EFFECT OF LONG-TERM REMOVAL OF IRON FROM ASBESTOS BY DESFERRIOXAMINE-B ON SUBSEQUENT MOBILIZATION BY OTHER CHELATORS AND INDUCTION OF DNA SINGLE-STRAND BREAKS
EFFECT OF LONG-TERM REMOVAL OF IRON FROM ASBESTOS BY DESFERRIOXAMINE-B ON SUBSEQUENT MOBILIZATION BY OTHER CHELATORS AND INDUCTION OF DNA SINGLE-STRAND BREAKS
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DOI：
10.1006/abbi.1994.1009
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发表时间：
1994-01-01
影响因子：
3.9
通讯作者：
AUST, AE
中科院分区：
文献类型：
--
作者：
CHAO, CC;AUST, AE
研究了去铁胺B （DF）在pH为7.5或5.0条件下对青橄榄石和铁的长期去除效果。将Crocidolite或amoite （1 mg/ml）悬浮在pH为7.5或5.0的50 mM NaCl中，并添加1 mM DF，悬浮时间长达90天。虽然铁的动员率随着时间的推移而降低，但在pH 5.0或7.5时，铁从两种形式的石棉中连续地动员起来。在两种pH下，从青橄榄石中动员的铁量至少是从亚铁石中动员的两倍。在前15天，pH为5.0时铁从青橄榄石中动员的速度比pH为7.5时快，但在随后的时间里，pH为7.5时的动员量等于或略大于pH为5.0时的动员量。对于阿莫子石，pH 5.0时的动员量总是大于pH 7.5时的动员量。接下来，研究了DF去除石棉中的铁对随后第二螯合剂（EDTA或柠檬酸盐）的铁动员以及诱导DNA单链断裂（SSBs）的影响。石棉在pH 7.5下用DF处理15天，洗涤去除铁胺和多余的DF，然后用EDTA或柠檬酸盐（1 mM）孵育。随着越来越多的铁被DF去除，第二螯合剂从两种形式的石棉中动员铁的速率降低。DNA SSBs的诱导也减少了，这反映了铁无法催化损伤。研究结果表明了三点。首先，如果在体外观察到体内发生的石棉铁的长期动员，它可能在石棉的长期生物学效应中起作用。其次，当石棉纤维被细胞吞噬并维持在pH为4.0-5.0的吞噬体中时，可能会更快地从石棉纤维中动员铁。第三，在接触培养细胞或整只动物之前，用铁螯合剂（如DF）处理石棉，可能会减少铁对石棉造成的生物效应，但可能不会完全消除它们。
The long-term removal of iron from crocidolite or amosite by desferrioxamine B (DF) at pH 7.5 or 5.0 was studied. Crocidolite or amosite (1 mg/ml) was suspended in 50 mM NaCl at pH 7.5 or 5.0 with the addition of 1 mM DF for up to 90 days. Although the rate of iron mobilization decreased with time, iron was continuously mobilized from both forms of asbestos at pH 5.0 or 7.5. The amount of iron mobilized from crocidolite was at least twice that mobilized from amosite at either pH. Iron was mobilized more rapidly from crocidolite at pH 5.0 than at 7.5 for the first 15 days, but at later times the amount being mobilized at pH 7.5 became equal to or slightly greater than that at 5.0. For amosite, the mobilization at pH 5.0 was always greater than that at pH 7.5. Next, the effect of iron removal from asbestos by DF on subsequent iron mobilization by a second chelator (EDTA or citrate) and on induction of DNA single-strand breaks (SSBs) was studied. Asbestos, treated for up to 15 days with DF at pH 7.5, was washed to remove ferrioxamine and excess DF, then incubated with EDTA or citrate (1 mM). The rates of iron mobilization from both forms of asbestos by a second chelator decreased as more and more iron was removed by DF. Induction of DNA SSBs also decreased, reflecting the unavailability of iron to catalyze the damage. The results suggest three things. First, if long-term mobilization of iron from asbestos occursin vivoas has been observed in vitro, it may play a role in the long-term biological effects of asbestos. Second, more rapid mobilization of iron from asbestos fibers may occur when the fibers are phagocytized by cells and maintained in phagosomes where the pH is 4.0-5.0. Third, treatment of asbestos by iron chelators, such as DF, prior to exposure to cultured cells or whole animals, may reduce the biological effects of asbestos resulting from iron, but may not completely eliminate them.