肠致病性大肠杆菌感染时血清TNF-α和IL-1β含量的检测及意义

Effect of infection from EPEC on the production of tumor necrosis factor-α and IL-1β in serum and the apoptosis of THP-1

目的研究肠致病性大肠杆菌(enteropathogenic escherichia coli,EPEC)感染人单核白血病细胞系THP-1细胞时,血清肿瘤坏死因子-α(TNF-α)和IL-1β水平的动态变化及与其THP-1细胞凋亡的关系。方法以Annexin V FITC/PI双染流式细胞仪检测THP-1细胞凋亡率,以MTT法测定细胞存活率;并用酶联免疫吸附测定法动态检测感染24h内细胞培养上清中TNF-α和IL-1β浓度的变化。结果EPEC感染THP-1细胞后TNF-α和IL-1β活性均显著增加,峰值分别出现在感染后6及12h,而后逐渐下降,IL-1β活性至感染后24h仍高于对照组;THP-1细胞凋亡率在感染后逐渐增高,至24h达高峰。结论EPEC可激活多种炎症介质和诱导THP-1凋亡,EPEC感染THP-1细胞后TNF-α和IL-1β水平的升高具有重要作用。

[Objective] To investigate the productive kinetics of tumor necrosis factor-or （TNF-α） and IL-1β in serum and the relation between TNF-α, IL-1β and the apoptosis of THP-1 with infection induced by EPEC. [Methods] The cell cytotoxicity and apoptosis rate was determined by MTr assay and Annexin V FITC/PI stain, the changes in the centents of TNF-α and IL-1β of the supernatant of the cell culture were assessed by ELISA 3, 6, 12 and 24 hours after infection. [Results] It was found that the TNF-α and IL-1β was in a single peak manner （P 〈0.01）, and reached its highest level at 6 and 12 hours respectively after infection, then both went down, but IL- 1β was still significantly higher than that of control group at 24 h. It was showed that apoptosis of THP-1 was gradually increased, reaching their peak 24 hours after infection. [Conclusion] These results suggested that infection of EPEC can initiate inflammatory cytokines response, and induce THP-1 apoptosis. The apoptosis of THP-1 is not completely mediated by TNF-α and IL-1β.