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Calabrese EJ, Selby PB. Comet assay and hormesis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122929. [PMID: 37979647 DOI: 10.1016/j.envpol.2023.122929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/06/2023] [Accepted: 11/11/2023] [Indexed: 11/20/2023]
Abstract
The paper provides the first assessment of the occurrence of hormetic dose responses using the Comet assay, a genotoxic assay. Using a priori evaluative criteria based on the Hormetic Database on peer-reviewed comet assay experimental findings, numerous examples of hormetic dose responses were obtained. These responses occurred in a large and diverse range of cell types and for agents from a broad range of chemical classes. Limited attempts were made to estimate the frequency of hormesis within comet assay experimental studies using a priori entry and evaluative criteria, with results suggesting a frequency in the 40% range. These findings are important as they show that a wide range of genotoxic chemicals display evidence that is strongly suggestive of hormetic dose responses. These findings have significant implications for study design issues, including the number of doses selected, dose range and spacing. Likewise, the widespread occurrence of hormetic dose responses in this genotoxic assay has important risk assessment implications.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.
| | - Paul B Selby
- Retired from Oak Ridge National Laboratory at Oak Ridge, TN. Home Address: 4088 Nottinghill Gate Road, Upper Arlington, OH, 43220, USA.
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2
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Lima TRR, Martins AC, Pereira LC, Aschner M. Toxic Effects Induced by Diuron and Its Metabolites in Caenorhabditis elegans. Neurotox Res 2022; 40:1812-1823. [PMID: 36306114 DOI: 10.1007/s12640-022-00596-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/26/2022] [Accepted: 10/18/2022] [Indexed: 01/18/2023]
Abstract
The toxicity of diuron herbicide and its metabolites has been extensively investigated; however, their precise toxic mechanisms have yet to be fully appreciated. In this context, we evaluated the toxic mechanism of diuron, 3,4-dichloroaniline (DCA) and 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU), using Caenorhabditis elegans (C. elegans) in the L1 larval stage. For this purpose, worms were acutely exposed to the test chemicals with a preliminary concentration range of 0.5 to 500 μM and first analyzed for lethality (%). Next, the highest concentration (500 μM) was considered for survival (%), reactive oxygen and nitrogen species (RONS), glutathione (GSH) and ATP levels, autophagy index, behavior, and dopaminergic neurodegeneration parameters. Interestingly, increased lethality (%) was found for all chemicals at the higher concentrations tested (100 and 500 μM), with significant differences at 500 μM DCA (p < 0.05). A decrease in the median survival was observed mainly for DCA. Although no changes were observed in RONS production, GSH levels were significantly increased upon diuron and DCA treatment, likely reflecting an attempt to restore the redox status. Moreover, diuron and its metabolites impaired ATP levels, suggesting an alteration in mitochondrial function. The latter may trigger autophagy as an adaptive survival mechanism, but this was not observed in C. elegans. Dopaminergic neurotoxicity was observed upon treatment with all the tested chemicals, but only diuron induced alterations in the worms' locomotor behavior. Combined, these results indicate that exposure to high concentrations of diuron and its metabolites elicit distinct adverse outcomes in C. elegans, and DCA in particular, plays an important role in the overall toxicity observed in this experimental model.
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Affiliation(s)
- Thania Rios Rossi Lima
- Medical School - TOXICAM, UNIPEX, São Paulo State University (Unesp), Block 5 Botucatu, São Paulo, 18618-970, Brazil. .,Center for Evaluation of Environmental Impact On Human Health (TOXICAM), Medical School, Unesp, Botucatu, SP, Brazil.
