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Alves-Pimenta S, Félix L, Colaço B, Oliveira PA, Venâncio C. Guidelines on Developmental Toxicity Tests: Brief Insights. Methods Mol Biol 2024; 2753:39-65. [PMID: 38285333 DOI: 10.1007/978-1-0716-3625-1_2] [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] [Indexed: 01/30/2024]
Abstract
Developmental toxicology is a constantly evolving research field which needs to attend to a complex underlying regulatory network. In order to ensure human health and environmental safety, new substances have to be tested for toxic effects on reproduction and development, before being commercialized. Traditional in vivo mammalian models represent the intricacy of human development and provide more adequately an assessment of the interaction of chemical compounds with the reproductive system. However, in the last years, the directives are to reduce the use of vertebrate animals, promoting their use only as a last resort. Consequently, the interest on the development and validation of alternative tests, able to cover the various aspects of the reproductive cycle, has significantly increased. Reproductive toxicity is probably the most difficult endpoint to be replaced by alternative assays, since it should provide information on mechanism interactions essential for female and male fertility and also knowledge on the animal development during the first phases of its life cycle. This complexity explains the slow progress in implementing alternative models for reproductive toxicity safety assays. Alternative test models may be based on in vitro systems and nonmammalian animal models. Many biological processes have been successfully addressed using in vitro models, opening the possibility to study the interference of teratogenic compounds. Their validation and implementation have lagged behind, in part because of difficulties in establishing their predictability. Nevertheless, the advance toward the process of validation is crucial to replace and reduce the use of living animals. Based on the present state of the art, it is not probable that such testing strategies will completely replace the need to assess reproductive toxicity in vivo in the near future, but they will contribute to reduce animal tests and will provide important information. In this chapter, the approved guidelines for standard methods and alternative methods, according to their regulatory and scientific status, are enumerated and briefly described.
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Affiliation(s)
- Sofia Alves-Pimenta
- Department of Animal Science, School of Agrarian and Veterinary Sciences (ECAV), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Animal and Veterinary Research Centre (CECAV), Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
| | - Luís Félix
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Institute for Innovation, Capacity Building and Sustainability of Agri-food Production (Inov4Agro), University of Trás-os Montes and Alto Douro (UTAD), Vila Real, Portugal
| | - Bruno Colaço
- Department of Animal Science, School of Agrarian and Veterinary Sciences (ECAV), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Animal and Veterinary Research Centre (CECAV), Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
| | - Paula A Oliveira
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Institute for Innovation, Capacity Building and Sustainability of Agri-food Production (Inov4Agro), University of Trás-os Montes and Alto Douro (UTAD), Vila Real, Portugal
- Department of Veterinary Sciences, School of Agrarian and Veterinary Sciences (ECAV), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
| | - Carlos Venâncio
- Department of Animal Science, School of Agrarian and Veterinary Sciences (ECAV), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.
- Institute for Innovation, Capacity Building and Sustainability of Agri-food Production (Inov4Agro), University of Trás-os Montes and Alto Douro (UTAD), Vila Real, Portugal.
