脂多糖活化的大鼠肺泡巨噬细胞TNF-α产生的新机制

目的：探讨脂多糖（LPS）活化的肺泡巨噬细胞中低氧诱导因子－1α（HIF-1α）的表达及其在肺泡巨噬细胞产生肿瘤坏死因子α（TNF-α）中的作用。 方法： 应用HIF-1α 诱骗法（HIF-1α decoy）抑制其作用，并用Western blotting、半定量RT-PCR、酶联免疫吸附法（ELISA）分别检测HIF-1α蛋白、mRNA的表达和TNF-α的产生。 结果： HIF-1α蛋白含量在LPS组（1.95±0.57）和HIF-1α decoy组（1.89±0.59）均明显高于对照组（0.41±0.14，P＜0.05）；HIF-1α mRNA的表达在对照组（0.7838±0.3183）、LPS组（0.7622±0.3387）和HIF-1α decoy组（0.8155±0.3594）之间无显著差异（P>0.05）；LPS刺激24 h后，大鼠肺泡巨噬细胞TNF-α的产生明显高于对照组（61 ng/L vs 156 ng/L, P<0.05），抑制HIF-1α后TNF-α的产生明显低于LPS刺激组（90 ng/L vs 156 ng/L, P<0.05），但 HIF-1α decoy组TNF-α的产生仍然高于对照组（61 ng/L vs 94 ng/L, P<0.05）。 结论： 大鼠肺泡巨噬细胞在LPS的刺激下HIF-1α蛋白的稳定性增强使其表达明显上调，并且促进TNF-α的产生，提示HIF-1α在肺部慢性炎症性疾病如COPD的发病机制中可能有重要作用。

The mechanism of lipopolysaccharide-activated rat alveolar macrophages producing tumor necrosis factor alpha

AIM: To investigate the expression of hypoxia inducible factor-1alpha (HIF-1α) and the role of HIF-1α in tumor necrosis factor alpha (TNF-α) production in rat alveolar macrophages activated by lipopolysaccharide (LPS). METHODS: HIF-1α function was inhibited by using the method of HIF-1α decoy. Western blotting and semiquantitative RT-PCR were applied to determine the expression of HIF-1α protein and mRNA, respectively. The production of TNF-α was determined with ELISA. RESULTS: The content of HIF-1α protein in LPS group (1.95±0.57) and HIF-1α decoy group (1.89±0.59) were 4.8 times and 4.6 times higher than that in control group (0.41±0.14), respectively. The expression of HIF-1α mRNA showed no difference among three groups (F=3.14，P>0.05). The production of TNF-α in LPS group was higher than that in control group (61 ng/L vs 156 ng/L, q=5.12, P<0.05) and HIF-1α decoy group (90 ng/L vs 156 ng/L, q=4.63, P<0.05), respectively. However, the content of TNF-α in HIF-1α decoy group was still higher than that in control group (61 ng/L vs 94 ng/L, q=4.47, P<0.05). CONCLUSION: The enhanced stability of HIF-1α protein results in the marked upregulation of its protein and HIF-1α is contributed to the production of TNF-α in LPS-stimulating rat alveolar macrophages. It is indicated that HIF-1α plays important role in the pathogenesis of chronic inflammation involved in diseases such as COPD.