| | - Airton C Martins
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Lílian Cristina Pereira
- Center for Evaluation of Environmental Impact On Human Health (TOXICAM), Medical School, Unesp, Botucatu, SP, Brazil.,School of Agriculture, São Paulo State University (Unesp), Botucatu, SP, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
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Lima TRR, de Oliveira Lima E, Delafiori J, Ramos Catharino R, Viana de Camargo JL, Pereira LC. Molecular signatures associated with diuron exposure on rat urothelial mitochondria. Toxicol Mech Methods 2022; 32:628-635. [PMID: 35379061 DOI: 10.1080/15376516.2022.2062271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Diuron, 3- (3,4-dichlorophenyl)-1,1-dimethylurea, is a worldwide used herbicide whose biotransformation gives rise to the metabolites, 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and 3,4-dichloroaniline (DCA). Previous studies indicate that diuron and/or its metabolites are toxic to the bladder urothelium of the Wistar rats where, under certain conditions of exposure, they may induce successively urothelial cell degeneration, necrosis, hyperplasia and eventually tumors. The hypothesis was raised that the molecular initiating event (MIE) of this Adverse Outcome Pathway (AOP) is the mitochondrial toxicity of those compounds. Therefore, this study aimed to investigate in vitro the metabolic alterations resulting from urothelial mitochondria isolated from male Wistar rats exposure to diuron, DCPMU and DCA at 10 and 100 µM. A non-targeted metabolomic analysis using mass spectrometry showed discriminative clustering among groups and alterations in the intensity abundance of membrane-associated molecules phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylserine (PS), in addition to methylhexanoyl-CoA and, particularly for diuron 100 µM, dehydro-L-gulonate, all of them involved in critical mitochondrial metabolism. Collectively, these data indicate the mitochondrial dysfunction as a MIE that triggers cellular damage and death observed in previous studies.
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Affiliation(s)
- Thania Rios Rossi Lima
- São Paulo State University (Unesp), Medical School, Botucatu.,Center for Evaluation of Environmental Impact on Human Health (TOXICAM), Unesp, Medical School, Botucatu
| | | | - Jeany Delafiori
- Innovare Biomarkers Laboratory, School of Pharmaceutical Sciences, University of Campinas (UNICAMP), Campinas
| | - Rodrigo Ramos Catharino
- Innovare Biomarkers Laboratory, School of Pharmaceutical Sciences, University of Campinas (UNICAMP), Campinas
| | - João Lauro Viana de Camargo
- São Paulo State University (Unesp), Medical School, Botucatu.,Center for Evaluation of Environmental Impact on Human Health (TOXICAM), Unesp, Medical School, Botucatu
| | - Lílian Cristina Pereira
- São Paulo State University (Unesp), Medical School, Botucatu.,São Paulo State University (Unesp), School of Agriculture, Botucatu.,Center for Evaluation of Environmental Impact on Human Health (TOXICAM), Unesp, Medical School, Botucatu
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Peraza-Vega RI, Castañeda-Sortibrán AN, Valverde M, Rojas E, Rodríguez-Arnaiz R. Assessing genotoxicity of diuron on Drosophila melanogaster by the wing-spot test and the wing imaginal disk comet assay. Toxicol Ind Health 2016; 33:443-453. [PMID: 27777339 DOI: 10.1177/0748233716670536] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The aim of this study was to evaluate the genotoxicity of the herbicide diuron in the wing-spot test and a novel wing imaginal disk comet assay in Drosophila melanogaster. The wing-spot test was performed with standard (ST) and high-bioactivation (HB) crosses after providing chronic 48 h treatment to third instar larvae. A positive dose-response effect was observed in both crosses, but statistically reduced spot frequencies were registered for the HB cross compared with the ST. This latter finding suggests that metabolism differences play an important role in the genotoxic effect of diuron. To verify diuron's ability to produce DNA damage, a wing imaginal disk comet assay was performed after providing 24 h diuron treatment to ST and HB third instar larvae. DNA damage induced by the herbicide had a significantly positive dose-response effect even at very low concentrations in both strains. However, as noted for the wing-spot test, a significant difference between strains was not observed that could be related to the duration of exposure between both assays. A positive correlation between the comet assay and the wing-spot test was found with regard to diuron genotoxicity.
