M'Bemba-Meka Prosper, Lemieux Nicole, Chakrabarti Saroj K
Human Toxicology Research Group, TOXHUM, Department of Environmental and Occupational Health, Faculty of Medicine, Université de Montréal, Main Station , P.O. Box 6128, H3C 3J7, Montréal, QC, Canada.
Arch Toxicol. 2006 Jul;80(7):405-20. doi: 10.1007/s00204-006-0060-x. Epub 2006 Apr 26.
When isolated human lymphocytes were treated in vitro with various concentrations of soluble form of nickel carbonate hydroxide (NiCH) (0-1 mM), at 37 degrees C for 4 h, both concentration- and time-dependent effects of NiCH on lymphocyte death were observed. Increased generation of hydrogen peroxide (H(2)O(2)), superoxide anion (O(2)(-) ), depletion of both no protein (NP-) and protein (P-) sulfhydryl (SH) contents and lipid peroxidation (LPO) were induced by NiCH. Pretreatment of lymphocytes with either catalase (H(2)O(2) scavenger), or deferoxamine (DFO) (iron chelator), or excess glutathione (GSH) (an antioxidant) not only significantly reduced the NiCH-induced generation of H(2)O(2) and LPO, but also increased the NP-SH and P-SH contents initially reduced by NiCH. NiCH-induced generation of excess O(2)(-) but not excess LPO was significantly reduced by pretreatment with superoxide dismutase (SOD). NiCH-induced lymphocyte death was significantly prevented by pre-treatment with either catalase, or dimethylthiourea/mannitol (hydroxyl radical scavengers), or DFO, or excess GSH/N-acetylcysteine. NiCH-induced lymphocyte death was also significantly prevented by pretreatment with excess SOD. Thus, various types of oxidative stresses play an important role in NiCH-induced lymphocyte death. Cotreatment with cyclosporin A (a specific inhibitor of alteration in mitochondrial membrane potential (DeltaPsi(m)) not only inhibited NiCH-induced alteration in DeltaPsi(m), but also significantly prevented Ni-compound-induced lymphocyte death. Furthermore, NiCH-induced destabilization of cellular calcium homeostasis. As such, NiCH-induced lymphocyte death was significantly prevented by modulating intracellular calcium fluxes such as Ca(2+) channel blockers and intracellular Ca(2+) antagonist. Thus, the mechanism of NiCH (soluble form)-induced activation of lymphocyte death signalling pathways involves not only the excess generation of different types of oxidative stress, but also the induction of alteration in DeltaPsi(m) and destabilization of cellular calcium homeostasis as well.
当分离出的人淋巴细胞在体外与不同浓度（0 - 1 mM）的氢氧化镍碳酸盐可溶形式（NiCH）于37℃处理4小时时，观察到NiCH对淋巴细胞死亡具有浓度和时间依赖性效应。NiCH可诱导过氧化氢（H₂O₂）、超氧阴离子（O₂⁻）生成增加，非蛋白质（NP - ）和蛋白质（P - ）巯基（SH）含量耗竭以及脂质过氧化（LPO）。用过氧化氢酶（H₂O₂清除剂）、去铁胺（DFO）（铁螯合剂）或过量谷胱甘肽（GSH）（抗氧化剂）对淋巴细胞进行预处理，不仅能显著减少NiCH诱导的H₂O₂生成和LPO，还能增加最初因NiCH而降低的NP - SH和P - SH含量。用超氧化物歧化酶（SOD）预处理可显著减少NiCH诱导的过量O₂⁻生成，但不能减少过量LPO生成。用过氧化氢酶、二甲基硫脲/甘露醇（羟基自由基清除剂）、DFO或过量GSH/N - 乙酰半胱氨酸进行预处理可显著预防NiCH诱导的淋巴细胞死亡。用过量SOD进行预处理也可显著预防NiCH诱导的淋巴细胞死亡。因此，各种类型的氧化应激在NiCH诱导的淋巴细胞死亡中起重要作用。与环孢素A（线粒体膜电位（ΔΨm）改变的特异性抑制剂）共同处理不仅能抑制NiCH诱导的ΔΨm改变，还能显著预防镍化合物诱导的淋巴细胞死亡。此外，NiCH可导致细胞钙稳态失衡。因此，通过调节细胞内钙通量，如钙通道阻滞剂和细胞内钙拮抗剂，可显著预防NiCH诱导的淋巴细胞死亡。因此，NiCH（可溶形式）诱导淋巴细胞死亡信号通路激活的机制不仅涉及不同类型氧化应激的过量生成，还涉及ΔΨm改变的诱导以及细胞钙稳态失衡。