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Hwang YS, So D, Lee M, Yoon J, Reipa V, Tona A, Yi F, Nelson BC, LaVan DA, Hackley VA, Daar IO, Cho TJ. Polyethyleneimine/polyethylene glycol-conjugated gold nanoparticles as nanoscale positive/negative controls in nanotoxicology: testing in frog embryo teratogenesis assay- Xenopus and mammalian tissue culture system. Nanotoxicology 2023; 17:94-115. [PMID: 36919473 PMCID: PMC10471858 DOI: 10.1080/17435390.2023.2187322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 12/20/2022] [Accepted: 02/28/2023] [Indexed: 03/16/2023]
Abstract
Despite the great potential of using positively charged gold nanoparticles (AuNPs) in nanomedicine, no systematic studies have been reported on their synthesis optimization or colloidal stability under physiological conditions until a group at the National Institute of Standards and Technology recently succeeded in producing remarkably stable polyethyleneimine (PEI)-coated AuNPs (Au-PEI). This improved version of Au-PEI (Au-PEI25kB) has increased the demand for toxicity and teratogenicity information for applications in nanomedicine and nanotoxicology. In vitro assays for Au-PEI25kB in various cell lines showed substantial active cytotoxicity. For advanced toxicity research, the frog embryo teratogenesis assay-Xenopus (FETAX) method was employed in this study. We observed that positively-charged Au-PEI25kB exhibited significant toxicity and teratogenicity, whereas polyethylene glycol conjugated AuNPs (Au-PEG) used as comparable negative controls did not. There is a characteristic avidity of Au-PEI25kB for the jelly coat, the chorionic envelope (also known as vitelline membrane) and the cytoplasmic membrane, as well as a barrier effect of the chorionic envelope observed with Au-PEG. To circumvent these characteristics, an injection-mediated FETAX approach was utilized. Like treatment with the FETAX method, the injection of Au-PEI25kB severely impaired embryo development. Notably, the survival/concentration curve that was steep when the standard FETAX approach was employed became gradual in the injection-mediated FETAX. These results suggest that Au-PEI25kB may be a good candidate as a nanoscale positive control material for nanoparticle analysis in toxicology and teratology.
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Affiliation(s)
- Yoo-Seok Hwang
- National Cancer Institute, Frederick, Maryland 21702, United States
| | - Daeho So
- National Cancer Institute, Frederick, Maryland 21702, United States
| | - Moonsup Lee
- National Cancer Institute, Frederick, Maryland 21702, United States
| | - Jaeho Yoon
- National Cancer Institute, Frederick, Maryland 21702, United States
| | - Vytas Reipa
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Alessandro Tona
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Feng Yi
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Bryant C. Nelson
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - David A. LaVan
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Vincent A. Hackley
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Ira O. Daar
- National Cancer Institute, Frederick, Maryland 21702, United States
| | - Tae Joon Cho
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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Battistoni M, Bacchetta R, Di Renzo F, Metruccio F, Moretto A, Menegola E. Modified Xenopus laevis approach (R-FETAX) as an alternative test for the evaluation of foetal valproate spectrum disorder. Reprod Toxicol 2021; 107:140-149. [PMID: 34923091 DOI: 10.1016/j.reprotox.2021.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/25/2021] [Accepted: 12/09/2021] [Indexed: 10/19/2022]
Abstract
In compliance to animal welfare 3Rs principle there is a great demand for refined tests alternative to classical mammal teratogenicity tests. We propose a refined alternative amphibian method (R-FETAX) to evaluate chemical induced embryotoxicity. The human foetal valproate spectrum disorder (FVSD) characteristics are morphological defects (including cranio-facial, neural tube defects) and behavioural alterations due to valproate (VPA) exposure in pregnancy. Vertebrate assays to evaluate FVSD include classical and alternative mammal (implying adult sacrifice), and non-mammal developmental models (zebrafish, amphibians, chick). Among these latter only zebrafish assays report in the same test both morphological and behavioural examinations. Compared to zebrafish, the amphibian Xenopus laevis excels having a more comparable organ development and morphology to mammalian systems. We used X. laevis embryos exposed during developmental specific windows to VPA therapeutic concentrations. Different VPA effects were observed depending on the exposure window: concentration-related embryo-lethal and teratogenic effects (neural tube, facial, tail defects) were observed in groups exposed at the organogenetic phylotypic stages. Neurobehavioral deficits were described using a functional swimming test at the highest VPA concentration exposure during the phylotypic stages and at any concentration during neurocognitive competent stages. Malformations were compared to those obtained in a mammalian assay (the rat post-implantation whole embryo culture method, WEC), that we used in the past to evaluate VPA teratogenicity. R-FETAX and WEC data were modelled and their relative sensitivity was calculated. We suggest the amphibian R-FETAX as a refined windowed alternative test for the evaluation of chemicals inducing both morphological and behavioural anomalies, including VPA.