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Affiliation(s)
- Ricardo I Peraza-Vega
- 1 Faculty of Sciences, National Autonomous University of Mexico, Distrito Federal, Mexico
| | | | - Mahara Valverde
- 2 Institute of Biomedical Investigations, National Autonomous University of Mexico, Distrito Federal, Mexico
| | - Emilio Rojas
- 2 Institute of Biomedical Investigations, National Autonomous University of Mexico, Distrito Federal, Mexico
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Grassi TF, Tararam CA, Spinardi-Barbisan ALT, Domingues MAC, de Camargo JLV, Barbisan LF. Diuron Lacks Promoting Potential in a Rat Liver Bioassay. Toxicol Pathol 2016; 35:897-903. [DOI: 10.1080/01926230701748040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The promoting activity of the herbicide Diuron was evaluated in a medium-term rat liver carcinogenesis bioassay that uses as endpoint immunohistochemically identified glutathione S-transferase positive (GST-P+) foci. Male Wistar rats were allocated to the following groups: G1 to G6 were initiated for liver carcinogenesis by a single dose of diethylnitrosamine (DEN, 200 mg/kg) while groups G7 and G8 received only 0.9% NaCl (DEN vehicle). From the 2nd week animals were fed a basal diet (G1 and G7) or a diet added with Diuron at 125, 500, 1250, 2500 and 2500 ppm (G2 to G5 and G8, respectively) or 200 ppm Hexaclorobenzene (HCB; G6). The animals were submitted to 70% partial hepatectomy at the 3rd week and sacrificed at the 8th week. The herbicide did not alter ALT or creatinine serum levels. No conspicuous GST-P+ foci development was registered in non-initiated rats fed Diuron at 2500 ppm. While DEN-initiated animals fed Diuron at 1250 or 2500 ppm developed mild centrilobular hypertrophy, DEN-initiated HCB-fed animals showed severe liver centrilobular hypertrophy and significant GST-P+ foci development. These findings indicate that the medium-term assay adopted in this study does not reveal any liver carcinogenesis initiating or promoting potential of Diuron in the rat.
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Affiliation(s)
- Tony Fernando Grassi
- UNESP São Paulo State University, School of Medicine, Department of Pathology, Botucatu, 18618-000, SP, Brazil
| | - Cibele Aparecida Tararam
- UNESP São Paulo State University, School of Medicine, Department of Pathology, Botucatu, 18618-000, SP, Brazil
| | | | | | - João Lauro Viana de Camargo
- UNESP São Paulo State University, School of Medicine, Department of Pathology, Botucatu, 18618-000, SP, Brazil
| | - Luís Fernando Barbisan
- UNESP São Paulo State University, Institute of Biosciences, Department of Morphology, Botucatu, 18618-000, SP, Brazil
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Toxicity of diuron in human cancer cells. Toxicol In Vitro 2015; 29:1577-86. [DOI: 10.1016/j.tiv.2015.06.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/12/2015] [Accepted: 06/13/2015] [Indexed: 12/26/2022]
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Evaluation of early changes induced by diuron in the rat urinary bladder using different processing methods for scanning electron microscopy. Toxicology 2015; 333:100-106. [DOI: 10.1016/j.tox.2015.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 04/01/2015] [Accepted: 04/14/2015] [Indexed: 12/18/2022]
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8
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Ihlaseh-Catalano SM, Bailey KA, Cardoso APF, Ren H, Fry RC, Camargo JLV, Wolf DC. Dose and temporal effects on gene expression profiles of urothelial cells from rats exposed to diuron. Toxicology 2014; 325:21-30. [DOI: 10.1016/j.tox.2014.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/14/2014] [Accepted: 08/19/2014] [Indexed: 01/08/2023]
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Da Rocha MS, Arnold LL, De Oliveira MLCS, Catalano SMI, Cardoso APF, Pontes MGN, Ferrucio B, Dodmane PR, Cohen SM, De Camargo JLV. Diuron-induced rat urinary bladder carcinogenesis: Mode of action and human relevance evaluations using the International Programme on Chemical Safety framework. Crit Rev Toxicol 2014; 44:393-406. [DOI: 10.3109/10408444.2013.877870] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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10
