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No evidence for genotoxicity in mice due to exposure to intermediate-frequency magnetic fields used for wireless power-transfer systems. Mutat Res 2021; 863-864:503310. [PMID: 33678242 DOI: 10.1016/j.mrgentox.2021.503310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 01/09/2021] [Accepted: 01/11/2021] [Indexed: 11/23/2022]
Abstract
Time varying magnetic fields (MFs) are used for the wireless power-transfer (WPT) technology. Especially, 85 kHz band MFs, which are included in the intermediate frequency (IF) band (300 Hz - 10 MHz), are commonly used WPT system for charging electric vehicles. Those applications of WPT technology have elicited public concern about health effects of IF-MF. However, existing data from health risk assessments are insufficient and additional data are needed. We assessed the genotoxic effects of IF-MF exposure on erythroid differentiation in mice. A high-intensity IF-MF mouse exposure system was constructed to induce an average whole-body electric field of 54.1 V/m. Blood samples were obtained from male mice before and after a 2-week IF-MF exposure (1 h/day, total: 10 h); X-irradiated mice were used as positive controls. We analyzed the blood samples with the micronucleus (MN) test and the Pig-a mutation assay. No significant differences were seen between IF-MF-exposed and sham-exposed mice in the frequencies of either MN or Pig-a mutations in mature erythrocytes and reticulocytes. IF-MF exposure did not induce genotoxicity in vivo under the study conditions (2.36× the basic restriction for occupational exposure, 22.9 V/m, in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines). The absence of significant biological effects due to IF-MF exposure supports the practical application of this technology.
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2
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Albertini RJ, Kaden DA. Mutagenicity monitoring in humans: Global versus specific origin of mutations. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 786:108341. [PMID: 33339577 DOI: 10.1016/j.mrrev.2020.108341] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 10/08/2020] [Accepted: 10/14/2020] [Indexed: 01/19/2023]
Abstract
An underappreciated aspect of human mutagenicity biomonitoring is tissue specificity reflected in different assays, especially those that measure events that can only occur in developing bone marrow (BM) cells. Reviewed here are 9 currently-employed human mutagenicity biomonitoring assays. Several assays measure chromosome-level events in circulating T-lymphocytes (T-cells), i.e., traditional analyses of aberrations, translocation studies involving chromosome painting and fluorescence in situ hybridization (FISH) and determinations of micronuclei (MN). Other T-cell assays measure gene mutations. i.e., hypoxanthine-guanine phosphoriboslytransferase (HPRT) and phosphoribosylinositol glycan class A (PIGA). In addition to the T-cell assays, also reviewed are those assays that measure events in peripheral blood cells that necessarily arose in BM cells, i.e., MN in reticulocytes; glycophorin A (GPA) gene mutations in red blood cells (RBCs), and PIGA gene mutations in RBC or granulocytes. This review considers only cell culture- or cytometry-based assays to describe endpoints measured, methods, optimal sampling times, and sample summaries of typical quantitative and qualitative results. However, to achieve its intended focus on the target cells where events occur, kinetics of the cells of peripheral blood that derive at some point from precursor cells are reviewed to identify body sites and tissues where the genotoxic events originate. Kinetics indicate that in normal adults, measured events in T-cells afford global assessments of in vivo mutagenicity but are not specific for BM effects. Therefore, an agent's capacity for inducing mutations in BM cells cannot be reliably inferred from T-cell assays as the magnitude of effect in BM, if any, is unknown. By contrast, chromosome or gene level mutations measured in RBCs/reticulocytes or granulocytes must originate in BM cells, i.e. in RBC or granulocyte precursors, thereby making them specific indicators for effects in BM. Assays of mutations arising directly in BM cells may quantitatively reflect the mutagenicity of potential leukemogenic agents.
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Affiliation(s)
- Richard J Albertini
- University of Vermont, 111 Colchester Avenue, Burlington, VT 05401, United States
| | - Debra A Kaden
- Ramboll US Consulting, Inc., 101 Federal Street, Suite 1900, Boston, MA 02110, United States.
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3
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Chen Y, Huo J, Liu Y, Zeng Z, Zhu X, Chen X, Wu R, Zhang L, Chen J. Development of a novel flow cytometry-based approach for reticulocytes micronucleus test in rat peripheral blood. J Appl Toxicol 2020; 41:595-606. [PMID: 33067908 DOI: 10.1002/jat.4068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 08/25/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022]
Abstract
The micronucleus test (MNT) is the most widely applied short-term assay to detect clastogens or spindle disruptors. The use of flow cytometry (FCM) has been reported for micronucleated erythrocytes scoring in peripheral blood. The aim of this study was to develop a novel and practical protocol for MNT in rat peripheral blood by FCM, with the method validation. CD71-fluorescein isothiocyanate and DRAQ5 were adopted for the fluorescent staining of proteins and DNA, respectively, to detect micronuclei. To validate the method, groups of male Sprague-Dawley rats (five per group) received two oral gavage doses at 0 and 24 h of six chemicals (four positive mutagens: ethyl methanesulphonate [EMS], cyclophosphamide [CP], colchicine [COL], and ethyl nitrosourea [ENU]; two nongenotoxic chemicals: sodium saccharin and eugenol). Blood samples were collected from the tail vein before and on the five continuous days after treatments; all of which were analyzed for micronuclei presence by both the manual (Giemsa staining) and FCM methods. The FCM-based method consistently demonstrated highly sensitive responses for micronucleus detection at all concentrations and all time points for EMS, CP, COL, and ENU. Sodium saccharin and eugenol could be identified as negative in this protocol. Results obtained with the FCM-based method correlated well with the micronucleus frequencies (r = 0.659-0.952), and the proportion of immature erythrocytes (r = 0.915-0.981) tested by Giemsa staining. The method reported here, with easy operation, low background, and requirement for a regular FCM, could be an efficient system for micronucleus scoring.
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Affiliation(s)
- Yiyi Chen
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.,Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Sichuan University, Chengdu, China
| | - Jiao Huo
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.,Department of Nutrition and Food Safety, Chongqing Center for Disease Control and Prevention, Chongqing, China
| | - Yunjie Liu
- Graduate Department, West China School of Public Health, Sichuan University, Chengdu, China
| | - Zhu Zeng
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.,Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Sichuan University, Chengdu, China
| | - Xuejiao Zhu
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.,Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Sichuan University, Chengdu, China
| | - Xuxi Chen
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.,Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Sichuan University, Chengdu, China
| | - Rui Wu
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.,Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Sichuan University, Chengdu, China
| | - Lishi Zhang
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.,Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Sichuan University, Chengdu, China
| | - Jinyao Chen
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.,Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Sichuan University, Chengdu, China
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Pitt J, Chan M, Gibson C, Hasselwander O, Lim A, Mukerji P, Mukherjea R, Myhre A, Sarela P, Tenning P, Himmelstein MW, Roper JM. Safety assessment of the biotechnologically produced human-identical milk oligosaccharide 3-Fucosyllactose (3-FL). Food Chem Toxicol 2019; 134:110818. [PMID: 31533061 DOI: 10.1016/j.fct.2019.110818] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 10/26/2022]
Abstract
3-Fucosyllactose (3-FL), a highly abundant complex carbohydrate in human breast milk, functions as a prebiotic promoting early microbial colonization of the gut, increasing pathogen resistance and modulating immune responses. To investigate potential health benefits, 3-FL was produced by fermentation using a genetically modified E. coli K12 strain. The safety assessment of 3-FL included acute oral toxicity, in vitro and in vivo assessment of genetic toxicity, and a subchronic rodent feeding study. 3-FL was not acutely toxic at 5000 mg/kg bw, and there was no evidence of genetic toxicity in the bacterial reverse mutation test and chromosomal aberration assay. There was a repeatable statistically-significant trend in the 4-h S9-activated test conditions in the in vitro micronucleus assay; the confirmatory in vivo mouse micronucleus study was negative at all doses. Dietary subchronic exposure of rats to 3-FL (5% and 10%) did not produce any statistical or biologically-relevant differences in growth, food intake or efficiency, clinical observations, or clinical or anatomic pathology changes at average daily intakes of 5.98 and 7.27 g/kg bw/day for males and females, respectively. The weight of evidence from these studies support the safe use of 3-FL produced using biotechnology as a nutritional ingredient in foods.
