Ye J, Ding M, Leonard S S, Robinson V A, Millecchia L, Zhang X, Castranova V, Vallyathan V, Shi X
Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown 26505, USA.
Mol Cell Biochem. 1999 Dec;202(1-2):9-17. doi: 10.1023/a:1007078915585.
Apoptosis is a physiological mechanism for the control of DNA integrity in mammalian cells. Vanadium induces both DNA damage and apoptosis. It is suggested that vanadium-induced apoptosis serves to eliminate DNA-damaged cells. This study is designed to clarify a role of reactive oxygen species in the mechanism of apoptosis induced by vanadium. We established apoptosis model with murine epidermal JB6 P+ cells in the response to vanadium stimulation. Apoptosis was detected by a cell death ELISA assay and morphological analysis. The result shows that apoptosis induced by vanadate is dose-dependent, reaching its saturation level at a concentration of 100 microM vanadate. Vanadyl (IV) can also induce apoptosis albeit with lesser potency. A role of reactive oxygen species was analyzed by multiple reagents including specific scavengers of different reactive oxygen species. The result shows that vanadate-induced apoptosis is enhanced by NADPH, superoxide dismutase and sodium formate, but was inhibited by catalase and deferoxamine. Cells exposed to vanadium consume more molecular oxygen and at the same time, produce more H2O2 as measured by the change in fluorescence of scopoletin in the presence of horseradish peroxidase. This change in oxygen consumption and H2O2 production is enhanced by NADPH. Taken together, these results show that vanadate induces apoptosis in epidermal cells and H2O2 induced by vanadate plays a major role in this process.
细胞凋亡是哺乳动物细胞中控制DNA完整性的一种生理机制。钒可诱导DNA损伤和细胞凋亡。有人认为，钒诱导的细胞凋亡有助于清除DNA受损细胞。本研究旨在阐明活性氧在钒诱导的细胞凋亡机制中的作用。我们建立了小鼠表皮JB6 P+细胞对钒刺激反应的细胞凋亡模型。通过细胞死亡ELISA检测和形态学分析来检测细胞凋亡。结果表明，钒酸盐诱导的细胞凋亡呈剂量依赖性，在钒酸盐浓度为100 microM时达到饱和水平。钒（IV）也能诱导细胞凋亡，但其效力较小。通过多种试剂，包括不同活性氧的特异性清除剂，分析了活性氧的作用。结果表明，NADPH、超氧化物歧化酶和甲酸钠可增强钒酸盐诱导的细胞凋亡，但过氧化氢酶和去铁胺可抑制其凋亡。暴露于钒的细胞消耗更多的分子氧，同时，在辣根过氧化物酶存在下，通过 scopoletin荧光变化测量，产生更多的H2O2。NADPH可增强这种氧消耗和H2O2产生的变化。综上所述，这些结果表明钒酸盐可诱导表皮细胞凋亡，钒酸盐诱导产生的H2O2在这一过程中起主要作用。