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Ament Z, Waterman CL, West JA, Waterfield C, Currie RA, Wright J, Griffin JL. A metabolomics investigation of non-genotoxic carcinogenicity in the rat. J Proteome Res 2013; 12:5775-90. [PMID: 24161236 DOI: 10.1021/pr4007766] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Non-genotoxic carcinogens (NGCs) promote tumor growth by altering gene expression, which ultimately leads to cancer without directly causing a change in DNA sequence. As a result NGCs are not detected in mutagenesis assays. While there are proposed biomarkers of carcinogenic potential, the definitive identification of non-genotoxic carcinogens still rests with the rat and mouse long-term bioassay. Such assays are expensive and time-consuming and require a large number of animals, and their relevance to human health risk assessments is debatable. Metabolomics and lipidomics in combination with pathology and clinical chemistry were used to profile perturbations produced by 10 compounds that represented a range of rat non-genotoxic hepatocarcinogens (NGC), non-genotoxic non-hepatocarcinogens (non-NGC), and a genotoxic hepatocarcinogen. Each compound was administered at its maximum tolerated dose level for 7, 28, and 91 days to male Fisher 344 rats. Changes in liver metabolite concentration differentiated the treated groups across different time points. The most significant differences were driven by pharmacological mode of action, specifically by the peroxisome proliferator activated receptor alpha (PPAR-α) agonists. Despite these dominant effects, good predictions could be made when differentiating NGCs from non-NGCs. Predictive ability measured by leave one out cross validation was 87% and 77% after 28 days of dosing for NGCs and non-NGCs, respectively. Among the discriminatory metabolites we identified free fatty acids, phospholipids, and triacylglycerols, as well as precursors of eicosanoid and the products of reactive oxygen species linked to processes of inflammation, proliferation, and oxidative stress. Thus, metabolic profiling is able to identify changes due to the pharmacological mode of action of xenobiotics and contribute to early screening for non-genotoxic potential.
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Affiliation(s)
- Zsuzsanna Ament
- Medical Research Council Human Nutrition Research (MRC HNR), Elsie Widdowson Laboratory , 120 Fulbourn Road, Cambridge CB1 9NL, U.K. , The Department of Biochemistry, University of Cambridge , 80 Tennis Court Road, Cambridge CB2 1GA, U.K. , and Cambridge Systems Biology Centre (CSBC), University of Cambridge , Cambridge CB2 1QR, U.K
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Da Rocha MS, Arnold LL, Dodmane PR, Pennington KL, Qiu F, De Camargo JLV, Cohen SM. Diuron metabolites and urothelial cytotoxicity: in vivo, in vitro and molecular approaches. Toxicology 2013; 314:238-46. [PMID: 24172598 DOI: 10.1016/j.tox.2013.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/08/2013] [Accepted: 10/18/2013] [Indexed: 10/26/2022]
Abstract
Diuron is carcinogenic to the rat urinary bladder at high dietary levels. The proposed mode of action (MOA) for diuron is urothelial cytotoxicity and necrosis followed by regenerative urothelial hyperplasia. Diuron-induced urothelial cytotoxicity is not due to urinary solids. Diuron is extensively metabolized, and in rats, N-(3,4-dichlorophenyl)urea (DCPU) and 4,5-dichloro-2-hydroxyphenyl urea (2-OH-DCPU) were the predominant urinary metabolites; lesser metabolites included N-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and trace levels of 3,4-dichloroaniline (DCA). In humans, DCPMU and DCPU have been found in the urine after a case of product abuse. To aid in elucidating the MOA of diuron and to evaluate the metabolites that are responsible for the diuron toxicity in the bladder epithelium, we investigated the urinary concentrations of metabolites in male Wistar rats treated with 2500ppm of diuron, the urothelial cytotoxicity in vitro of the metabolites and their gene expression profiles. DCPU was found in rat urine at concentrations substantially greater than the in vitro IC50 and induced more gene expression alterations than the other metabolites tested. 2-OH-DCPU was present in urine at a concentration approximately half of the in vitro IC50, whereas DCPMU and DCA were present in urine at concentrations well below the IC50. For the diuron-induced MOA for the rat bladder, we suggest that DCPU is the primary metabolite responsible for the urothelial cytotoxicity with some contribution also by 2-OH-DCPU. This study supports a MOA for diuron-induced bladder effects in rats consisting of metabolism to DCPU (and 2-OH-DCPU to a lesser extent), concentration and excretion in urine, urothelial cytotoxicity, and regenerative proliferation.
