.05）.There were apoptotic nuclear dying in cellular morphology with remarkable increase of the proportion of SubG1 apoptosis cell in various Cd-treated groups.Conclusion The exposure of Cd2＋ compound would lead to the decrease of iDC cellular viability,while the cytotoxicity of iDCs induced by Cd2＋ was stronger than that by Zn2＋.The disruption of cellular zinc homeostasis in iDCs could sensitize the cytotoxic response associated with Cd2＋-mediated DNA damages.