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Affiliation(s)
- J Pitt
- DuPont Nutrition and Biosciences, 1801 Larkin Center Drive, Midland, MI, 48674, USA.
| | - M Chan
- Corteva™, Agriscience™, P.O. Box 30, Newark, DE, 19714, USA
| | - C Gibson
- Total Pathology Solutions, LLC, Kennett Square, PA, 19348, USA
| | - O Hasselwander
- DuPont Nutrition and Biosciences, 43 London Road, Reigate, Surrey, RH2 9PW, UK
| | - A Lim
- DuPont Nutrition and Biosciences, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - P Mukerji
- Corteva™, Agriscience™, P.O. Box 30, Newark, DE, 19714, USA
| | - R Mukherjea
- DuPont Nutrition and Biosciences, 4300 Duncan Ave, St. Louis MO, 63110, USA
| | - A Myhre
- Corteva™, Agriscience™, P.O. Box 30, Newark, DE, 19714, USA
| | - P Sarela
- DuPont Nutrition and Biosciences, Sokeritehtaanti 20, FI- 02460, Kantvik, FI, USA
| | - P Tenning
- DuPont Nutrition and Biosciences, Langebrogade 1, DK-1411, Copenhagen K, DE, USA
| | | | - J M Roper
- Corteva™, Agriscience™, P.O. Box 30, Newark, DE, 19714, USA
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Huang YC, Hsu CC, Wang JS. High-Intensity Interval Training Improves Erythrocyte Osmotic Deformability. Med Sci Sports Exerc 2019; 51:1404-1412. [PMID: 30768550 DOI: 10.1249/mss.0000000000001923] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Physical exercise or hypoxic exposure influences erythrocyte susceptibility to osmotic stress, and the aquaporin 1 (AQP1) facilitates the transport of water in erythrocytes. This study investigated whether high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) affect erythrocyte osmotic deformability by modulating AQP1 function under hypoxic stress. METHODS Forty-five healthy sedentary males were randomized to engage in either HIIT (3-min intervals at 40% and 80% V˙O2 reserve, n = 15) or MICT (sustained 60% V˙O2 reserve, n = 15) on a bicycle ergometer for 30 min·d, 5 d·wk for 6 wk, or to a control group that did not perform any exercise (n = 15). All subjects were analyzed with osmotic gradient ektacytometry for assessing erythrocyte membrane stability and osmotic deformability after hypoxic exercise (HE) (100 W under 12%O2 for 30 min). RESULTS Before the intervention, HE increased the shear stress at 50% of maximal elongation (SS1/2) and the ratio of SS1/2 to maximal elongation index (SS1/2/EImax) on erythrocytes pretreated with 50 Pa of shear stress for 30 min and diminished HgCl2-depressed osmolality at 50%EImax (Ohyper). However, both HIIT and MICT for 6 wk diminished the elevations of erythrocyte SS1/2 and SS1/2/EImax caused by HE. Moreover, HIIT also increased contents of erythrocyte AQP1 proteins while enhancing HgCl2-depressed Ohyper and area under elongation index-osmolarity curve after HE. Additionally, changes in erythrocyte AQP1 contents were associated with changes in HgCl2-depressed erythrocyte Ohyper and area under elongation index-osmolarity curve. CONCLUSIONS Acute HE reduces erythrocyte membrane stability, whereas either HIIT or MICT attenuates the depression of erythrocyte membrane stability by HE. Moreover, HIIT increases the AQP1 content and facilitates the HgCl2-mediated osmotic deformability of erythrocytes after HE.
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Affiliation(s)
- Yu-Chieh Huang
- Healthy Aging Research Center, Graduate Institute of Rehabilitation Science, Medical Collage, Chang Gung University, Tao-Yuan, TAIWAN
| | - Chih-Chin Hsu
- Heart Failure Center, Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Keelung, TAIWAN
| | - Jong-Shyan Wang
- Healthy Aging Research Center, Graduate Institute of Rehabilitation Science, Medical Collage, Chang Gung University, Tao-Yuan, TAIWAN.,Heart Failure Center, Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Keelung, TAIWAN.,Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Tao-Yuan, TAIWAN
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6
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Chen G, Wen H, Mao Z, Song J, Jiang H, Wang W, Yang Y, Miao Y, Wang C, Huang Z, Wang X. Assessment of the Pig-a, micronucleus, and comet assay endpoints in rats treated by acute or repeated dosing protocols with procarbazine hydrochloride and ethyl carbamate. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:56-71. [PMID: 30240497 DOI: 10.1002/em.22227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/12/2018] [Accepted: 06/24/2018] [Indexed: 06/08/2023]
Abstract
The utility and sensitivity of the newly developed flow cytometric Pig-a gene mutation assay have become a great concern recently. In this study, we have examined the feasibility of integrating the Pig-a assay as well as micronucleus and Comet endpoints into acute and subchronic general toxicology studies. Male Sprague-Dawley rats were treated for 3 or 28 consecutive days by oral gavage with procarbazine hydrochloride (PCZ) or ethyl carbamate (EC) up to the maximum tolerated dose. The induction of CD59-negative reticulocytes and erythrocytes, micronucleated reticulocytes in peripheral blood, micronucleated polychromatic erythrocytes in bone marrow, and Comet responses in peripheral blood, liver, kidney, and lung were evaluated at one, two, or more timepoints. Both PCZ and EC produced positive responses at most analyzed timepoints in all tissue types, both with the 3-day and 28-day treatment regimens. Furthermore, comparison of the magnitude of the genotoxicity responses indicated that the micronucleus and Comet endpoints generally produced greater responses with the higher dose, short-term treatments in the 3-day study, while the Pig-a assay responded better to the cumulative effects of the lower dose, but repeated subchronic dosing in the 28-day study. Collectively, these results indicate that integration of several in vivo genotoxicity endpoints into a single routine toxicology study is feasible and that the Pig-a assay may be particularly suitable for integration into subchronic dose studies based on its ability to accumulate the mutations that result from repeated treatments. This characteristic may be especially important for assaying lower doses of relatively weak genotoxicants. Environ. Mol. Mutagen. 60:56-71, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Gaofeng Chen
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
- Center of Safety Evaluation on New Drug, School of Pharmaceutical Science, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Hairuo Wen
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Zhihui Mao
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
- Center of Safety Evaluation on New Drug, School of Pharmaceutical Science, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Jie Song
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Hua Jiang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Weifan Wang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Ying Yang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Yufa Miao
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Chao Wang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Zhiying Huang
- Center of Safety Evaluation on New Drug, School of Pharmaceutical Science, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Xue Wang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
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An updated review of the genotoxicity of respirable crystalline silica. Part Fibre Toxicol 2018; 15:23. [PMID: 29783987 PMCID: PMC5963024 DOI: 10.1186/s12989-018-0259-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 05/09/2018] [Indexed: 12/22/2022] Open
Abstract
Human exposure to (certain forms of) crystalline silica (CS) potentially results in adverse effects on human health. Since 1997 IARC has classified CS as a Group 1 carcinogen [1], which was confirmed in a later review in 2012 [2]. The genotoxic potential and mode of genotoxic action of CS was not conclusive in either of the IARC reviews, although a proposal for mode of actions was made in an extensive review of the genotoxicity of CS by Borm, Tran and Donaldson in 2011 [3]. The present study identified 141 new papers from search strings related to genotoxicity of respirable CS (RCS) since 2011 and, of these, 17 relevant publications with genotoxicity data were included in this detailed review. Studies on in vitro genotoxic endpoints primarily included micronucleus (MN) frequency and % fragmented DNA as measured in the comet assay, and were mostly negative, apart from two studies using primary or cultured macrophages. In vivo studies confirmed the role of persistent inflammation due to quartz surface toxicity leading to anti-oxidant responses in mice and rats, but DNA damage was only seen in rats. The role of surface characteristics was strengthened by in vitro and in vivo studies using aluminium or hydrophobic treatment to quench the silanol groups on the CS surface. In conclusion, the different modes of action of RCS-induced genotoxicity have been evaluated in a series of independent, adequate studies since 2011. Earlier conclusions on the role of inflammation driven by quartz surface in genotoxic and carcinogenic effects after inhalation are confirmed and findings support a practical threshold. Whereas classic in vitro genotoxicity studies confirm an earlier no-observed effect level (NOEL) in cell cultures of 60-70 μg/cm2, transformation frequency in SHE cells suggests a lower threshold around 5 μg/cm2. Both levels are only achieved in vivo at doses (2–4 mg) beyond in vivo doses (> 200 μg) that cause persistent inflammation and tissue remodelling in the rat lung.