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Affiliation(s)
- Mitscheli S Da Rocha
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA; Center for the Evaluation of the Environmental Impact on Human Health (TOXICAM), Department of Pathology, Botucatu Medical School, UNESP - São Paulo State University, Botucatu, São Paulo, Brazil.
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Dose–response of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] in the urothelial mucosa of Wistar rats. Toxicology 2013; 312:1-5. [DOI: 10.1016/j.tox.2013.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/02/2013] [Accepted: 07/10/2013] [Indexed: 11/17/2022]
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de Camargo JLV. Chemical carcinogenesis - mode of action to inform quantitative human risk. BMC Proc 2013; 7 Suppl 2:K10. [PMID: 24764467 PMCID: PMC3624635 DOI: 10.1186/1753-6561-7-s2-k10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- João Lauro V de Camargo
- Department of Pathology - Faculty of Medicine, São Paulo State University, UNESP, Botucatu, São Paulo, Brazil
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Da Rocha MS, Arnold LL, Pennington KL, Muirhead D, Dodmane PR, Anwar MM, Battalora M, De Camargo JLV, Cohen SM. Diuron-Induced Rat Bladder Epithelial Cytotoxicity. Toxicol Sci 2012; 130:281-8. [DOI: 10.1093/toxsci/kfs256] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Barrett K, Jaward FM. A review of endosulfan, dichlorvos, diazinon, and diuron--pesticides used in Jamaica. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2012; 22:481-499. [PMID: 22720746 DOI: 10.1080/09603123.2012.667794] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The global agricultural sector is the primary user of pesticides, consuming more than three billion kilograms of pesticides annually. Although pesticides are beneficial in controlling the proliferation of pests, they have been associated with adverse human and ecological impacts. Approximately 87% of the annually imported pesticides in Jamaica are applied within agricultural or household settings. However, in Jamaica, the potential impact on humans, their property, and the environment is unknown, as the fate of many of the locally applied pesticides has not been established. This review discusses four pesticides extensively applied in agricultural practices in Jamaica - endosulfan, diazinon, diuron, and dichlorvos. The information presented is essential for the development of fate and transport models of these chemicals. Consequently, health and ecological impact assessments may be conducted from the generated models.
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Affiliation(s)
- Kayon Barrett
- Department of Environmental and Occupational Health, College of Public Health, University of South Florida, Tampa, FL, USA
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A comparison of cell-collecting methods for the Comet assay in urinary bladders of rats. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2012; 742:26-30. [DOI: 10.1016/j.mrgentox.2011.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 11/04/2011] [Accepted: 11/16/2011] [Indexed: 11/20/2022]
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Ihlaseh SM, Bailey KA, Hester SD, Jones C, Ren H, Cardoso APF, Oliveira MLCS, Wolf DC, de Camargo JLV. Transcriptional Profile of Diuron-Induced Toxicity on the Urinary Bladder of Male Wistar Rats to Inform Mode of Action. Toxicol Sci 2011; 122:330-8. [DOI: 10.1093/toxsci/kfr108] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Domingues A, Barbisan LF, Martins PR, Spinardi-Barbisan ALT. Diuron exposure induces systemic and organ-specific toxicity following acute and sub-chronic exposure in male Wistar rats. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2011; 31:387-396. [PMID: 21787709 DOI: 10.1016/j.etap.2011.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 01/10/2011] [Accepted: 01/24/2011] [Indexed: 05/31/2023]
Abstract
Diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] is a substitute urea herbicide widely used on agricultural crops with potential mutagenic, teratogenic, reproductive and carcinogenic effects. Nonetheless, its toxic potential on the immune system needs a detailed assessment. Thus, in order to evaluate the adverse effect of this herbicide on lymphohematopoietic organs and macrophage activity, male Wistar rats were orally treated with Diuron at 125, 1250 and 2500 ppm for 14, 28 or 90 days. General signs of toxicity were observed in Diuron-treated groups (1250 and 2500 ppm), including reduced food intake and body weight gain, as well as higher relative weights for spleen, kidneys and liver (28 and 90-day toxicity studies) and elevated serum levels of ALT, albumin, total protein, creatinine and urea (28-day toxicity study). Diuron exposure caused a severe depletion of splenic white pulp compartments and cellularity, followed by a decreased number of CD4(+) T lymphocytes, increased extramedullary hematopoiesis and deposition of hemosiderin in red pulp. Despite alteration in macrophage spreading, the macrophagic activity was not significantly affected by the herbicide. Under these experimental conditions, the results suggest that Diuron exerts systemic and target-organ toxicity, mainly at higher concentration.
