Zordan M, Russo A, Costa R, Bianco N, Beltrame C, Levis A G
Department of Biology, University of Padova, Italy.
Environ Mol Mutagen. 1990;15(4):205-13. doi: 10.1002/em.2850150406.
The genetic effects of nitrilotriacetic acid (NTA) and ethylenedinitrilotetraacetic acid (EDTA), two widely used chelating agents, were investigated by using a somatic mutation and recombination test (SMART) after treatment of larvae and the FIX test for aneuploidy after treatment of adult female Drosophila melanogaster. Chloral hydrate (CH) and 5-fluorodeoxyuridine (FdUr) were used as positive controls. Effectively absorbed amounts of the test compounds assayed in Drosophila were estimated at the single fly level by a method using 3H-leucine. NTA and EDTA were also assayed in tests for aneuploidy based on chromosome counting in mouse germ and somatic cells. We previously showed that NTA was able to induce aneuploidy (chromosomal gain) in the germ cells of both Drosophila and the mouse when tested at the exposure levels of 5 x 10(-2) M and 275 mg per kg body weight, respectively [Costa et al., Environ Mol Mutagen 12:397-407, 1988]. In the present experiments, EDTA was assayed at 2.5 x 10(-2) M and 7.5 x 10(-3) M in the FIX test adopting a three-stage brooding scheme. Significant increases (with respect to controls) in chromosomal loss were observed in the second brood and in the combined three-brood total for both exposure levels of EDTA. In the SMART test, treatments with EDTA in the same exposure range produced negative results over all end-points, whereas significant increases in the frequency of small single spots (possibly due to aneuploidy) were produced by NTA 5 x 10(-2) M. In the cytogenetic assays for aneuploidy both in the germ and somatic cells of the mouse, negative results were also obtained following the i.p. administration of 93 and 186 mg EDTA per kg b.w. The previously observed induction of germ cell aneuploidy by NTA (275 mg per kg b.w.) was confirmed in the present experiments on a different strain of mice. NTA (138-275 mg per kg b.w.) did not induce aneuploidy in somatic cells of the mouse [Russo et al., Mutat Res 226: 111-114, 1989], however. These results are compared and discussed with reference to the characteristics of the different test systems used and to the different chelating properties of NTA and EDTA.
通过对果蝇幼虫进行处理后使用体细胞突变和重组试验（SMART），以及对成年雌性黑腹果蝇进行处理后使用FIX非整倍体试验，研究了两种广泛使用的螯合剂次氮基三乙酸（NTA）和乙二胺四乙酸（EDTA）的遗传效应。水合氯醛（CH）和5-氟脱氧尿苷（FdUr）用作阳性对照。通过使用³H-亮氨酸的方法在单只果蝇水平上估计果蝇中所检测的受试化合物的有效吸收量。还基于小鼠生殖细胞和体细胞中的染色体计数，在非整倍体试验中对NTA和EDTA进行了检测。我们之前表明，当分别以5×10⁻²M和每千克体重275mg的暴露水平进行测试时，NTA能够在果蝇和小鼠的生殖细胞中诱导非整倍体（染色体增加）[科斯塔等人，《环境分子突变》12:397 - 407，1988年]。在本实验中，采用三阶段育雏方案，在FIX试验中以2.5×10⁻²M和7.5×10⁻³M的浓度对EDTA进行检测。在EDTA的两个暴露水平下，在第二窝以及三窝总和中均观察到染色体丢失相对于对照有显著增加。在SMART试验中，相同暴露范围内的EDTA处理在所有终点均产生阴性结果，而5×10⁻²M的NTA导致小单斑频率显著增加（可能由于非整倍体）。在小鼠生殖细胞和体细胞的非整倍体细胞遗传学检测中，腹腔注射每千克体重93mg和186mg的EDTA后也得到阴性结果。在本实验中，对不同品系的小鼠进行研究，证实了之前观察到的NTA（每千克体重275mg）诱导生殖细胞非整倍体的现象。然而，NTA（每千克体重138 - 275mg）并未在小鼠体细胞中诱导非整倍体[鲁索等人，《突变研究》226: 111 - 114，1989年]。参照所使用的不同测试系统的特性以及NTA和EDTA不同的螯合特性，对这些结果进行了比较和讨论。