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Avlasevich SL, Khanal S, Singh P, Torous DK, Bemis JC, Dertinger SD. Flow cytometric method for scoring rat liver micronuclei with simultaneous assessments of hepatocyte proliferation. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:176-187. [PMID: 29356121 PMCID: PMC5854533 DOI: 10.1002/em.22168] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/20/2017] [Indexed: 05/28/2023]
Abstract
The current report describes a newly devised method for automatically scoring the incidence of rat hepatocyte micronuclei (MNHEP) via flow cytometry, with concurrent assessments of hepatocyte proliferation-frequency of Ki-67-positive nuclei, and the proportion of polyploid nuclei. Proof-of-concept data are provided from experiments performed with 6-week old male Crl:CD(SD) rats exposed to diethylnitrosamine (DEN) or quinoline (QUIN) for 3 or 14 consecutive days. Non-perfused liver tissue was collected 4 days after cessation of treatment in the case of 3-day studies, or 1 day after last administration in the case of 14-day studies for processing and flow cytometric analysis. In addition to livers, blood samples were collected one day after final treatment for micronucleated reticulocyte (MN-RET) measurements. Dose-dependent increases in MNHEP, Ki-67-positive nuclei, and polyploidy were observed in 3- and 14-day DEN studies. Both treatment schedules resulted in elevated %MNHEP for QUIN-exposed rats, and while cell proliferation effects were subtle, appreciable increases to normalized liver weights were observed. Whereas DEN caused markedly higher %MNHEP when exposure was extended to two weeks, QUIN-induced MNHEP were slightly increased with protracted dosing. Parallel microscopy-based MNHEP frequencies were highly correlated with flow cytometry-based measurements (four study/aggregate R2 = 0.80). No increases in MN-RET were seen in any of the four studies. Collectively, these results suggest liver micronuclei are amenable to an automated scoring technique that provides objective analyses and higher information content relative to conventional microscopy. Additional work is needed to expand the number and types of chemicals tested, identify the most advantageous treatment schedules, and test the transferability of the method. Environ. Mol. Mutagen. 59:176-187, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
| | | | | | | | | | - Stephen D. Dertinger
- Corresponding Author: S.D.D., Litron Laboratories, 3500 Winton Place, Rochester, NY 14623; Tele: 585-442-0930; fax: 585-442-0934;
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Chou SL, Huang YC, Fu TC, Hsu CC, Wang JS. Cycling Exercise Training Alleviates Hypoxia-Impaired Erythrocyte Rheology. Med Sci Sports Exerc 2016; 48:57-65. [PMID: 26672920 DOI: 10.1249/mss.0000000000000730] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
PURPOSE Physical exercise or hypoxic exposure influences hemorheology and acid-base homeostasis. Band 3 protein in erythrocytes modulates cells' rheological properties and anion transport ability. This study investigated how cycling aerobic interval training (AIT) and moderate continuous training (MCT) affect the rheological function and band 3 activity of erythrocytes under hypoxic exercise (HE) stress. METHODS Forty-five healthy sedentary men were randomized to engage in either AIT (3-min intervals at 40% and 80% of VO2max, n = 15) or MCT (sustained 60% of VO2max, n = 15) on a bicycle ergometer for 30 min · d(-1) (5 d · wk(-1) for 5 wk) or to a control group that did not perform any exercise (n = 15). Erythrocyte rheological responses to HE (100 W under 12% O2 for 30 min) were determined before and after various regimens. RESULTS Acute HE increased the aggregation and osmotic fragility of erythrocytes, decreased the deformability of erythrocytes, and depressed erythrocyte band 3 activity, as indicated by lowered anion transport ability. Following 5 wk of intervention, the AIT group exhibited maximal work rate and VO2max higher than those in the MCT and control groups. Moreover, cycling AIT and MCT diminished the extent of erythrocytes' enhanced aggregation and osmotic fragility and reduced their deformability and band 3 activity caused by HE. Additionally, erythrocyte band 3 activity was directly related to erythrocyte deformability and inversely related to erythrocyte aggregation and osmotic fragility. CONCLUSIONS Cycling AIT is superior to cycling MCT in enhancing aerobic capacity. Moreover, either cycling AIT or MCT effectively alleviates HE-evoked impairments of erythrocyte rheological characteristics and band 3 function.
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Affiliation(s)
- Szu-Ling Chou
- 1Heart Failure Center, Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Keelung, TAIWAN; and 2Healthy Aging Research Center, Graduate Institute of Rehabilitation Science, Medical College, Chang Gung University, Tao-Yuan, TAIWAN
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10
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Li Y, Doak SH, Yan J, Chen DH, Zhou M, Mittelstaedt RA, Chen Y, Li C, Chen T. Factors affecting the in vitro micronucleus assay for evaluation of nanomaterials. Mutagenesis 2016; 32:151-159. [PMID: 27567283 DOI: 10.1093/mutage/gew040] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A number of in vitro methodologies have been used to assess the genotoxicity of different nanomaterials, including titanium dioxide nanoparticles (TiO2 NPs) and silver nanoparticles (AgNPs). The in vitro micronucleus assay is one of the most commonly used test methods for genotoxicity evaluation of nanomaterials. However, due to the novel features of nanomaterials, such as high adsorption capacity and fluorescence properties, there are unexpected interactions with experimental components and detection systems. In this study, we evaluate the interference by two nanoparticles, AgNPs and TiO2 NPs, with the in vitro micronucleus assay system and possible confounding factors affecting cytotoxicity and genotoxicity assessment of the nanomaterials including cell lines with different p53 status, nanoparticle coatings and fluorescence, cytochalasin B, fetal bovine serum in cell treatment medium and different measurement methodologies for detecting micronuclei. Our results showed that micronucleus induction by AgNPs was similar when evaluated using flow cytometry or microscope, whereas the induction by TiO2 NPs was different using the two methods due to TiO2's fluorescence interference with the cytometry equipment. Cells with the mutated p53 gene were more sensitive to micronucleus induction by AgNPs than the p53 wild-type cells. The presence of serum during treatment increased the toxicity of AgNPs. The coatings of nanoparticles played an important role in the genotoxicity of AgNPs. These collective data highlight the importance of considering the unique properties of nanoparticles in assessing their genotoxicity using the in vitro micronucleus assay.
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Affiliation(s)
- Yan Li
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA.,Covance Laboratories Inc. 671 S. Meridian Rd., Greenfield, IN 46140, USA
| | - Shareen H Doak
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea SA2 8PP, Wales, UK
| | - Jian Yan
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA
| | - David H Chen
- Columbia College, Columbia University in the City of New York, 2960 Broadway, New York, NY 10027, USA and
| | - Min Zhou
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, 1881 East Road, Houston, TX 77054, USA
| | - Roberta A Mittelstaedt
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA
| | - Ying Chen
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA
| | - Chun Li
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, 1881 East Road, Houston, TX 77054, USA
| | - Tao Chen
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA,
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11
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Inter-laboratory validation of the in-vivo flow cytometric micronucleus analysis method (MicroFlow®) in China. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 772:6-13. [PMID: 25308541 DOI: 10.1016/j.mrgentox.2014.04.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 03/19/2014] [Accepted: 04/30/2014] [Indexed: 12/23/2022]
Abstract
Although inter-laboratory validation efforts of the in-vivo micronucleus (MN) assay based on flow cytometry (FCM) have taken place in the EU and US, none have been organized in China. Therefore, an inter-laboratory study that included eight laboratories in China and one experienced reference laboratory in the US was coordinated to validate the in-vivo FCM MicroFlow(®) method to determine the frequency of micro-nucleated reticulocytes (MN-RETs) in rat blood. Assay reliability and reproducibility were evaluated with four known genotoxicants, and the results obtained with the FCM method were compared with the outcome of the traditional evaluation of bone-marrow micronuclei by use of microscopy. Each of the four chemicals was tested at three sites (two in China and the one US reference laboratory). After three consecutive daily exposures to a genotoxicant, blood and bone-marrow samples were obtained from rats 24h after the third dose. MN-RET frequencies were measured in 20,000 RET in blood by FCM, and micro-nucleated polychromatic erythrocyte (MN-PCE) frequencies were measured in 2,000 PCEs in bone marrow by microscopy. For both methods, each genotoxicant was shown to induce a statistically significant increase in the frequency of MN after treatment with at least one dose. Where more doses than one caused an increase, responses occurred in a dose-dependent manner. Spearman's correlation coefficient (rs) for FCM-based MN-RET vs microscopy-based MN-PCE measurements (eight experiments, 200 paired measurements) was 0.723, indicating a high degree of correspondence between methods and compartments. The rs value for replicate FCM MN-RET measurements performed at the eight collaborative laboratories was 0.940 (n=200), and between the eight FCM laboratories with the reference laboratory was 0.933 (n=200), suggesting that the automated method is very well transferable between laboratories. The FCM micronucleus analysis method is currently used in many countries worldwide, and these data support its use for evaluating the in-vivo genotoxic potential of test chemicals in China.