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Affiliation(s)
- Alexandre Domingues
- Department of Pathology, Botucatu Medical School, São Paulo State University - UNESP, Botucatu 18618-970, São Paulo, Brazil.
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Grassi TF, Rodrigues MAM, de Camargo JLV, Barbisan LF. Evaluation of carcinogenic potential of diuron in a rat mammary two-stage carcinogenesis model. Toxicol Pathol 2011; 39:486-95. [PMID: 21398560 DOI: 10.1177/0192623310396904] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
This study aimed to evaluate the carcinogenic potential of the herbicide Diuron in a two-stage rat medium-term mammary carcinogenesis model initiated by 7,12-dimethylbenz(a)anthracene (DMBA). Female seven-week-old Sprague-Dawley (SD) rats were allocated to six groups: groups G1 to G4 received intragastrically (i.g.) a single 50 mg/kg dose of DMBA; groups G5 and G6 received single administration of canola oil (vehicle of DMBA). Groups G1 and G5 received a basal diet, and groups G2, G3, G4, and G6 were fed the basal diet with the addition of Diuron at 250, 1250, 2500, and 2500 ppm, respectively. After twenty-five weeks, the animals were euthanized and mammary tumors were histologically confirmed and quantified. Tumor samples were also processed for immunohistochemical evaluation of the expressions of proliferating cell nuclear antigen (PCNA), cleaved caspase-3, estrogen receptor-α (ER-α), p63, bcl-2, and bak. Diuron treatment did not increase the incidence or multiplicity of mammary tumors (groups G2 to G4 versus Group G1). Also, exposure to Diuron did not alter tumor growth (cell proliferation and apoptosis indexes) or immunoreactivity to ER-α, p63 (myoephitelial marker), or bcl-2 and bak (apoptosis regulatory proteins). These findings indicate that Diuron does not have a promoting potential on mammary carcinogenesis in female SD rats initiated with DMBA.
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Affiliation(s)
- Tony Fernando Grassi
- Medical School, UNESP-São Paulo State University, Department of Pathology, Botucatu-SP, Brazil
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Ferrucio B, Franchi CADS, Boldrin NF, Oliveira MLCSD, Camargo JLVD. Evaluation of Diuron (3-[3,4-dichlorophenyl]-1,1-dimethyl urea) in a Two-stage Mouse Skin Carcinogenesis Assay. Toxicol Pathol 2010; 38:756-64. [DOI: 10.1177/0192623310375452] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Diuron (3-[3,4-dichlorophenyl]-1,1-dimethyl urea) is an herbicide with carcinogenic activity in rats and mice, which have developed respectively urothelial and mammary gland tumors in long-term studies. Accordingly, diuron has been categorized as a “likely human carcinogen” by the U.S. Environmental Protection Agency. Although the carcinogenesis-initiating activity of diuron has been reported in an early initiation-promotion mouse skin study, its genotoxic potential has been disputed. It is necessary to clarify the mode of action through which it has caused rodent neoplasia and verify its relevance to humans. Herein, two experiments were developed to verify the initiating and promoting potentials of diuron in a twenty-three- and a twenty-one-week–long mouse skin carcinogenesis protocol. In one, dimethylsulfoxide (DMSO) was the solvent for the herbicide; in the other, acetone was the alternative solvent in order to verify whether DMSO had inhibitory influence on a potential cutaneous carcinogenic activity. The adopted schedule for the tumor-promoting agent 12-O-tetradecanoylphorbol 13-acetate (TPA) resulted in skin ulcers, which demonstrates the need for careful selection of TPA dose levels and frequency of application in this model. In both studies, diuron did not exert any influence on the skin carcinogenesis process, in contrast with results already reported in the literature.
