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探讨在人气道上皮细胞核因子_κB(NF_κB)的激活情况及抗氧化剂N_乙酰半胱氨酸(NAC)对NF_κB的作用机理。方法应用炎前性细胞因子TNF_α刺激正常人气道上皮细胞株(16HBE)和肿瘤病人气道上皮细胞株 (H292) ,利用Western_Blot免疫印迹电泳和ELISA实验检测NF_κB的表达和IL_8的分泌水平。结果TNF_α在体外能刺激激活人气道上皮细胞16HBE和H292的NF_κB表达 ,刺激后2～4h最高 ,6h后有所下降。随着TNF_α刺激量的增加 ,NF_κB活性也随之升高。TNF_α刺激气道上皮细胞后IL_8的分泌水平增加。加入NAC后可抑制NF_κB激活 ,IL_8分泌水平随之降低 ;同时发现NAC能以一种剂量依赖方式发挥作用。结论NAC可通过阻断NF_κB激活的信号转导 ,参与细胞因子和炎症介质表达的转录调控 ,在呼吸系气道炎症控制中起着一定的作用。
To investigate the activation of nuclear factor-κB (NF_κB) in human airway epithelial cells and the mechanism of action of antioxidant N_ (acetylcysteine) on NF_κB. Methods The normal human airway epithelial cell line (16HBE) and the tumor patient airway epithelial cell line (H292) were stimulated with proinflammatory cytokines TNF_α. The expression of NF_κB and the secretion of IL_8 were detected by Western blotting and ELISA. Results TNF_α stimulated the expression of NF_κB in human airway epithelial cells 16HBE and H292 in vitro, which was the highest at 2 ~ 4h after stimulation, but decreased after 6h. NF_κB activity increased with the increase of TNF_α stimulation. TNF_α stimulates the secretion of IL-8 in airway epithelial cells. After adding NAC, the activation of NF_κB was inhibited and the level of IL_8 secretion was decreased. At the same time, NAC was found to play a role in a dose-dependent manner. Conclusion NAC plays a role in the control of respiratory airway inflammation by blocking the signal transduction of NF_κB activation and participating in the transcriptional regulation of cytokines and inflammatory mediators.