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Tug T, Duda JC, Menssen M, Bruce SW, Bringezu F, Dammann M, Frötschl R, Harm V, Ickstadt K, Igl BW, Jarzombek M, Kellner R, Lott J, Pfuhler S, Plappert-Helbig U, Rahnenführer J, Schulz M, Vaas L, Vasquez M, Ziegler V, Ziemann C. In vivo alkaline comet assay: Statistical considerations on historical negative and positive control data. Regul Toxicol Pharmacol 2024; 148:105583. [PMID: 38401761 DOI: 10.1016/j.yrtph.2024.105583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/26/2024] [Accepted: 02/18/2024] [Indexed: 02/26/2024]
Abstract
The alkaline comet assay is frequently used as in vivo follow-up test within different regulatory environments to characterize the DNA-damaging potential of different test items. The corresponding OECD Test guideline 489 highlights the importance of statistical analyses and historical control data (HCD) but does not provide detailed procedures. Therefore, the working group "Statistics" of the German-speaking Society for Environmental Mutation Research (GUM) collected HCD from five laboratories and >200 comet assay studies and performed several statistical analyses. Key results included that (I) observed large inter-laboratory effects argue against the use of absolute quality thresholds, (II) > 50% zero values on a slide are considered problematic, due to their influence on slide or animal summary statistics, (III) the type of summarizing measure for single-cell data (e.g., median, arithmetic and geometric mean) may lead to extreme differences in resulting animal tail intensities and study outcome in the HCD. These summarizing values increase the reliability of analysis results by better meeting statistical model assumptions, but at the cost of information loss. Furthermore, the relation between negative and positive control groups in the data set was always satisfactorily (or sufficiently) based on ratio, difference and quantile analyses.
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Affiliation(s)
- Timur Tug
- Department of Statistics, TU Dortmund University, Dortmund, Germany.
| | - Julia C Duda
- Department of Statistics, TU Dortmund University, Dortmund, Germany
| | - Max Menssen
- Institute of Cell Biology and Biophysics, Department of Biostatistics, Leibniz University Hannover, Germany
| | | | - Frank Bringezu
- Merck Healthcare KGaA, Chemical and Preclinical Safety, Darmstadt, Germany
| | | | - Roland Frötschl
- Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
| | | | - Katja Ickstadt
- Department of Statistics, TU Dortmund University, Dortmund, Germany
| | - Bernd-Wolfgang Igl
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | | | - Rupert Kellner
- Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Hannover, Germany
| | - Jasmin Lott
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | | | | | | | | | | | | | | | - Christina Ziemann
- Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Hannover, Germany
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Møller P, Azqueta A, Collia M, Bakuradze T, Richling E, Bankoglu EE, Stopper H, Bastos VC, Langie SAS, Jensen A, Ristori S, Scavone F, Giovannelli L, Wojewódzka M, Kruszewski M, Valdiglesias V, Laffon B, Costa C, Costa S, Teixeira JP, Marino M, Del Bo C, Riso P, Zheng C, Shaposhnikov S, Collins A. Inter-laboratory variation in measurement of DNA damage by the alkaline comet assay in the hCOMET ring trial. Mutagenesis 2023; 38:283-294. [PMID: 37228081 DOI: 10.1093/mutage/gead014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/23/2023] [Indexed: 05/27/2023] Open
Abstract
The comet assay is a simple and versatile method for measurement of DNA damage in eukaryotic cells. More specifically, the assay detects DNA migration from agarose gel-embedded nucleoids, which depends on assay conditions and the level of DNA damage. Certain steps in the comet assay procedure have substantial impact on the magnitude of DNA migration (e.g. electric potential and time of electrophoresis). Inter-laboratory variation in DNA migration levels occurs because there is no agreement on optimal assay conditions or suitable assay controls. The purpose of the hCOMET ring trial was to test potassium bromate (KBrO3) as a positive control for the formamidopyrimidine DNA glycosylase (Fpg)-modified comet assay. To this end, participating laboratories used semi-standardized protocols for cell culture (i.e. cell culture, KBrO3 exposure, and cryopreservation of cells) and comet assay procedures, whereas the data acquisition was not standardized (i.e. staining of comets and image analysis). Segregation of the total variation into partial standard deviation (SD) in % Tail DNA units indicates the importance of cell culture procedures (SD = 10.9), comet assay procedures (SD = 12.3), staining (SD = 7.9) and image analysis (SD = 0.5) on the overall inter-laboratory variation of DNA migration (SD = 18.2). Future studies should assess sources of variation in each of these steps. On the positive side, the hCOMET ring trial demonstrates that KBrO3 is a robust positive control for the Fpg-modified comet assay. In conclusion, the hCOMET ring trial has demonstrated a high reproducibility of detecting genotoxic effects by the comet assay, but inter-laboratory variation of DNA migration levels is a concern.