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Shibai-Ogata A, Tahara H, Yamamoto Y, Fujita M, Satoh H, Yuasa A, Hioki T, Kasahara T. An automated new technique for scoring the in vivo micronucleus assay with image analysis. Mutagenesis 2014; 29:63-71. [PMID: 24342936 DOI: 10.1093/mutage/get064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The mammalian erythrocyte micronucleus assay is frequently used to assess chemical-induced damage to the chromosomes or the mitotic apparatus of erythroblasts. Because quantitative analysis of micronuclei by microscopy is time consuming and laborious, several automatic scoring methodologies with image analysis have been reported. However, there have been cases in which it was difficult to examine the proportion of polychromatic erythrocytes (PCEs) among total erythrocytes as an index for bone marrow (BM) toxicity, and sample slide preparation has proven to be laborious with existing automatic methods. We developed an automatic scoring system with image analysis for the rodent erythrocyte micronucleus assay using 12-well plates employing high-content screening analyser. In our method, micronucleated PCEs (MNPCEs), PCEs and erythrocytes were identified from three kinds of images: bright field image, fluorescence image with Hoechst 33342, and fluorescence image with propidium iodide. The frequencies of MNPCEs and PCEs were subsequently calculated. A comparison of automatic and manual scoring was carried out using BM and peripheral blood (PB) obtained from mice treated with stepwise doses of mitomycin C. The scores obtained by automatic analysis corresponded to those obtained by manual scoring; the frequencies of MNPCEs in BM and PB obtained by automatic scoring were 132 and 113%, respectively, of those obtained by manual scoring, and the corresponding frequencies of PCEs were 95 and 120%, respectively. Furthermore, we performed five repeats of the examinations of mouse BM and PB treated with mitomycin C or vinblastine sulphate and showed that automatic scoring was equivalent to manual scoring in reproducibility. Meanwhile, the scoring data obtained by manual scoring tended to vary among observers. These results suggest that our automatic scoring system with image analysis is superior to manual microscopy scoring in terms of speed and objectivity, comparable in reproducibility and useful for the in vivo micronucleus assay.
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Affiliation(s)
- Aya Shibai-Ogata
- Safety Evaluation Center, Fujifilm Corporation, 210 Nakanuma, Minamiashigara-shi, Kanagawa 250-0193, Japan
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Comparison of three-colour flow cytometry and slide-based microscopy for the scoring of micronucleated reticulocytes in rat bone-marrow and peripheral blood. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 758:12-7. [DOI: 10.1016/j.mrgentox.2013.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/11/2013] [Accepted: 07/08/2013] [Indexed: 11/18/2022]
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Effect of aerobic interval training on erythrocyte rheological and hemodynamic functions in heart failure patients with anemia. Int J Cardiol 2013. [DOI: 10.1016/j.ijcard.2012.11.053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Elsayh KI, Sayed DM, Zahran AM, Saad K, Badr G. Effects of pneumonia and malnutrition on the frequency of micronuclei in peripheral blood of pediatric patients. Int J Clin Exp Med 2013; 6:942-50. [PMID: 24260601 PMCID: PMC3832332 DOI: pmid/24260601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 10/21/2013] [Indexed: 02/08/2023]
Abstract
UNLABELLED The aim of this study was to evaluate the effects of bacterial pneumonia and malnutrition on the frequency of micronuclei (MN) in peripheral blood of pediatric patients through flow cytometric analysis. The study was an analytical case-control study carried out on 35 malnourished children with bacterial pneumonia and 20 well-nourished children with bacterial pneumonia, in addition to 20 healthy children as controls. Complete physical examination including; anthropometric measurement, Chest roentgenograms were done for all cases. Assessment of MN was done by FACSCalibur flow cytometry. The frequency of micronucleated reticulocytes (MN-RETs) was higher both in the malnourished children with pneumonia and well-nourished children with pneumonia than the controls. Within the malnourished children with pneumonia, patients with kwashiorkor had more micronucleated mature erythrocytes (MN-RBCs) and MN-RETs than patients with marasmus. IN CONCLUSION Pneumonia is associated with an increased frequency of MN and this increment is more pronounced in children with severe malnutrition especially kwashiorkor group.
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Affiliation(s)
- Khalid I Elsayh
- Department of Pediatrics, Assiut UniversityAssiut 71516, Egypt
| | - Douaa M Sayed
- Department of Clinical Pathology, South Egypt Cancer Institute, Assiut UniversityAssiut 71516, Egypt
| | - Asmaa M Zahran
- Department of Clinical Pathology, South Egypt Cancer Institute, Assiut UniversityAssiut 71516, Egypt
| | - Khaled Saad
- Department of Pediatrics, Assiut UniversityAssiut 71516, Egypt
| | - Gamal Badr
- Princess Al-Johara Al-Ibrahim Center for Cancer Research, College of Medicine, King Saud UniversityRiyadh, Saudi Arabia
- Laboratory of Immunology & Molecular Biology, Department of Zoology, Faculty of Science, Assiut University71516, Assiut, Egypt
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Gaté L, Micillino JC, Sébillaud S, Langlais C, Cosnier F, Nunge H, Darne C, Guichard Y, Binet S. Genotoxicity of styrene-7,8-oxide and styrene in Fisher 344 rats: a 4-week inhalation study. Toxicol Lett 2012; 211:211-9. [PMID: 22507543 DOI: 10.1016/j.toxlet.2012.03.796] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 03/20/2012] [Accepted: 03/21/2012] [Indexed: 10/28/2022]
Abstract
The cytogenetic alterations in leukocytes and the increased risk for leukemia, lymphoma, or all lymphohematopoietic cancer observed in workers occupationally exposed to styrene have been associated with its hepatic metabolisation into styrene-7,8-oxide, an epoxide which can induce DNA damages. However, it has been observed that styrene-7,8-oxide was also found in the atmosphere of reinforced plastic industries where large amounts of styrene are used. Since the main route of exposure to these compounds is inhalation, in order to gain new insights regarding their systemic genotoxicity, Fisher 344 male rats were exposed in full-body inhalation chambers, 6 h/day, 5 days/week for 4 weeks to styrene-7,8-oxide (25, 50, and 75 ppm) or styrene (75, 300, and 1000 ppm). Then, the induction of micronuclei in circulating reticulocytes and DNA strand breaks in leukocytes using the comet assay was studied at the end of the 3rd and 20th days of exposure. Our results showed that neither styrene nor styrene-7,8-oxide induced a significant increase of the micronucleus frequency in reticulocytes or DNA strand breaks in white blood cells. However, in the presence of the formamidopyridine DNA glycosylase, an enzyme able to recognize and excise DNA at the level of some oxidized DNA bases, a significant increase of DNA damages was observed at the end of the 3rd day of treatment in leukocytes from rats exposed to styrene but not to styrene-7,8-oxide. This experimental design helped to gather new information regarding the systemic genotoxicity of these two chemicals and may be valuable for the risk assessment associated with an occupational exposure to these molecules.
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Affiliation(s)
- Laurent Gaté
- Institut National de Recherche et Sécurité, Rue du Morvan, CS 60027, 54519 Vandoeuvre les Nancy Cedex, France.
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Exertional periodic breathing potentiates erythrocyte rheological dysfunction by elevating pro-inflammatory status in patients with anemic heart failure. Int J Cardiol 2012; 167:1289-97. [PMID: 22521383 DOI: 10.1016/j.ijcard.2012.03.170] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 03/30/2012] [Indexed: 01/27/2023]
Abstract
BACKGROUND Exertional periodic breathing (EPB) or anemia is associated with an adverse prognosis in advanced heart failure (HF). The disturbed rheological properties of erythrocytes may contribute to circulatory disorders. This study investigated whether EPB with/without anemia influences rheological/hemodynamic functions in patients with HF. METHODS According to the WHO criteria for anemia, 168 HF patients were divided into six groups: non (N)-anemic with (n=27)/without (n=56) EPB, light (L)-anemic with (n=17)/without (n=21) EPB, and moderate/several (M/S)-anemic with (n=21)/without (n=26) EPB groups. These HF patients and 30 healthy counterparts performed an incremental exercise test using a bicycle ergometer. Rheological and hemodynamic characteristics were determined by slit-flow ektacytometer and bioreactance-based device/near infrared spectrometer, respectively. RESULTS In the HF patients with EPB, both L- and M/S-anemic groups exhibited 1) higher plasma myeloperoxidase/interleukin-6 concentrations, 2) more blood senescent/spherical erythrocyte counts, 3) larger aggregability and smaller deformability of erythrocytes under shear flows, 4) higher systemic vascular resistance, which was accompanied by smaller amounts of blood distributed to cerebral/muscular tissues during exercise, 5) less VO(2peak) and ventilatory efficiency, and 6) lower Short Form-36 physical/mental component scores and higher Minnesota Living with HF questionnaire score than N-anemic group. Additionally, plasma myeloperoxidase/interleukin-6 levels were directly related to erythrocyte aggregability and inversely related to erythrocyte deformability. However, there were no significant differences in pro-inflammatory factors, rheological/hemodynamic properties, and aerobic capacity between L- and N-anemic groups in the HF patients without EPB. CONCLUSION EPB potentiates anemia-related rheological/hemodynamic dysfunctions by elevating pro-inflammatory status, reducing physical fitness in patients with HF.