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Affiliation(s)
- Bianca Ferrucio
- Center for the Evaluation of the Environmental Impact on Human Health (TOXICAM), Department of Pathology, Botucatu Medical School, UNESP - São Paulo State University, Botucatu, São Paulo, Brazil
| | - Carla Adriene da Silva Franchi
- Center for the Evaluation of the Environmental Impact on Human Health (TOXICAM), Department of Pathology, Botucatu Medical School, UNESP - São Paulo State University, Botucatu, São Paulo, Brazil
| | - Natália Ferreira Boldrin
- Center for the Evaluation of the Environmental Impact on Human Health (TOXICAM), Department of Pathology, Botucatu Medical School, UNESP - São Paulo State University, Botucatu, São Paulo, Brazil
| | - Maria Luiza Cotrim Sartor de Oliveira
- Center for the Evaluation of the Environmental Impact on Human Health (TOXICAM), Department of Pathology, Botucatu Medical School, UNESP - São Paulo State University, Botucatu, São Paulo, Brazil
| | - João Lauro Viana de Camargo
- Center for the Evaluation of the Environmental Impact on Human Health (TOXICAM), Department of Pathology, Botucatu Medical School, UNESP - São Paulo State University, Botucatu, São Paulo, Brazil
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de Moura NA, Grassi TF, Rodrigues MAM, Barbisan LF. Potential effects of the herbicide Diuron on mammary and urinary bladder two-stage carcinogenesis in a female Swiss mouse model. Arch Toxicol 2009; 84:165-73. [DOI: 10.1007/s00204-009-0477-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 10/08/2009] [Indexed: 11/29/2022]
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da Rocha MS, Nascimento MG, Cardoso APF, de Lima PLA, Zelandi EA, de Camargo JLV, de Oliveira MLCS. Cytotoxicity and Regenerative Proliferation as the Mode of Action for Diuron-Induced Urothelial Carcinogenesis in the Rat. Toxicol Sci 2009; 113:37-44. [DOI: 10.1093/toxsci/kfp241] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Cardone A, Comitato R, Angelini F. Spermatogenesis, epididymis morphology and plasma sex steroid secretion in the male lizard Podarcis sicula exposed to diuron. ENVIRONMENTAL RESEARCH 2008; 108:214-223. [PMID: 18760409 DOI: 10.1016/j.envres.2008.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 07/14/2008] [Accepted: 07/22/2008] [Indexed: 05/26/2023]
Abstract
The present study investigates the effects of diuron, a substituted urea-based herbicide, in the male lizard Podarcis sicula utilizing quantitative and qualitative morphological features of the reproductive system and endocrinological analysis. Besides the control group, lizards were divided into three groups ([a-c]) (n=6/group) and placed for 3 weeks in terraria on polluted soil substrate sprayed with 3.75 L/ha of herbicide Toterbane 50F (50% diuron). Each terrarium was supplemented either with drinking water contaminated by herbicide (i.e. 1.08 microg/mL of diuron; group [a]), or with food contaminated by herbicide (i.e. 5.4 mg of diuron; group [b]), or with drinking water and food contaminated as described above (group [c]). None of the animals exposed to the contaminant showed any signs of general toxicity or death during the course of the experiments. Severe testicular effects are evidenced in all herbicide-treated groups, although, such effects are of a greater magnitude in lizards exposed to contaminated water (groups [a] and [c]). The main degenerative changes observed include: (1) a significant decrease in the mean gonadosomatic index of 55% in group [a] (P<0.001), 21% in group [b] (P<0.01) and 34% in group [c] (P<0.001) compared with control group; (2) a significant shrinking (P<0.001) of seminiferous tubule diameter (more than 60% of the control) in groups [a] and [c], and about 18% in group [b] (P<0.01); (3) a significant decrease in the crude numbers of spermatogonia of 92% in group [a] (P<0.001), 27% in group [b] (P<0.01) and 62% in group [c] (P<0.001) compared with control group. A complete loss of meiotic and mature germ cells in groups [a] and [c], and a reduction of primary spermatocytes, secondary spermatocytes and spermatids (more than 27% of the control) and a decrease