Huang X, Frenkel K, Klein C B, Costa M
New York University Medical Center, Nelson Institute of Environmental Medicine, New York 10016.
Toxicol Appl Pharmacol. 1993 May;120(1):29-36. doi: 10.1006/taap.1993.1083.
Exposure of intact cultured Chinese hamster ovary (CHO) cells to water-soluble nickel (Ni) salts and to relatively water-insoluble crystalline nickel subsulfide (Ni3S2) resulted in an increased formation of the fluorescent oxidized compound, dichlorofluorescein (DCF) from the parent nonfluorescent compound, 2,7-dichlorofluorescin diacetate. This fluorescent product was also formed in vitro following oxidation with relatively strong oxidants such as hydrogen peroxide in the presence of peroxidase, suggesting that Ni increased the concentration of hydrogen peroxide in intact cells. However, formation of other strong oxidants such as hydroperoxides is possible since they have also been shown to cause the oxidation of the nonfluorescent dichlorofluorescin to the fluorescent product DCF in vitro. Localization of the oxidized fluorescent DCF in intact cells was also examined by fluorescence microscopy. Both Ni3S2 and NiCl2 appeared to increase the degree of fluorescence in intact CHO cells around the nuclear membranes. This increase in fluorescence was greater in the presence of relatively water-insoluble Ni3S2 than water-soluble NiCl2. These results add to the emerging concept that Ni-induced genotoxicity may be mediated by oxygen radical intermediates.
将完整的培养中国仓鼠卵巢（CHO）细胞暴露于水溶性镍盐和相对水不溶性的结晶硫化镍（Ni3S2）中，会导致荧光氧化产物二氯荧光素（DCF）从母体非荧光化合物2,7 - 二氯荧光素二乙酸酯的形成增加。在过氧化物酶存在的情况下，用相对较强的氧化剂如过氧化氢进行体外氧化时，也会形成这种荧光产物，这表明镍增加了完整细胞中过氧化氢的浓度。然而，其他强氧化剂如氢过氧化物的形成也是可能的，因为它们在体外也已被证明可导致非荧光二氯荧光素氧化为荧光产物DCF。还通过荧光显微镜检查了完整细胞中氧化荧光DCF的定位。Ni3S2和NiCl2似乎都增加了完整CHO细胞核膜周围细胞的荧光程度。在相对水不溶性的Ni3S2存在下，这种荧光增加比水溶性的NiCl2更大。这些结果进一步支持了镍诱导的遗传毒性可能由氧自由基中间体介导这一新兴概念。