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Affiliation(s)
- Maria Battistoni
- Università Degli Studi di Milano, Department of Physics Aldo Pontremoli, via Celoria, 16-20133, Milan, Italy; Università Degli Studi di Milano, Department of Environmental Science and Policy, via Celoria, 26-20133, Milan, Italy.
| | - Renato Bacchetta
- Università Degli Studi di Milano, Department of Environmental Science and Policy, via Celoria, 26-20133, Milan, Italy.
| | - Francesca Di Renzo
- Università Degli Studi di Milano, Department of Environmental Science and Policy, via Celoria, 26-20133, Milan, Italy.
| | | | - Angelo Moretto
- Università Degli Studi di Milano, Department of Biomedical and Clinical Sciences "L. Sacco", via GB Grassi, 74- 20159, Milan, Italy.
| | - Elena Menegola
- Università Degli Studi di Milano, Department of Environmental Science and Policy, via Celoria, 26-20133, Milan, Italy.
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Li M, Brokaw A, Furuta AM, Coler B, Obregon-Perko V, Chahroudi A, Wang HY, Permar SR, Hotchkiss CE, Golos TG, Rajagopal L, Adams Waldorf KM. Non-human Primate Models to Investigate Mechanisms of Infection-Associated Fetal and Pediatric Injury, Teratogenesis and Stillbirth. Front Genet 2021; 12:680342. [PMID: 34290739 PMCID: PMC8287178 DOI: 10.3389/fgene.2021.680342] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 05/25/2021] [Indexed: 12/25/2022] Open
Abstract
A wide array of pathogens has the potential to injure the fetus and induce teratogenesis, the process by which mutations in fetal somatic cells lead to congenital malformations. Rubella virus was the first infectious disease to be linked to congenital malformations due to an infection in pregnancy, which can include congenital cataracts, microcephaly, hearing impairment and congenital heart disease. Currently, human cytomegalovirus (HCMV) is the leading infectious cause of congenital malformations globally, affecting 1 in every 200 infants. However, our knowledge of teratogenic viruses and pathogens is far from complete. New emerging infectious diseases may induce teratogenesis, similar to Zika virus (ZIKV) that caused a global pandemic in 2016-2017; thousands of neonates were born with congenital microcephaly due to ZIKV exposure in utero, which also included a spectrum of injuries to the brain, eyes and spinal cord. In addition to congenital anomalies, permanent injury to fetal and neonatal organs, preterm birth, stillbirth and spontaneous abortion are known consequences of a broader group of infectious diseases including group B streptococcus (GBS), Listeria monocytogenes, Influenza A virus (IAV), and Human Immunodeficiency Virus (HIV). Animal models are crucial for determining the mechanism of how these various infectious diseases induce teratogenesis or organ injury, as well as testing novel therapeutics for fetal or neonatal protection. Other mammalian models differ in many respects from human pregnancy including placentation, labor physiology, reproductive tract anatomy, timeline of fetal development and reproductive toxicology. In contrast, non-human primates (NHP) most closely resemble human pregnancy and exhibit key similarities that make them ideal for research to discover the mechanisms of injury and for testing vaccines and therapeutics to prevent teratogenesis, fetal and neonatal injury and adverse pregnancy outcomes (e.g., stillbirth or spontaneous abortion). In this review, we emphasize key contributions of the NHP model pre-clinical research for ZIKV, HCMV, HIV, IAV, L. monocytogenes, Ureaplasma species, and GBS. This work represents the foundation for development and testing of preventative and therapeutic strategies to inhibit infectious injury of human fetuses and neonates.
