中文摘要：

目的探讨Toll样受体4（TLR4）在二氧化硅诱导巨噬细胞肿瘤坏死因子α（TNFα）合成过程中的介导作用。方法将二氧化硅的粉尘悬液与人巨噬细胞株THP-1温育，收集细胞培养液，利用酶联免疫吸附（ELISA）方法测定培养液中TNFα的含量。为了解TLR4在二氧化硅诱导TNFα合成过程中的作用，用TLR4受体的中和抗体（HTA125，20μg／ml）预处理THP-1细胞，观察该处理对二氧化硅上述作用的影响。此外，利用可表达野生型或突变型TLR4的小鼠巨噬细胞株，进一步比较二氧化硅诱导两型细胞合成TNFα水平的差异。结果100μg／ml二氧化硅刺激THP—1细胞4、8h，可致细胞TNFα的释放量升高[分别为（4．71±0．84）、（6．22±0．58）pg／ml]，为对照组[（3．18±0．41）pg／ml]的1．48和1．96倍，差异有统计学意义（P〈0．05）。用HTA125抗体预处理THP-1细胞，可致二氧化硅诱导细胞释放TNFα的量降低27％。同表达野生型TLR4的小鼠巨噬细胞相比，表达突变型TLR4细胞在二氧化硅刺激后TNFα的释放量降低30％。结论TLR4在二氧化硅诱导TNFα合成过程中起一定的作用。

英文摘要：

Objective To characterize the role of Toll-like receptor 4 （TLR4） in silica-induced production of tumor necrosis factor α（TNFα from macrophage cell line. Methods The human maerophage cell line THP-1 was incubated with silica suspension. Cell media were collected and TNFα levels in the supernatants measured with ELISA. To examine the involvement of TLR4 in silica-induced TNFα release, the neutralizing antibody （HTA 125 ） against human TLR4 receptor was employed to pretreat THP-1 cells prior to silica treatment. Moreover, murine maerophages expressing wild type or mutated TLR4 were also treated with silica to verify the effect of TLR4 in silica-induced TNFα release. Results Compared with the control group[（3.18±0.41 ） pg/ml], the TNFα release in cells exposed to 100 μg/ml silica for 4 h and 8 h [（4.71±0.84）,（6.22±0.58 ） pg/ml, respectively] increased 1.48 and 1.96 fold, respectively. Pretreatment of THP-1 cells with 20 μg/ml HTA 125 antibody significantly blocked silica-induced TNFα release by 27%. Furthermore, the TNFα content released from cells expressing mutated TLR4 reduced by 30% in compared with that from the cells expressing wild type TLR4 after silica stimulation. Conclusion TLR4 mediates silica-induced TNFα release from macrophages.