Dandrea T, Tu B, Blomberg A, Sandström T, Sköld M, Eklund A, Cotgreave I
Division of Toxicology, Karolinska Institute, Stockholm, Sweden.
Hum Exp Toxicol. 1997 Oct;16(10):577-88. doi: 10.1177/096032719701601005.
Human alveolar macrophages (AMs) obtained from smokers and non-smokers by bronchoalveolar lavage (BAL) were subjected to various concentrations of NO2 in an inverted monolayer exposure model. Culture supernatants were collected 4 h after the exposure and assayed for secreted TNF-alpha, IL-1 beta, IL-8 and MIP-1 alpha. The steady state levels of the mRNAs for these cytokines were also analysed in the cells. The adherence of BAL cells to plastic prior to exposure to the gas elevated the steady state mRNA levels of all four cytokines tested in smoker's cells and that of TNF-alpha and IL-1 beta, but not IL-8 (MIP-1 alpha not tested), in non-smoker's cells. Interestingly, adherent cells from non-smokers released circa 15-, 3-, 1.5- and 3-fold the amounts of IL-1 beta, IL-8, TNF-alpha and MIP-1 alpha, respectively, than smoker's cells during control incubation or exposure to air. A 20 min exposure to NO2 (5 or 20 p.p.m.) did not increase the secretion of any of the cytokines from either cell type. In contrast, NO2 caused a concentration-dependent inhibition of the secretion of all cytokines except IL-1 beta from smoker's cells. Additionally, NO2 greatly diminished the release of all cytokines in response to further treatment with lipopolysaccharide (LPS). In contrast, only the secretion of TNF-alpha from non-smoker's cells was inhibited by the gas in a concentration-dependent manner, whilst LPS-induced secretion of the cytokines was not affected by the gas. The steady state levels of the respective mRNAs for each of the cytokines were not significantly affected in smoker's cells by exposure to NO2, except for a negative, dose-dependent trend in the case of TNF-alpha. Nitrogen dioxide also failed to elevate the levels of the mRNAs in non-smoker's cells but, again, tended to diminish the levels, particularly of IL-1 beta mRNA. However, exposure to the gas inhibited LPS-induced accumulation of cytokine mRNAs in smoker's cells only. The data suggest that macrophage-derived cytokine mediators of the sepsis response may not play a role in the generation of NO2-induced inflammation in the human lung. Conversely, the gas seems to non-specifically inhibit the release and/or production of cytokines, particularly from smoker's cells, at the post-transcriptional level, and impairs the ability of the cells to increase the transcription and release of the cytokines in response to bacterial LPS. The fact that NO2 seriously impaired the already diminished capacity of smoker's cells to release several important pro-inflammatory cytokines, both under control conditions and in response to LPS, strongly suggest that the inhalation of NO2 in cigarette smoke may contribute to impairing host defence against infection in the lung.
通过支气管肺泡灌洗（BAL）从吸烟者和非吸烟者获取的人肺泡巨噬细胞（AMs），在倒置单层暴露模型中暴露于不同浓度的二氧化氮（NO₂）。暴露4小时后收集培养上清液，检测其中分泌的肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）、白细胞介素-8（IL-8）和巨噬细胞炎性蛋白-1α（MIP-1α）。同时也分析了这些细胞中这些细胞因子mRNA的稳态水平。在暴露于气体之前，BAL细胞与塑料的黏附提高了吸烟者细胞中所检测的所有四种细胞因子以及非吸烟者细胞中TNF-α和IL-1β（未检测IL-8的MIP-1α）的mRNA稳态水平。有趣的是，在对照孵育或暴露于空气期间，来自非吸烟者的黏附细胞分泌的IL-1β、IL-8、TNF-α和MIP-1α的量分别比吸烟者细胞多约15倍、3倍、1.5倍和3倍。暴露于NO₂（5或20 ppm）20分钟并未增加任何一种细胞类型中细胞因子的分泌。相反，NO₂对吸烟者细胞中除IL-1β外的所有细胞因子的分泌产生浓度依赖性抑制。此外，NO₂极大地减少了脂多糖（LPS）进一步处理后所有细胞因子的释放。相比之下，该气体仅以浓度依赖性方式抑制非吸烟者细胞中TNF-α的分泌，而LPS诱导的细胞因子分泌不受该气体影响。除TNF-α呈负的剂量依赖性趋势外，暴露于NO₂对吸烟者细胞中每种细胞因子各自的mRNA稳态水平没有显著影响。二氧化氮也未能提高非吸烟者细胞中mRNA的水平，但同样倾向于降低其水平，尤其是IL-1β mRNA的水平。然而，暴露于该气体仅抑制吸烟者细胞中LPS诱导的细胞因子mRNA积累。数据表明，脓毒症反应中巨噬细胞衍生的细胞因子介质可能在人肺中二氧化氮诱导的炎症产生中不起作用。相反，该气体似乎在转录后水平非特异性地抑制细胞因子的释放和/或产生，尤其是来自吸烟者细胞的，并且损害细胞响应细菌LPS增加细胞因子转录和释放的能力。NO₂严重损害了吸烟者细胞在对照条件下以及对LPS响应时已经降低的释放几种重要促炎细胞因子的能力，这一事实强烈表明香烟烟雾中吸入NO₂可能导致损害肺部宿主抗感染防御能力。