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Downs TR, Crosby ME, Hu T, Kumar S, Sullivan A, Sarlo K, Reeder B, Lynch M, Wagner M, Mills T, Pfuhler S. Silica nanoparticles administered at the maximum tolerated dose induce genotoxic effects through an inflammatory reaction while gold nanoparticles do not. Mutat Res 2012; 745:38-50. [PMID: 22504169 DOI: 10.1016/j.mrgentox.2012.03.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 03/28/2012] [Indexed: 11/27/2022]
Abstract
While the collection of genotoxicity data and insights into potential mechanisms of action for nano-sized particulate materials (NPs) are steadily increasing, there is great uncertainty whether current standard assays are suitable to appropriately characterize potential risks. We investigated the effects of NPs in an in vivo Comet/micronucleus (MN) combination assay and in an in vitro MN assay performed with human blood. We also incorporated additional endpoints into the in vivo study in an effort to delineate primary from secondary mechanisms. Amorphous silica NPs (15 and 55 nm) were chosen for their known reactivity, while gold nano/microparticles (2, 20, and 200 nm) were selected for their wide size range and lower reactivity. DNA damage in liver, lung and blood cells and micronuclei in circulating reticulocytes were measured after 3 consecutive intravenous injections to male Wistar rats at 48, 24 and 4h before sacrifice. Gold nano/microparticles were negative for MN induction in vitro and in vivo, and for the induction of DNA damage in all tissues. Silica particles, however, caused a small but reproducible increase in DNA damage and micronucleated reticulocytes when tested at their maximum tolerated dose (MTD). No genotoxic effects were observed at lower doses, and the in vitro MN assay was also negative. We hypothesize that silica NPs initiate secondary genotoxic effects through release of inflammatory cell-derived oxidants, similar to that described for crystalline silica (quartz). Such a mechanism is supported by the occurrence of increased neutrophilic infiltration, necrosis, and apoptotic cells in the liver, and induction of inflammatory markers TNF-α and IL-6 in plasma at the MTDs. These results were fairly consistent between silica NPs and the quartz control, thereby strengthening the argument that silica NPs may act in a similar, thresholded manner. The observed profile is supportive of a secondary genotoxicity mechanism that is driven by inflammation.
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Affiliation(s)
- Thomas R Downs
- The Procter and Gamble Co., Miami Valley Innovation Center, 11810 East Miami River Road, Cincinnati, OH 45252, USA
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Cervantes-Ríos E, Ortiz-Muñiz R, Martínez-Hernández AL, Cabrera-Rojo L, Graniel-Guerrero J, Rodríguez-Cruz L. Malnutrition and infection influence the peripheral blood reticulocyte micronuclei frequency in children. Mutat Res 2012; 731:68-74. [PMID: 22119781 DOI: 10.1016/j.mrfmmm.2011.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Revised: 10/25/2011] [Accepted: 11/10/2011] [Indexed: 05/31/2023]
Abstract
Malnutrition is a serious public health problem that affects approximately one third of all children. Developing countries have the highest incidence of malnourished children, and approximately 60% of deaths that occur in children under five are directly related to malnutrition and associated diseases. The relationship between malnutrition and genetic damage has been widely studied in humans and animal models. The micronucleus (MN) assay is useful in detecting chromosome damage induced by several factors. The aim of this study was to evaluate the effects of infection and malnutrition on the frequency of MN in erythrocytes from the peripheral blood of well-nourished, uninfected (WN) and well-nourished, infected (WNI) children, and moderately malnourished (UNM) and severely malnourished (UNS) children, both with infection, using a flow cytometric analysis technique. The percentage of reticulocytes (RETs) was significantly higher (1.5-fold) in WNI children than well-nourished controls. In addition, the UNS group had a 2.2-fold increase in the percentage of RETs compared to the WNI group. The frequency of micronucleated reticulocytes (MN-RETs) was 2.5 times greater, in WNI group compared to the WN group. These frequencies were significantly higher (1.7- and 2.1-fold) in UNM and UNS, respectively, compared to the WNI group. The results suggest that infection and malnutrition induce DNA damage in children.
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Affiliation(s)
- Elsa Cervantes-Ríos
- Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, Mexico
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Phan N, De Lisio M, Parise G, Boreham DR. Biological effects and adaptive response from single and repeated computed tomography scans in reticulocytes and bone marrow of C57BL/6 mice. Radiat Res 2011; 177:164-75. [PMID: 22059980 DOI: 10.1667/rr2532.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This study investigated the biological effects and adaptive responses induced by single and repeated in vivo computed tomography (CT) scans. We postulated that, through the induction of low-level oxidative stress, repeated low-dose CT scans (20 mGy, 2 days/week, 10 weeks) could protect mice (C57BL/6) from acute effects of high-dose radiation (1 Gy, 2 Gy). The micronucleated reticulocyte (MN-RET) count increased linearly after exposure to single CT scans of doses ranging from 20 to 80 mGy (P = 0.033). Ten weeks of repeated CT scans (total dose 400 mGy) produced a slight reduction in spontaneous MN-RET levels relative to levels in sham CT-scanned mice (P = 0.04). Decreases of nearly 10% in γ-H2AX fluorescence levels were observed in the repeated CT-scanned mice after an in vitro challenge dose of 1 Gy (P = 0.017) and 2 Gy (P = 0.026). Spontaneous apoptosis levels (caspase 3 and 7 activation) were also significantly lower in the repeated CT-scanned mice than the sham CT-scanned mice (P < 0.01). In contrast, mice receiving only a single CT scan showed a 19% elevation in apoptosis (P < 0.02) and a 10% increase in γ-H2AX fluorescence levels after a 2-Gy challenge (P < 0.05) relative to sham CT controls. Overall, repeated CT scans seemed to confer resistance to larger doses in mice, whereas mice exposed to single CT scans exhibited transient genotoxicity, enhanced apoptosis, and characteristics of radiation sensitization.
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Affiliation(s)
- Nghi Phan
- Department of Medical Physics and Applied Radiation Sciences, Nuclear Research Building Room 227, 1280 Main St. West, McMaster University, Hamilton, Ontario, Canada, L8S 4K1.
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Improvement of in vivo genotoxicity assessment: Combination of acute tests and integration into standard toxicity testing. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 723:108-20. [DOI: 10.1016/j.mrgentox.2010.12.005] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/10/2010] [Indexed: 01/15/2023]
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Mao TY, Fu LL, Wang JS. Hypoxic exercise training causes erythrocyte senescence and rheological dysfunction by depressed Gardos channel activity. J Appl Physiol (1985) 2011; 111:382-91. [DOI: 10.1152/japplphysiol.00096.2011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite enhancing cardiopulmonary and muscular fitness, the effect of hypoxic exercise training (HE) on hemorheological regulation remains unclear. This study investigates how HE modulates erythrocyte rheological properties and further explores the underlying mechanisms in the hemorheological alterations. Twenty-four sedentary males were randomly divided into hypoxic (HE; n = 12) and normoxic (NE; n = 12) exercise training groups. The subjects were trained on 60% of maximum work rate under 15% (HE) or 21% (NE) O2condition for 30 min daily, 5 days weekly for 5 wk. The results demonstrated that HE 1) downregulated CD47 and CD147 expressions on erythrocytes, 2) decreased actin and spectrin contents in erythrocytes, 3) reduced erythrocyte deformability under shear flow, and 4) diminished erythrocyte volume changed by hypotonic stress. Treatment of erythrocytes with H2O2that mimicked in vivo prooxidative status resulted in the cell shrinkage, rigidity, and phosphatidylserine exposure, whereas HE enhanced the eryptotic responses to H2O2. However, HE decreased the degrees of clotrimazole to blunt ionomycin-induced shrinkage, rigidity, and cytoskeleton breakdown of erythrocytes, referred to as Gardos effects. Reduced erythrocyte deformability by H2O2was inversely related to the erythrocyte Gardos effect on the rheological function. Conversely, NE intervention did not significantly change resting and exercise erythrocyte rheological properties. Therefore, we conclude that HE rather than NE reduces erythrocyte deformability and volume regulation, accompanied by an increase in the eryptotic response to oxidative stress. Simultaneously, this intervention depresses Gardos channel-modulated erythrocyte rheological functions. Results of this study provide further insight into erythrocyte senescence induced by HE.