of spermatozoa (more than 90% of the control) in group [b]; and (4) an hypertrophy of interstitial connective tissue which contains numerous lymphocytes, neutrophils and monocytes. The decrease and/or loss of germ cells seems to be related to an induction of inflammation (necrosis) rather than to apoptotic processes. Indeed, this hypothesis is supported by a TUNEL-assay, which failed to reveal any apoptotic cells either in the seminiferous epithelium or in the interstitial space in the testis of all exposed groups. Also the epididymis appears affected by diuron exposure. In particular, in experimental groups [a] and [c] it is regressed with abundant connective tissue and low epithelial cells without secretory granules, whereas in group [b] it appears partially regressed, with some secretory granules still present. At the same time, an impairment of the plasma sex-hormone levels is observed in treated lizards, as evidenced by RIA analysis. Testosterone values significantly decreased by 43% in group [a] (P<0.001), 34% in group [b] (P<0.01) and 52% in group [c] compared with control group. Instead, 17beta-estradiol plasma content is undetectable in all diuron-exposed lizards. Taken together, the results presented here indicate that diuron exposure resulted in direct male reproductive toxicity and reveal that this lizard is suitable as a laboratory reptile species for toxicological investigations.
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Affiliation(s)
- Anna Cardone
- Department of Biological Science, Section of Evolutionary and Comparative Biology, University of Naples Federico II, Via Mezzocannone, 8. 80134 Naples, Italy.
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Fernandes GSA, Arena AC, Fernandez CDB, Mercadante A, Barbisan LF, Kempinas WG. Reproductive effects in male rats exposed to diuron. Reprod Toxicol 2007; 23:106-12. [PMID: 17070669 DOI: 10.1016/j.reprotox.2006.09.002] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 08/22/2006] [Accepted: 09/06/2006] [Indexed: 11/28/2022]
Abstract
Diuron is a ureic herbicide considered to have very low toxicity. The present study evaluated several aspects of reproductive toxicity of diuron in adult male rats. Diuron was diluted in corn oil and administered by oral gavage to groups of 18-20 rats at doses of 0, 125 or 250 mg/kg per day for 30 days; the control group received only the corn oil vehicle. At the end of the treatment period, approximately half the animals from each group were assigned to one of two terminal assessment lines: (1) reproductive organ, liver and kidney weights; measurement of diuron concentrations in liver and kidney; plasma testosterone determinations; evaluation of daily sperm production per testis; sperm number and sperm transit time in the epididymis; or (2) sexual behavior assessment during cohabitation with a receptive female; fertility and pregnancy outcome after natural mating; testicular, epididymal, kidney and liver histopathology; sperm morphology. After 30 days of oral diuron treatment, there were no treatment-related changes in body weights, but dose-related diuron residues were detected in the liver of all treated rats and absolute and relative liver weights were increased in both groups. There were no statistically significant differences between the treated and control groups obtained in plasma testosterone concentrations, or in parameters of daily sperm production, sperm reserves in the epididymis, sperm morphology or measured components of male sexual behavior. On the other hand, the number of fetuses in the litters from diuron-treated rats was slightly smaller than litters from control rats. Therefore, although the results did not indicate that diuron exposure resulted in direct male reproductive toxicity in the rat, they suggest that additional studies should be undertaken to investigate the possible effects on fertility and reproductive performance.
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Affiliation(s)
- Glaura S A Fernandes
- Departamento de Biologia Celular, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
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