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Affiliation(s)
- Peter Møller
- Department of Public Health, Section of Environmental Health, University of Copenhagen, Øster Farimagsgade 5A, DK-1014 Copenhagen K, Denmark
| | - Amaya Azqueta
- Department of Pharmacology and Toxicology, School of Pharmacy and Nutrition. University of Navarra, C/Irunlarrea 1, 31009 Pamplona, Spain
| | - Miguel Collia
- Department of Pharmacology and Toxicology, School of Pharmacy and Nutrition. University of Navarra, C/Irunlarrea 1, 31009 Pamplona, Spain
| | - Tamara Bakuradze
- Food Chemistry and Toxicology, Department of Chemistry, RPTU Kaiserslautern-Landau, Erwin-Schroedinger-Str. 52, D-67663 Kaiserslautern, Germany
| | - Elke Richling
- Food Chemistry and Toxicology, Department of Chemistry, RPTU Kaiserslautern-Landau, Erwin-Schroedinger-Str. 52, D-67663 Kaiserslautern, Germany
| | - Ezgi Eyluel Bankoglu
- Institute of Pharmacology and Toxicology, University of Wuerzburg, Versbacher Str. 9, 97078 Wuerzburg, Germany
| | - Helga Stopper
- Institute of Pharmacology and Toxicology, University of Wuerzburg, Versbacher Str. 9, 97078 Wuerzburg, Germany
| | - Victoria Claudino Bastos
- Department of Pharmacology & Toxicology, School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Sabine A S Langie
- Department of Pharmacology & Toxicology, School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Annie Jensen
- Department of Public Health, Section of Environmental Health, University of Copenhagen, Øster Farimagsgade 5A, DK-1014 Copenhagen K, Denmark
| | - Sara Ristori
- Department of Neuroscience, Psychology, Pharmacology and Child Health (NEUROFARBA), Section Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Francesca Scavone
- Department of Neuroscience, Psychology, Pharmacology and Child Health (NEUROFARBA), Section Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Lisa Giovannelli
- Department of Neuroscience, Psychology, Pharmacology and Child Health (NEUROFARBA), Section Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Maria Wojewódzka
- Centre for Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Dorodna 16, 01-310 Warsaw, Poland
| | - Marcin Kruszewski
- Centre for Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Dorodna 16, 01-310 Warsaw, Poland
- Department of Molecular Biology and Translational Research, Institute of Rural Health, Jaczewskiego 2, 20-090 Lublin, Poland
| | - Vanessa Valdiglesias
- Universidade da Coruña, Grupo NanoToxGen, Centro Interdisciplinar de Química e Bioloxía - CICA, Departamento de Biología, A Coruña, Spain
- Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain
| | - Blanca Laffon
- Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain
- Universidade da Coruña, Grupo DICOMOSA, Centro Interdisciplinar de Química e Bioloxía - CICA, Departamento de Psicología, A Coruña, Spain
| | - Carla Costa
- Environmental Health Department, National Institute of Health, Porto, Portugal
- EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
| | - Solange Costa
- Environmental Health Department, National Institute of Health, Porto, Portugal
- EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
| | - João Paulo Teixeira
- Environmental Health Department, National Institute of Health, Porto, Portugal
- EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
| | - Mirko Marino
- Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, 20133 Milan, Italy
| | - Cristian Del Bo
- Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, 20133 Milan, Italy
| | - Patrizia Riso
- Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, 20133 Milan, Italy
| | - Congying Zheng
- Department of Pharmacology & Toxicology, School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
- Department of Nutrition, University of Oslo, Oslo, Norway
| | | | - Andrew Collins
- Department of Nutrition, University of Oslo, Oslo, Norway
- NorGenotech AS, Oslo, Norway