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Affiliation(s)
- Tso-Yen Mao
- Graduate Institute of Physical Education, and
| | - Li-Lan Fu
- Department of Athletic Training and Health Science, National Taiwan Sport University; and
| | - Jong-Shyan Wang
- Graduate Institute of Rehabilitation Science, Chang Gung University, Tao-Yuan, Taiwan
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Lynch AM, Sasaki JC, Elespuru R, Jacobson-Kram D, Thybaud V, De Boeck M, Aardema MJ, Aubrecht J, Benz RD, Dertinger SD, Douglas GR, White PA, Escobar PA, Fornace A, Honma M, Naven RT, Rusling JF, Schiestl RH, Walmsley RM, Yamamura E, van Benthem J, Kim JH. New and emerging technologies for genetic toxicity testing. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:205-223. [PMID: 20740635 DOI: 10.1002/em.20614] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 06/02/2010] [Accepted: 06/07/2010] [Indexed: 05/29/2023]
Abstract
The International Life Sciences Institute (ILSI) Health and Environmental Sciences Institute (HESI) Project Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity (IVGT) Testing established an Emerging Technologies and New Strategies Workgroup to review the current State of the Art in genetic toxicology testing. The aim of the workgroup was to identify promising technologies that will improve genotoxicity testing and assessment of in vivo hazard and risk, and that have the potential to help meet the objectives of the IVGT. As part of this initiative, HESI convened a workshop in Washington, DC in May 2008 to discuss mature, maturing, and emerging technologies in genetic toxicology. This article collates the abstracts of the New and Emerging Technologies Workshop together with some additional technologies subsequently considered by the workgroup. Each abstract (available in the online version of the article) includes a section addressed specifically to the strengths, weaknesses, opportunities, and threats associated with the respective technology. Importantly, an overview of the technologies and an indication of how their use might be aligned with the objectives of IVGT are presented. In particular, consideration was given with regard to follow-up testing of positive results in the standard IVGT tests (i.e., Salmonella Ames test, chromosome aberration assay, and mouse lymphoma assay) to add weight of evidence and/or provide mechanism of action for improved genetic toxicity risk assessments in humans.
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Genotoxicity assessment of an energetic propellant compound, 3-nitro-1,2,4-triazol-5-one (NTO). MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 719:35-40. [DOI: 10.1016/j.mrgentox.2010.11.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 11/05/2010] [Accepted: 11/11/2010] [Indexed: 11/22/2022]
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Mughal A, Vikram A, Kushwaha S, Jena GB. Simultaneous use of erythropoietin and prior bleeding enhances the sensitivity of the peripheral blood micronucleus assay. Mutagenesis 2010; 26:331-8. [DOI: 10.1093/mutage/geq099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Fiedler RD, Weiner SK, Schuler M. Evaluation of a modified CD71 MicroFlow method for the flow cytometric analysis of micronuclei in rat bone marrow erythrocytes. Mutat Res 2010; 703:122-9. [PMID: 20723614 DOI: 10.1016/j.mrgentox.2010.08.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 08/06/2010] [Accepted: 08/09/2010] [Indexed: 11/19/2022]
Abstract
The aim of this study was to evaluate a modified flow cytometric method for the quantification of micronuclei in rat bone marrow reticulocytes. The method identified uses the erythrocyte pure fraction from cellulose filtered bone marrow with slight modifications to the widely published MicroFlow(®) method developed by Litron Laboratories, Rochester, NY for the detection of micronuclei in peripheral blood. A number of experiments were conducted to compare the micronucleus induction measured by flow cytometry with traditional microscopic analysis in male rats treated daily for 2 days with appropriate vehicle controls or various doses of cyclophosphamide (CP), mitomycin C (MMC), vinblastine sulfate (VBS), 1,2-dimethylhydrazine (DMH), etoposide (ETO), colchicine (COL), or 4-nitroquinoline-1-oxide (4NQO). In addition, for a subset of chemical we compared the induction of micronuclei in bone marrow and peripheral blood. The results from this study showed a very good correlation of micronucleus frequencies in bone marrow between microscopic analysis and the flow cytometry as well as between blood and bone marrow. In general, micronucleus frequencies of test compound treated animals and inter-animal variability were slightly lower by flow cytometric analysis compared to manual slide analysis. The data presented in this study support the use of the CD71 flow method for the analysis of micronuclei in rat bone marrow and also suggest that peripheral blood may be equally as sensitive as bone marrow in detecting a micronucleus response in short term studies.
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Mughal A, Vikram A, Ramarao P, Jena G. Micronucleus and comet assay in the peripheral blood of juvenile rat: Establishment of assay feasibility, time of sampling and the induction of DNA damage. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2010; 700:86-94. [DOI: 10.1016/j.mrgentox.2010.05.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 04/02/2010] [Accepted: 05/22/2010] [Indexed: 11/25/2022]
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A strategy to study genotoxicity: application to aquatic toxins, limits and solutions. Anal Bioanal Chem 2010; 397:1715-22. [DOI: 10.1007/s00216-010-3699-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 03/24/2010] [Accepted: 03/29/2010] [Indexed: 11/25/2022]
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Kalantari H, Dashtearjandi AA, Kalantar E. Genotoxicity study of Hypiran and Chamomilla herbal drugs determined by in vivo supervital micronucleus assay with mouse peripheral reticulocytes. ACTA BIOLOGICA HUNGARICA 2009; 60:177-83. [PMID: 19584027 DOI: 10.1556/abiol.60.2009.2.5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The growth in popularity of Over The Counter (OTC) of medicinal products or other natural sources have taken a very large share of healthcare system therefore it is essential to determine their safety as for as public health is concerned.In this study Maximum Tolerated Dose (MTD) was obtained according to CSGMT protocol presented by the Environmental Mutagen Society of Japan. The positive group received mitomycin C in dose of 0.5 mg/kg. The peripheral blood samples before treatment (zero time) were considered as negative control. The MTD of Hypiron was 12 ml/kg and for Chamomilla was 10 ml/kg. Doses of MTD, 1/2 MTD and 1/4 MTD were considered for test groups. Then blood samples were prepared 48 hours after first administration of drugs and kept on precoated Acridine orange slides. The scoring of micronucleated reticulocytes were carried out per 2000 counted reticulocytes in each slide by fluorescent microscope. The results were statistically analyzed. Results of Hypiran were compared with negative control group and the P value was P > 0.05, but the p value of Chamomilla was P < 0.05. Also, the p value of Hypiran and Chamomilla compared with historical negative control group was less, therefore Chamomilla herbal drog can be classified as equivocul category of genotoxicity and Hypiran did not show genotoxicity.
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Affiliation(s)
- H Kalantari
- School of Pharmacy , Ahwaz Jundishapur University of Medical Sciences, Ahwaz, Iran.
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Dertinger SD, Bemis JC, Phonethepswath S, Tsai Y, Nowak I, Hyrien O, Palis J, Chen Y. Reticulocyte and micronucleated reticulocyte responses to gamma irradiation: effect of age. Mutat Res 2009; 675:77-80. [PMID: 19386252 DOI: 10.1016/j.mrgentox.2009.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 02/03/2009] [Accepted: 02/04/2009] [Indexed: 11/28/2022]
Abstract
The effect of age on the formation of radiation-induced micronucleated reticulocytes (MN-RETs) and reticulocytes (RETs) was investigated by exposing female C57BL/6J mice to graded doses of gamma rays from a (137)Cs source. Age at time of irradiation was 6, 16, or 32 weeks, and doses ranged from 0.5 to 3 Gy. A flow cytometric technique based on anti-CD71 labeling was used to measure RET and MN-RET frequencies in blood specimens collected 43 h post-irradiation. Mean RET frequencies declined in a dose-dependent manner for each age group. There was only one significant difference among the ages, that is, %RETs were not significantly reduced in the oldest animals at 0.5 Gy, whereas this dose did have a significant effect on the other age groups. MN-RET data were more complex. Age was observed to influence the baseline frequency of MN-RET, with the oldest mice exhibiting a significantly higher mean value. Each group's %MN-RETs values increased up to 1 Gy, but past this dose the frequencies plateaued or decreased. Age was observed to influence micronucleus frequency, with older mice exhibiting higher mean MN-RET values, especially at the high doses where the response was saturated (2-3 Gy). We hypothesize that these dissimilar responses can largely be explained by an age-related down-regulation of apoptosis whereby younger animals eliminate damaged bone marrow erythroid precursors with a greater efficiency compared with aged mice.
