Twerdok L E, Trush M A
Department of Environmental Health Sciences, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, MD 21205.
Chem Biol Interact. 1988;65(3):261-73. doi: 10.1016/0009-2797(88)90111-1.
Neutrophil-derived oxidants have been implicated in both damage to biomolecules and the metabolic activation of xenobiotics. Since the bone marrow is a relatively neutrophil-rich tissue which is subject to xenobiotic toxicity, we have characterized the oxidant generating capability of neutrophilic cells isolated from femurs of male C57BL/6J mice. Addition of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) to neutrophil preparations (70 +/- 5% ring neutrophils and metamyelocytes) elicited superoxide anion generation, as indicated by superoxide dismutase (SOD)-inhibitable acetylated cytochrome c reduction, and oxidant-dependent chemiluminescence (CL) from luminol or lucigenin. The interaction of benzo[a]pyrene-7,8-dihydrodiol (BP-diol), a proximate carcinogenic metabolite of benzo[a]pyrene (BP), with TPA-stimulated bone marrow neutrophils resulted in azide-inhibitable CL (90%) indicative of its myeloperoxidase-dependent oxidation to an excited-state intermediate. Covalent binding of [3H]BP-diol to exogenous DNA was similarly increased 3-fold in the presence of TPA-stimulated bone marrow neutrophils. Recently, our laboratory has shown that in addition to CL, TPA-stimulated human polymorphonuclear leukocytes can activate BP-diol to an intermediate which covalently binds to DNA and elicits mutagenicity in Salmonella typhimurium TA100. These observations combined with our current results suggest a possible role for neutrophil-derived oxidants in the mechanisms of chemically-induced bone marrow toxicity.
中性粒细胞衍生的氧化剂与生物分子损伤及外源性物质的代谢活化均有关联。由于骨髓是一个富含中性粒细胞且易受外源性物质毒性影响的组织，我们对从雄性C57BL/6J小鼠股骨中分离出的嗜中性细胞产生氧化剂的能力进行了表征。向中性粒细胞制剂（70±5%的环状中性粒细胞和晚幼粒细胞）中添加佛波酯12-O-十四酰佛波醇-13-乙酸酯（TPA）会引发超氧阴离子的产生，超氧化物歧化酶（SOD）可抑制的乙酰化细胞色素c还原以及鲁米诺或光泽精产生的依赖氧化剂的化学发光（CL）表明了这一点。苯并[a]芘的近致癌物代谢物苯并[a]芘-7,8-二氢二醇（BP-二醇）与TPA刺激的骨髓中性粒细胞相互作用，会导致叠氮化物抑制的CL（90%），这表明其通过髓过氧化物酶依赖性氧化形成激发态中间体。在TPA刺激的骨髓中性粒细胞存在的情况下，[3H]BP-二醇与外源DNA的共价结合同样增加了3倍。最近，我们实验室表明，除了CL外，TPA刺激的人类多形核白细胞还可将BP-二醇激活为一种中间体，该中间体与DNA共价结合并在鼠伤寒沙门氏菌TA100中引发致突变性。这些观察结果与我们目前的结果相结合，提示中性粒细胞衍生的氧化剂在化学诱导的骨髓毒性机制中可能发挥作用。