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Plappert-Helbig U, Libertini S, Frieauff W, Theil D, Martus HJ. Gamma-H2AX immunofluorescence for the detection of tissue-specific genotoxicity in vivo. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:4-16. [PMID: 30307065 DOI: 10.1002/em.22238] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 06/08/2023]
Abstract
The phosphorylation of histone H2AX in Serine 139 (gamma-H2AX) marks regions of DNA double strand breaks and contributes to the recruitment of DNA repair factors to the site of DNA damage. Gamma-H2AX is used widely as DNA damage marker in vitro, but its use for genotoxicity assessment in vivo has not been extensively investigated. Here, we developed an image analysis system for the precise quantification of the gamma-H2AX signal, which we used to monitor DNA damage in animals treated with known genotoxicants (EMS, ENU and doxorubicin). To compare this new assay to a validated standard procedure for DNA damage quantification, tissues from the same animals were also analyzed in the comet assay. An increase in the levels of gamma-H2AX was observed in most of the tissues from animals treated with doxorubicin and ENU. Interestingly, the lesions induced by doxorubicin were not easily detected by the standard comet assay, while they were clearly identified by gamma-H2AX staining. Conversely, EMS appeared strongly positive in the comet assay but only mildly in the gamma-H2AX immunofluorescence. These observations suggest that the two methods could complement each other for DNA damage analysis, where gamma-H2AX staining allows the detection of tissue-specific effects in situ. Moreover, since gamma-H2AX staining can be performed on formalin-fixed and paraffin-embedded tissue sections generated during repeated-dose toxicity studies, it does not require any further treatments or extra procedures during dissection, thus optimizing the use of resources and animals. Environ. Mol. Mutagen. 60:4-16, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Silvana Libertini
- Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Wilfried Frieauff
- Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Diethilde Theil
- Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Hans-Jörg Martus
- Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
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Shruthi S, Bhasker Shenoy K. Genoprotective effects of gallic acid against cisplatin induced genotoxicity in bone marrow cells of mice. Toxicol Res (Camb) 2018; 7:951-958. [PMID: 30310672 PMCID: PMC6116806 DOI: 10.1039/c8tx00058a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/22/2018] [Indexed: 01/04/2023] Open
Abstract
Chemotherapeutic drugs are used for the treatment of cancer. However, the use of these drugs is limited due to their side effects on normal cells. One of the measures to detect chemoprotection of plant extracts is to evaluate their anticlastogenic effects. In this study, we report the anticlastogenic effect of gallic acid (GA) against cisplatin (Csp), a chemotherapeutic drug, in Swiss albino mice. Three different doses of GA (100, 200 and 400 mg per kg bw) were administered orally to the experimental animals in 0.2 mL quantity for 5 days at 24 hour intervals. Cisplatin, the positive control agent (10 mg per kg bw), was administered intraperitoneally (i.p.) in 0.1 mL quantity. Overall, the results showed that the pretreatment of GA caused a remarkable decrease in Csp induced micronucleus frequency and DNA damage in bone marrow cells of mice. The results suggest that GA showed potent antigenotoxic effects against Csp induced damage in mice bone marrow cells.
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Affiliation(s)
- S Shruthi
- Department of Applied Zoology , Alva's College , Vidyagiri , Moodbidri , D.K.-574 227 , Karnataka , India .
| | - K Bhasker Shenoy
- Department of Applied Zoology Mangalore University , Mangalagangothri , D.K.-574 199 , Karnataka , India .
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