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Vikram A, Tripathi D, Pawar A, Ramarao P, Jena G. Pre-bled-young-rats in genotoxicity testing: A model for peripheral blood micronucleus assay. Regul Toxicol Pharmacol 2008; 52:147-57. [DOI: 10.1016/j.yrtph.2008.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2008] [Revised: 07/09/2008] [Accepted: 07/23/2008] [Indexed: 11/25/2022]
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Van Miert E, Vanscheeuwijck P, Meurrens K, Gomm W, Terpstra PM. Evaluation of the micronucleus assay in bone marrow and peripheral blood of rats for the determination of cigarette mainstream-smoke activity. Mutat Res 2008; 652:131-8. [PMID: 18406658 DOI: 10.1016/j.mrgentox.2008.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Revised: 12/18/2007] [Accepted: 01/26/2008] [Indexed: 11/23/2022]
Abstract
The mammalian in vivo micronucleus assay is widely used as part of the genotoxicity testing battery required during the development of new drugs. As such, the in vivo micronucleus assay has been used in a battery of assays for the assessment of cigarette ingredients or design modifications to help ensure that there is no increase in risk or any new risk introduced by these additions or modifications. The present series of studies was conducted to optimize and evaluate this assay for the assessment of the effects of mainstream smoke on the micronucleus frequency in the bone marrow and peripheral blood of rats. In a first experiment, the optimal conditions for performing the micronucleus assay in these tissues were determined. This was done by use of two compounds known for their micronucleus-inducing activity, i.e., the clastogen cyclophosphamide and the aneugen colchicine. In a second experiment, the effects of tube restraint on untreated control rats were investigated. In a third experiment, the optimal conditions were used to assess the clastogenic/aneugenic activity of cigarette smoke in Sprague-Dawley rats. The rat micronucleus assay in both bone marrow and peripheral blood is able to detect clastogenic and aneugenic activity. The flow cytometric determination of micronucleated cells in rat blood is at least as sensitive as determinations in bone marrow. No statistically significant differences were observed in micronucleus frequencies between rats with and without the additional stress of tube restraint; however, the cautious approach would be to use a fresh-air-exposed group (with tube restraint) as the negative control in inhalation experiments. Using the conditions identified as optimal in the above-mentioned experiments, the micronucleus assay was not able to detect effects induced by smoke from conventional cigarettes. Nevertheless, the micronucleus assay will remain a valuable tool as part of a testing battery used to investigate possible adverse effects related to product modifications.
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Affiliation(s)
- Erik Van Miert
- Philip Morris Research Laboratories bvba, Leuven, Belgium.
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Hotchkiss CE, Bishop ME, Dertinger SD, Slikker W, Moore MM, Macgregor JT. Flow cytometric analysis of micronuclei in peripheral blood reticulocytes IV: an index of chromosomal damage in the rhesus monkey (Macaca mulatta). Toxicol Sci 2008; 102:352-8. [PMID: 18211907 DOI: 10.1093/toxsci/kfn013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We report evaluation in rhesus monkeys of a flow cytometric procedure (MicroFlow) that has previously been shown to allow assessment of micronucleated reticulocytes (MN-RETs) in the peripheral blood of rats and dogs. Reticulocytes (RETs) were labeled with anti-CD71-fluorescein isothiocyanate, DNA was stained with propidium iodide using RNase treatment, and anti-CD61-phycoerythrin was used to reduce interference from platelets. Flow cytometric data were compared with microscopic scores of peripheral blood and bone marrow using standard acridine orange staining. A single iv administration of cyclophosphamide (CP, 5 mg/kg) induced an approximately 10-fold increase in blood MN-RET frequency, with the peak occurring 2 days after administration. After daily CP treatment to approximate a steady-state condition, the frequency of MN-RETs in peripheral blood was approximately 25% of that in bone marrow, indicating strong selection against MN-RETs. Nonetheless, CP-treated animals exhibited markedly elevated blood MN-RET values (2.45-3.99%, n = 3; compared to a mean baseline of 0.12%, n = 6). These measurements closely reflected the increased frequencies observed in the bone marrow compartment (Spearman correlation coefficient = 0.9856, n = 6). These data suggest that MN-RET measurements in blood are suitable for assessing chemical-induced chromosomal damage and can be readily integrated into routine toxicity tests, allowing genotoxicity data to be obtained as an integral part of toxicity evaluations. Microscopy-based scoring is challenging due to the low frequency of RETs and MN-RET in monkeys, but sufficient numbers of cells are easily scored with the flow cytometric procedure.
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Harper SB, Dertinger SD, Bishop ME, Lynch AM, Lorenzo M, Saylor M, MacGregor JT. Flow Cytometric Analysis of Micronuclei in Peripheral Blood Reticulocytes III. An Efficient Method of Monitoring Chromosomal Damage in the Beagle Dog. Toxicol Sci 2007; 100:406-14. [PMID: 17872896 DOI: 10.1093/toxsci/kfm241] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Erythrocyte-based micronucleus tests have traditionally analyzed bone marrow because splenic filtration in most species removes micronucleated cells from peripheral blood. We have evaluated a flow cytometric method for monitoring micronucleated reticulocyte frequencies (%MN-RET) in the peripheral blood of beagle dogs treated with cyclophosphamide (CP) and have found that analysis of micronucleated reticulocytes (MN-RETs) in peripheral blood is a suitable surrogate for bone marrow analysis. The three-color flow cytometric method uses anti-CD71 labeling to identify reticulocytes and Plasmodium berghei-containing erythrocytes as a calibration standard. The spontaneous %MN-RET determined by flow cytometry was 0.31 +/- 0.09% (n = 22) for peripheral blood, compared with 0.38 +/- 0.13% (SD, n = 12) for bone marrow, and 0.27 +/- 0.08% (n = 12) for peripheral blood by microscopic scoring with acridine orange staining. The kinetics of appearance and disappearance of MN-RETs in blood were determined by collecting daily samples after iv treatment with CP. The maximum frequency occurred approximately 48 h after dosing. Frequencies of MN-RETs in peripheral blood at steady state following daily CP treatment were 55-68% of corresponding bone marrow values assessed by microscopy and 55-112% as assessed by flow cytometry. This difference is presumably due to splenic removal, which appears slightly less stringent than that previously reported for CP-treated Sprague-Dawley rats. Responses in bone marrow and peripheral blood were highly correlated and similar to or greater than those reported in mice and rats at equitoxic doses.
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Affiliation(s)
- Susan B Harper
- Department of Veterans Affairs, Washington, DC 20422, USA
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Witt KL, Livanos E, Kissling GE, Torous DK, Caspary W, Tice RR, Recio L. Comparison of flow cytometry- and microscopy-based methods for measuring micronucleated reticulocyte frequencies in rodents treated with nongenotoxic and genotoxic chemicals. Mutat Res 2007; 649:101-13. [PMID: 17869571 PMCID: PMC2234598 DOI: 10.1016/j.mrgentox.2007.08.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 08/06/2007] [Accepted: 08/07/2007] [Indexed: 11/24/2022]
Abstract
The development of automated flow cytometric (FCM) methods for evaluating micronucleus (MN) frequencies in erythrocytes has great potential for improving the sensitivity, reproducibility, and throughput of the traditional in vivo rodent MN assay that uses microscopy-based methods for data collection. Although some validation studies of the FCM evaluation methods have been performed, a comprehensive comparison of these two data collection methods under routine testing conditions with a variety of compounds in multiple species has not been conducted. Therefore, to determine if FCM evaluation of MN frequencies in rodents was an acceptable alternative to traditional manual scoring methods in our laboratory, we conducted a comparative evaluation of MN-reticulocyte (MN-RET) frequencies determined by FCM- and microscopy-based scoring of peripheral blood and bone marrow samples from B6C3F1 mice and Fisher 344 rats. Four known inducers of MN (cyclophosphamide, ethyl methanesulfonate, vincristine sulfate, acrylamide) were assayed in bone marrow and peripheral blood of both mice and rats. In addition, MN-RET frequencies were measured in bone marrow (microscopy) and peripheral blood (FCM) of mice treated with five nongenotoxic chemicals (S-adenosylmethionine chloride, cefuroxime, diphenolic acid, 3-amino-6-methylphenol, pentabromodiphenyl oxide). No significant differences were observed between results obtained by the two methods in either species. These results support the use of FCM for determining MN-RET frequency in rodents after chemical exposure.
