NaAsO2 Treatment Research Articles

砷诱导蚕豆气孔保卫细胞死亡效应研究

PDF HTML阅读 XML下载 导出引用 引用提醒 砷诱导蚕豆气孔保卫细胞死亡的毒性效应 DOI: 10.5846/stxb201210171445 作者: 作者单位: 山西大学生命科学学院,山西大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（30870454，30470318）；教育部高等学校博士学科点基金项目（20070108007，20121401110007）；山西省回国留学人员科研资助项目（2012013） Arsenic induces guard cell death in leaf epidermis of Vicia faba Author: Affiliation: School of Life Science,Shanxi University,Shanxi University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用蚕豆（Vicia faba L.）叶面气孔保卫细胞，研究砷对细胞的毒性效应。结果表明，0.3-10 mg/L的NaAsO2能降低保卫细胞活性，使部分细胞死亡，死亡率随砷浓度升高而增高。死细胞中呈现核固缩、核崩解等典型程序性死亡特征，且泛caspase抑制剂Z-Asp-CH2-DCB能阻止NaAsO2诱发的细胞死亡。过氧化氢清除剂过氧化氢酶与NaAsO2共同作用时，细胞死亡率显著低于砷单独处理组，保卫细胞内Ca2+水平降低，具程序性死亡特征的细胞数减少；Ca2+特异性螯合剂EGTA亦能降低NaAsO2诱发的细胞死亡。研究结果表明，NaAsO2能诱发蚕豆保卫细胞程序性死亡，该过程由胁迫引发的ROS升高引起，ROS可能通过激活质膜Ca2+通道，使胞外Ca2+内流，造成胞内Ca2+浓度升高，进而诱导细胞程序性死亡。 Abstract:Arsenic is a highly toxic metalloid for all forms of life including plants. Arsenic enters in plants through phosphate transporters as a phosphate analogue or through aquaglycoporins. Uptake of arsenic in plant tissues can affect plant metabolism, causing various physiological disorders, structural abnormalities and even plant death. Oxidative stress is considered to be a key mechanism of arsenic toxicity.In this study, the effect of sodium arsenite (NaAsO2) on guard cell viability was investigated in detached epidermis of V. faba leaves. Epidermal strips were obtained from 4-week-old plants by peeling off the lower epidermis of V. faba leaves and incubated in 2-(N-morpholino) ethanesulfonic acid (MES) buffer containing some chemicals (NaAsO2 with or without some antagonists) for 3 h in white light at 23 ℃ as the treatments. After treatment, the epidermal strips were stained with fluorescein diacetate (FDA) to show cell viability, or with 2',7'-dichlorofluorescein diacetate (DCFH-DA) and fluo-3 acetomethoxyester (Fluo-3AM) respectively to indicate intracellular reactive oxygen species (ROS) and calcium ion (Ca2+) levels.The results of our experiments showed that NaAsO2 treatment significantly decreased cell viability and induced cell death in the concentration range of 0.3 to 10 mg/L. Arsenic provokes synchronous increases in cell death rate and intracellular levels of ROS and Ca2+ in V. faba guard cells. The typical nuclear morphological changes including nuclear fragmentation and nuclear condensation were observed in As-treated guard cells, while Z-Asp-2,6-dichlorobenzoyloxymethylketone (Z-Asp-CH2-DCB), a specific inhibitor of mammalian caspases, significantly blocked As-induced cell death. The occurrence of characteristic features of programmed cell death (PCD) and the inhibitory effect of caspase inhibitor Z-Asp-CH2-DCB on As-induced cell death suggest the activation of a PCD pathway evoked by arsenic exposure. Application of antioxidant catalase significantly inhibited As-induced cell death, PCD-to-total-cells ratio and intracellular Ca2+ increase provoked by arsenic. A specific Ca2+ chelator ethylene glycol tetraacetic acid also significantly decreased the cell death caused by arsenic. These results clearly demonstrated that arsenic induced cell death associated with obvious increases in intracellular ROS and Ca2+ levels, in which ROS positively regulated intracellular Ca2+ level.ROS generation and intracellular Ca2+ level increase in As-treated stomatal guard cells were involved in the process of As-induced cell death. The results of the present study indicate that arsenite induced guard cell death via a PCD pathway through ROS mediating Ca2+ elevation. 参考文献 相似文献 引证文献

Neuroglobin Involvement in the Course of Arsenic Toxicity in Rat Cerebellar Granule Neurons

Exposure to arsenic in drinking water results in a widespread environmental problem in the world, and the brain is a major target. Neuroglobin is a vertebrate heme protein regarded as playing neuroprotective role in hypoxia or oxidative stress. In this study, we investigated the toxic effects of sodium arsenite (NaAsO2) on primary cultured rat cerebellar granule neurons (CGNs) and detected neuroglobin (Ngb) expression in rat CGNs exposed to NaAsO2. Our results show that apoptosis was obviously induced by NaAsO2 treatment in rat CGNs by annexin V-fluorescein isothiocyanate assay. Intracellular reactive oxygen species generation increased significantly in the cells exposed to NaAsO2, and the apoptotic effects could be partially reversed by antioxidant N-acetyl-L-cysteine. Ngb protein and mRNA expression were significantly downregulated in rat CGNs shortly after NaAsO2 exposure and then upregulated after a longer time of exposure. Furthermore, mRNA expression changed more than protein expression and the toxic effect of NaAsO2 on Ngb expression is dose dependent. Higher Ngb expression was also detected in rat cerebellum, but not in other parts (cerebrum, hippocampus, and midbrain) of the brain exposed to NaAsO2 for 16weeks. Taken together, cytotoxic effects of NaAsO2 on rat CGNs is induced at least partly by oxidative stress and Ngb may influence the course of arsenic toxicity in rat CGNs and rat cerebellum.

