Free radical producing activity and intracellular signal transduction mechanisms of phagocytes by heavy metals

研究氧化锌（ZnO）对腹腔洗脱大鼠中性粒细胞和小鼠巨噬细胞样细胞Raw 264.7的激活机制，探讨氧化锌诱发金属烟雾热的病因机制。添加谷胱甘肽（GSH）和硫醇类化合物可增强氧化锌对吞噬细胞的激活作用。如果将氧化锌作为兴奋剂添加到中性粒细胞中，NADPH氧化酶可以通过gtp结合蛋白、蛋白激酶C、酪氨酸激酶、胞内钙和细胞膜CR3等胞内信号转导途径产生超氧化物（O2^-）和过氧化氢（H2O2）。在氧化锌中加入谷胱甘肽后，除CR3外，氧化锌的活性氧的生成还依赖于FcgammaR。研究了氧化锌和氧化锌+谷胱甘肽对中性粒细胞活化的差异。氧化锌对中性粒细胞的激活可能依赖于通过NADPH氧化酶和一氧化氮合酶（NOS）产生O2^-和氧化亚硝酸盐（ONOO^-）。氧化锌和谷胱甘肽对中性粒细胞的激活可能通过激活主要定位于线粒体的单胺氧化酶（MAO）参与了H2O2的升高。这些结果不仅为H2O2的来源与核转录因子的激活和细胞凋亡的病因学提供了新的证据，而且还发现了MAO与细胞内信号转导机制之间的关系。此外，从Raw 246.7的结果来看，GSH促进了ZnO颗粒的吞噬作用。从本研究项目推测，锌烟热除了由ZnO颗粒引起外，还可能由内在因子GSH引起。

The activation mechanisms of intraperitoneal-eluted rat neutrophils and mouse macrophage -like cell line Raw 264.7 by zinc oxide (ZnO) was investigated to explore the etiological mechanisms of metal fume fever induced by ZnO.The activation of phagocytes by ZnO was enhanced by the addition of glutathione (GSH) and thiol compounds. Superoxide (O2^-) and hydrogen peroxide (H2O2) may be produced by NADPH oxidase via the intracellular signal transduction pathway such as GTP-binding protein, protein kinase C, tyrosine kinase, and intracellar calcium and membraneous CR3 if ZnO was added as a stimulant to neutrophils. If GSH was added to ZnO, the production of acitive oxygen species was dependent on FcgammaR in addition to CR3. The differnce in the activation of neutrophils by ZnO and ZnO plus GSH was investigated. The activation of neutrophils by ZnO may be dependent on the production of O2^- and peoxynitrite (ONOO^-) via NADPH oxidase and nitric oxide synthase (NOS). The activation of neutrophils by ZnO plus GSH may participated in the elevated H2O2 via the activation of monoamine oxidase (MAO) mainly localized in mitochodrium. These results suggest pot only the new evidence of the origin of H2O2 associated with the activation of nuclear transcription factor and the etiology of apoptosis but also the discovery of the relationship between MAO and intracellar signal transduction mechanisms. Moreover, from the results of Raw 246.7, GSH promoted the cleaning of ZnO particles by phagocytosis.From this research project, it is speculated that zinc fume fever may be caused by the intrinsic factor GSH in addition to ZnO particles.