Zc. Heng et al., INDUCTION OF CHROMOSOMAL-ABERRATIONS BY 2,4-DICHLORO-6-AMINOPHENOL INCULTURED V79 CELLS, Teratogenesis, carcinogenesis, and mutagenesis, 16(2), 1996, pp. 81-87
2,4-Dichloro-6-aminophenol (DCAP) is a major metabolite of the herbici
de 2,4-dichloro-6-nitrophenol ammonium (DCNPA). In our previous studie
s this metabolite, but not the parent compound, was found to induce si
ster chromatid exchanges (SCEs) and micronucleus (MN) formation in Chi
nese hamster lung fibroblasts (V79 cells). Further studies were carrie
d out to determine whether DCAP can also induce structural chromosomal
aberrations (CAs) in cultured V79 cells. The assay was performed unde
r three different treatment conditions: 1) 3 h treatment followed by 1
7 h post-treatment incubation, 2) 12 h treatment, and 3) 20 h treatmen
t with multiple sampling times. Results showed that CAs were induced b
y DCAP in V79 cells. The aberrations were mainly chromatid types (gaps
, breaks, and deletions), triradials, quadriradials, and complex rearr
angements. However, induction of CAs appears to be dependent on the tr
eatment condition. The 3 h treatment following a 17 h posttreatment in
cubation gave rise to 24% aberrant cells (excluding gaps) and a total
of 44 aberrations per 100 metaphases, while the 12 h treatment only ga
ve a borderline response and the 20 h treatment did not yield a signif
icant increase of CAs at any concentration tested. It seems that a sho
rt-term treatment with higher concentrations is a better treatment pro
tocol for genotoxicity studies of certain cytotoxic chemicals such as
DCAP. Results of this study further indicate that the herbicide DCNPA
is potentially hazardous to the exposed population. (C) 1996 Wiley-Lis
s, Inc.