Protective effects of selenium on oxidative damage and oxidative stress related gene expression in rat liver under chronic poisoning of arsenic

Arsenic (As) is a toxic metalloid existing widely in the environment, and chronic exposure to it through contaminated drinking water has become a global problem of public health. The present study focused on the protective effects of selenium on oxidative damage of chronic arsenic poisoning in rat liver. Rats were divided into four groups at random and given designed treatments for 20 weeks. The oxidative damage of liver tissue was evaluated by lipid peroxidation and antioxidant enzymes. Oxidative stress related genes were detected to reflect the liver stress state at the molecular level. Compared to the control and Na2SeO3 groups, the MDA content in liver tissue was decreased and the activities of antioxidant enzymes were increased in the Na2SeO3 intervention group. The mRNA levels of SOD1, CAT, GPx and Txnrd1 were increased significantly (P<0.05) in the combined Na2SeO3+NaAsO2 treatment group. The expressions of HSP70 and HO-1 were significantly (P<0.05) increased in the NaAsO2 group and reduced in the combined treatment group. The results indicate that long-term intake of NaAsO2 causes oxidative damage in the rat liver, and Na2SeO3 protects liver cells by adjusting the expression of oxidative stress related genes to improve the activities of antioxidant enzymes.

Sodium arsenite dependent protein expression analysis on human embryonic carcinoma (NCCIT) cell line

Due to their pluripotent nature, embryonic carcinoma (EC) cell lines are useful for the study of basic and applied aspects of medical therapeutics, disease management and environmental mutagenesis. We evaluated the teratogenic like effects of inorganic arsenic during the early stages of cellular development in NCCIT cells, a type of human EC cells. Using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and MetaCore pathway analysis software (GeneGo), the proteomic expression profiles of NCCIT cells after either short- or long-term sodium arsenite (NaAsO2) treatment and of NCCIT cell-derived embryoid bodies (EBs) after short-term NaAsO2 treatment were studied to determine the toxic effects on the process of normal growth and differentiation. The protein expression profiles of the NaAsO2-treated NCCIT cells and EBs were compared with that of untreated NCCIT cells. Short-term NaAsO2 treatment resulted in the down-regulation of most proteins, with heat shock 90-kDa protein (HSP90) and valosin-containing protein (VCP) being significantly downregulated. Long-term NaAsO2 treatment caused marked up-regulation of B23/nucleophosmin, glucose regulated protein 78-kDa (GRP78), unc-51-like kinase 3 (ULK3), toll-like receptor 6 precursor (TLR6) and mitogen-activated protein kinase 7 isoform A (MAP3K7). NaAsO2 treatment of the NCCIT cell-derived EBs resulted in the down-regulation of several tumor-suppressor proteins. Taken together, these data suggest that a wide spectrum of cellular responses is induced to cope with chronic non-lethal toxic stresses in NCCIT cells.

Arsenite-Induced Apoptosis Is Prevented by Selenite in A375 Cell Line

Arsenic trioxide induces apoptosis and clinical remission in patients diagnosed with acute promyelocytic leukemia. The human malignant melanoma A375 cells were treated with NaAsO2 (0.1–130 μM) and also treated with combined 10 μM NaAsO2 and 10 μM Na2SeO3. NaAsO2 arrested cell growth in the G1 phase and induced apoptosis in a concentration- and time-dependent manner. In contrast, administration of Na2SeO3 antagonized the cell growth inhibition and apoptosis induced by NaAsO2. The NaAsO2 treatment resulted in a marked increase in p53 protein as early as 4 h and in Bcl-2 protein level by 12 h. In addition, p53 downregulation accompanied the combined treatment of NaAsO2 and Na2SeO3. Thus, our results indicate upregulation of p53 and Bcl-2 play acrucial role in the NaAsO2-induced G1 arrest and apoptosis of A375 cells and that downregulation p53 appears to contribute to the inhibition by Na2SeO3 of the effects induced by NaAsO2.

Arsenic induces mitochondria-dependent apoptosis by reactive oxygen species generation rather than glutathione depletion in Chang human hepatocytes

This study was conducted to evaluate the possible involvement of mitochondrial pathway in NaAsO2-induced apoptosis and the role of reactive oxygen species (ROS) and reduced glutathione (GSH) in the apoptotic effect in Chang human hepatocytes. The MTT assay demonstrated that sodium arsenite (NaAsO2) treatment for 24 h caused a dose-dependent decrease of cell viability. NaAsO2 treatment (0-30 microM) was also found to induce phosphatidylserine externalization, a hallmark of apoptosis; to disrupt the mitochondrial membrane potential (Deltapsi ( m )); to cause the release of cytochrome c into the cytosol, and to trigger cleavage of caspase-3 and poly (ADP-ribose) polymerase (PARP) in a dose-dependent manner. All these changes were accompanied with the enhanced generation of intracellular ROS and malondialdehyde (MDA). Increase of intracellular GSH also coincided unexpectedly. Moreover, the extracellular addition of N-acetyl-L-cysteine (NAC, 5 mM) effectively reduced the generation of ROS and MDA, and rescued the cells from NaAsO2 induced apoptosis and related alteration of mitochondria. These data suggest that the arsenic-induced cell apoptosis occurs though the mitochondrial pathway, and is mostly dependent on generation of ROS rather than GSH depletion in Chang human hepatocytes.