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Affiliation(s)
- Kristine L Witt
- Environmental Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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Vikram A, Ramarao P, Jena G. Prior bleeding enhances the sensitivity of peripheral blood and bone marrow micronucleus tests in rats. Mutagenesis 2007; 22:287-91. [PMID: 17548865 DOI: 10.1093/mutage/gem015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The rat peripheral blood micronucleus (MN) assay is not considered to be a sufficient biomarker of genotoxin exposure due to the selective elimination of micronucleated cells from peripheral circulation by the spleen. However, several recent reports suggest that peripheral blood reticulocytes of rats may represent a suitable cell population for use in the MN assay. The MN assay in rats with prior bleeding was thus conducted to determine the sensitivity of the bioassay. Hirai et al. reported that prior bleeding enhances the sensitivity of the in vivo MN test in mice. Based on these findings, the rat was used as a model to see the effect of prior bleeding on the sensitivity of the peripheral blood and bone marrow MN assays. In the present experiment, young male Sprague-Dawley (SD) rats ranging in age from 21 to 24 days were used. However, for the comparison of strain-specific induction of MN, Wistar rats were used. The kinetics of MN formation were investigated in adult, young bled and non-bled SD rats treated with cyclophosphamide (CP). For the MN kinetic study, CP was administered intraperitoneally 2 h after bleeding and sampling was done at intervals of 12, 24, 36, 48 and 96 h after chemical administration. Significant increases in MN induction activity in both bone marrow and peripheral blood were observed with prior bleeding. To further validate the influence of prior bleeding in the induction of MN frequency, two other known genotoxins (chlorambucil and mitomycin C) were used. It was concluded that prior bleeding can significantly increase the sensitivity of MN induction in both bone marrow and peripheral blood of rats compared with non-bled animals. Once validated, this model may be suitable for detecting different genotoxins, especially weak and marginally active clastogens.
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Affiliation(s)
- Ajit Vikram
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, Punjab-160062, India
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Dertinger SD, Miller RK, Brewer K, Smudzin T, Torous DK, Roberts DJ, Avlasevich SL, Bryce SM, Sugunan S, Chen Y. Automated human blood micronucleated reticulocyte measurements for rapid assessment of chromosomal damage. Mutat Res 2007; 626:111-9. [PMID: 17059891 PMCID: PMC1796663 DOI: 10.1016/j.mrgentox.2006.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 09/08/2006] [Accepted: 09/11/2006] [Indexed: 01/10/2023]
Abstract
This study evaluated the utility of human blood micronucleated reticulocyte (MNCD71+) frequency measurement as a cytogenetic damage biomarker. The analytical methodology was flow cytometry in conjunction with a previously described three color fluorescence labeling technique that includes anti-CD71 to focus analyses on the most immature fraction of reticulocytes [S.D. Dertinger, K. Camphausen, J.T. MacGregor, M.E. Bishop, D.K. Torous, S. Avlasevich, et al., Three-color labeling method for flow cytometric measurement of cytogenetic damage in rodent and human blood, Environ. Mol. Mutagen. 44 (2004) 427-435]. Blood specimens from 50 self-reported healthy adult volunteers were studied. In addition to MNCD71+ measurements, blood plasma folate and B12 levels were assessed, since these variables tend to influence other indices of cytogenetic damage. Time-course data are also provided for 10 cancer patients undergoing treatment. For these subjects, frequency of MNCD71+ was measured immediately before therapy, and daily during the first week of chemotherapy and/or fractionated radiotherapy. For the group of healthy volunteers, the variables of age, and folate and B12 levels demonstrated no significant effect on MNCD71+ frequency. In addition, no difference was observed between pre-treatment MNCD71+ values for cancer patients compared with healthy volunteers. Regarding chemotherapy and/or partial body radiotherapy, elevated frequencies were observed upon initiation of treatment for 9 of the 10 patients studied. Maximal effects were observed 3-5 days following initiation of therapy. The largest increases in frequency of MNCD71+ (up to 25.9-fold) were observed in those patients exposed to anti-neoplastic drugs, presumably due to the systemic red marrow exposure provided by these agents. Taken together, these data support the hypothesis that the MNCD71+ endpoint represents a valuable biomarker of cytogenetic damage that does not require cell culture or microscopy-based scoring.
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Affiliation(s)
- Stephen D Dertinger
- Litron Laboratories, 200 Canal View Boulevard, Rochester, NY, United States.
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Hayashi M, MacGregor JT, Gatehouse DG, Blakey DH, Dertinger SD, Abramsson-Zetterberg L, Krishna G, Morita T, Russo A, Asano N, Suzuki H, Ohyama W, Gibson D. In vivo erythrocyte micronucleus assay III. Validation and regulatory acceptance of automated scoring and the use of rat peripheral blood reticulocytes, with discussion of non-hematopoietic target cells and a single dose-level limit test. Mutat Res 2006; 627:10-30. [PMID: 17157053 DOI: 10.1016/j.mrgentox.2006.08.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 07/31/2006] [Accepted: 08/14/2006] [Indexed: 10/23/2022]
Abstract
The in vivo micronucleus assay working group of the International Workshop on Genotoxicity Testing (IWGT) discussed new aspects in the in vivo micronucleus (MN) test, including the regulatory acceptance of data derived from automated scoring, especially with regard to the use of flow cytometry, the suitability of rat peripheral blood reticulocytes to serve as the principal cell population for analysis, the establishment of in vivo MN assays in tissues other than bone marrow and blood (for example liver, skin, colon, germ cells), and the biological relevance of the single-dose-level test. Our group members agreed that flow cytometric systems to detect induction of micronucleated immature erythrocytes have advantages based on the presented data, e.g., they give good reproducibility compared to manual scoring, are rapid, and require only small quantities of peripheral blood. Flow cytometric analysis of peripheral blood reticulocytes has the potential to allow monitoring of chromosome damage in rodents and also other species as part of routine toxicology studies. It appears that it will be applicable to humans as well, although in this case the possible confounding effects of splenic activity will need to be considered closely. Also, the consensus of the group was that any system that meets the validation criteria recommended by the IWGT (2000) should be acceptable. A number of different flow cytometric-based micronucleus assays have been developed, but at the present time the validation data are most extensive for the flow cytometric method using anti-CD71 fluorescent staining especially in terms of inter-laboratory collaborative data. Whichever method is chosen, it is desirable that each laboratory should determine the minimum sample size required to ensure that scoring error is maintained below the level of animal-to-animal variation. In the second IWGT, the potential to use rat peripheral blood reticulocytes as target cells for the micronucleus assay was discussed, but a consensus regarding acceptability for regulatory purposes could not be reached at that time. Subsequent validation efforts, combined with accumulated published data, demonstrate that blood-derived reticulocytes from rats as well as mice are acceptable when young reticulocytes are analyzed under proper assay protocol and sample size. The working group reviewed the results of micronucleus assays using target cells/tissues other than hematopoietic cells. We also discussed the relevance of the liver micronucleus assay using young rats, and the importance of understanding the maturation of enzyme systems involved in the processes of metabolic activation in the liver of young rats. Although the consensus of the group was that the more information with regard to the metabolic capabilities of young rats would be useful, the published literature shows that young rats have sufficient metabolic capacity for the purposes of this assay. The use of young rats as a model for detecting MN induction in the liver offers a good alternative methodology to the use of partial hepatectomy or mitogenic stimulation. Additional data obtained from colon and skin MN models have been integrated into the data bases, enhancing confidence in the utility of these models. A fourth topic discussed by the working group was the regulatory acceptance of the single-dose-level assay. There was no consensus regarding the acceptability of a single dose level protocol when dose-limiting toxicity occurs. The use of a single dose level can lead to problems in data interpretation or to the loss of animals due to unexpected toxicity, making it necessary to repeat the study with additional doses. A limit test at a single dose level is currently accepted when toxicity is not dose-limiting.
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Affiliation(s)
- Makoto Hayashi
- Division of Genetics & Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga Setagaya-ku, Tokyo 158-8501, Japan.
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