title: The chlorophenoxy herbicide dicamba and its commercial formulation banvel induce genotoxicity and cytotoxicity in Chinese hamster ovary (CHO) cells.
abstract: The sister chromatid exchange (SCE) frequency, the cell-cycle progression analysis, and the single cell gel electrophoresis technique (SCGE, comet assay) were employed as genetic end-points to investigate the geno- and citotoxicity exerted by dicamba and one of its commercial formulation banvel (dicamba 57.71%) on Chinese hamster ovary (CHO) cells. Log-phase cells were treated with 1.0-500.0 microg/ml of the herbicides and harvested 24 h later for SCE and cell-cycle progression analyses. All concentrations assessed of both test compounds induced higher SCE frequencies over control values. SCEs increased in a non-dose-dependent manner neither for the pure compound (r=0.48; P>0.05) nor for the commercial formulation (r=0.58, P>0.05). For the 200.0 microg/ml and 500.0 microg/ml dicamba doses and the 500.0 microg/ml banvel dose, a significant delay in the cell-cycle progression was found. A regression test showed that the proliferation rate index decreased as a function of either the concentration of dicamba (r=-0.98, P<0.05) or banvel (r=-0.88, P<0.01) titrated into cultures in the 1.0-500.0 microg/ml dose-range. SCGE performed on CHO cells after a 90 min pulse-treatment of dicamba and banvel within a 50.0-500.0 microg/ml dose-range revealed a clear increase in dicamba-induced DNA damage as an enhancement of the proportion of slightly damaged and damaged cells for all concentrations used (P<0.01); concomitantly, a decrease of undamaged cells was found over control values (P<0.01). In banvel-treated cells, a similar overall result was registered. Dicamba induced a significant increase both in comet length and width over control values (P<0.01) regardless of its concentration whereas banvel induced the same effect only within 100.0-500.0 microg/ml dose range (P<0.01). As detected by three highly sensitive bioassays, the present results clearly showed the capability of dicamba and banvel to induce DNA and cellular damage on CHO cells.
authors.affiliation: Cátedra de Citología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina.
authors.forename: Norma V
authors.initials: NV
authors.lastname: González
authors.forename: Sonia
authors.initials: S
authors.lastname: Soloneski
authors.forename: Marcelo L
authors.initials: ML
authors.lastname: Larramendy
mesh_terms: D000818:Animals; D016466:CHO Cells; D002453:Cell Cycle; D020552:Comet Assay; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D003996:Dicamba / Q000031:analogs & derivatives* / Q000633:toxicity*; D006540:Herbicides / Q000633:toxicity*; D009152:Mutagenicity Tests; D012854:Sister Chromatid Exchange
chemical_list: D006540:Herbicides; C027233:dicamba dimethylamine; D003996:Dicamba