黄芪多糖通过NF-κB诱导巨噬细胞产生NO和TNF-α

目的 通过体外试验研究黄芪多糖(Astragalus mongholicus polysaccharides,ASP)激活巨噬细胞产生NO和TNF-α的分子机制和细胞内信号转导机制.方法 黄芪多糖刺激RAW264.7细胞,用Western blot方法 检测细胞核内核转录因子-κB(NF-κB)的变化.用Griess还原法观察黄芪多糖对巨噬细胞释放NO的作用的影响以及NF-κB抑制剂对黄芪多糖诱导巨噬细胞释放NO作用和分泌TNF-α的影响.ELISA法检测黄芪多糖对巨噬细胞分泌肿瘤坏死因子-α(TNF-α)的变化.结果 100μg/ml黄芪多糖刺激RAW264.7细胞,4 h后可引起细胞核内NF-κB含量显著增加,6 h达到顶峰.16 h后可显著诱导NO(18.9±1.5)μmol/L;P<0.01]释放和TNF-α分泌(81.2±16.7)pg/ml,P<0.01]的增加,以及诱导型一氧化氮合酶(iNOS)(23.54±2.41)U/mg蛋白质,P<0.01]活性的增加.NF-κB抑制剂吡咯烷二硫代氨基甲酸盐(PDTC)可明显抑制黄芪多糖诱导RAW264.7生成NO和分泌TNF-α.结论 NF-κB在黄芪多糖诱导巨噬细胞生成NO和TNF-α过程中发挥重要作用.

The role of nuclear factor-kappaB in the induction of nitric oxide and tumor necrosis factor-alpha by Astragalus mongholicus polysaccharides in macrophages

Objective To explore the molecular and cell signal transduction mechanism of Astragalus mongholicus polysaccharides (ASP) on macrophage. Methods After stimulating RAW264.7, the change in value of NF-κB was determined by Western blot. The induction of NO and secretion of TNF-α by ASP in macrophage was observed with or without inhibitor of NF-κB using Griess method. Moreover, protein levels of TNF-α secreted by macrophage were investigated with ELISA in respond to ASP. Results 4 h after stimulation by 100 μg/ml ASP, the concentration of NF-κB in nucleus increased significantly, peaked at 6 h. 16 h after stimulation by 100 μg/ml ASP, the activity of iNOS(23.54±2.41) U/mg protein; P<0.01], producton of NO (18.9±1.5)μmol/L, P<0.01] and level of TNF-α(81.2±16.7)pg/ml, P<0.0l] in macrophage were improved markedly. Blocking NF-κB with inhibitor results in decreased levels of NO and TNF-α. Conclusion The results suggest that NF-κB play an important role in induction of NO and TNF-α by ASP in macrophage.