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Affiliation(s)
- Miranda Li
- Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, United States
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - Alyssa Brokaw
- Department of Global Health, University of Washington, Seattle, WA, United States
| | - Anna M. Furuta
- Department of Global Health, University of Washington, Seattle, WA, United States
| | - Brahm Coler
- Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, United States
| | - Veronica Obregon-Perko
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Ann Chahroudi
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States
- Center for Childhood Infections and Vaccines of Children’s Healthcare of Atlanta and Emory University, Atlanta, GA, United States
| | - Hsuan-Yuan Wang
- Department of Pediatrics, Weill Cornell Medicine, New York, NY, United States
| | - Sallie R. Permar
- Department of Pediatrics, Weill Cornell Medicine, New York, NY, United States
| | - Charlotte E. Hotchkiss
- Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Thaddeus G. Golos
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, United States
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle, WA, United States
- Department of Pediatrics, University of Washington, Seattle, WA, United States
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Kristina M. Adams Waldorf
- Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, United States
- Department of Global Health, University of Washington, Seattle, WA, United States
- Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Babalola OO, Truter JC, Van Wyk JH. Lethal and Teratogenic Impacts of Imazapyr, Diquat Dibromide, and Glufosinate Ammonium Herbicide Formulations Using Frog Embryo Teratogenesis Assay-Xenopus (FETAX). ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 80:708-716. [PMID: 32901337 DOI: 10.1007/s00244-020-00756-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 08/21/2020] [Indexed: 06/11/2023]
Abstract
Globally, amphibians are experiencing widespread abnormalities and population declines. One potential contributor to these challenges is the use of pesticides, particularly aquatic herbicides applied to aquatic habitats inhabited by amphibians. Critical issues of concern are the potential toxicity and teratogenicity of these herbicides towards amphibians. Using the FETAX protocol, three globally used formulations, including diquat dibromide (Midstream), glufosinate ammonium (Basta), and imazapyr (Arsenal), were assessed for embryotoxicity, teratogenicity, and growth inhibition. Developing Xenopus laevis embryos were exposed for 96 h at concentrations of 0.5-3.0 mg/L, 1.6-3.0 mg/L, and 20-45 mg/L for Midstream, Basta, and Arsenal respectively. The 96-h LC50 estimates were 0.83 mg/L acid equivalent (a.e.), 36 mg/L a.e., and 2.2 mg/L a.e., whereas the EC50 estimates were 0.24 mg/L a.e., 28.13 mg/L a.e., and 2.01 mg/L a.e. for the Midstream, Arsenal, and Basta formulations, respectively. These two estimates produced Teratogenic Index of 3.5, 1.3, and 1.1 for Midstream, Arsenal, and Basta, respectively, indicating a high risk of malformation induction by Midstream and moderate risk for Arsenal. Regarding growth inhibition, lowest observable effect concentrations of 0.5 mg/L, 25 mg/L, and 2.0 mg/L were computed for Midstream, Arsenal, and Basta, respectively, producing the minimum concentration inhibiting growth (MCIG) ratios of 0.62, 0.69, and 0.89 for the three formulations. These MICG values are higher than the standard 0.30 growth inhibitors benchmark, suggesting that the formulations are not growth inhibitors at the evaluated concentrations. This study provides evidence of the embryotoxic and teratogenic status of Midstream and the embryotoxicity of Basta. There is a need to further characterise the physiological and ecological impacts of these formulations to ensure responsible use and the safety of amphibians and other wildlife.
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Affiliation(s)
- Oluwaseun Olusegun Babalola
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa.
- Zoology and Environmental Biology, Lagos State University, Ojo, Lagos, Nigeria.
| | - Johannes Christoff Truter
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- Department of Paraclinical Sciences, Faculty of Veterinary Sciences, University of Pretoria, Pretoria, South Africa
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Battistoni M, Bacchetta R, Di Renzo F, Metruccio F, Menegola E. Effect of nano-encapsulation of β-carotene on Xenopus laevis embryos development (FETAX). Toxicol Rep 2020; 7:510-519. [PMID: 32346517 PMCID: PMC7182698 DOI: 10.1016/j.toxrep.2020.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/08/2020] [Accepted: 04/14/2020] [Indexed: 01/01/2023] Open
Abstract
Vitamin A plays a vital role during embryo development as most precursor of embryonic retinoic acid, a key morphogen during embryogenesis. Carotenoids, including β-carotene, are important vegetal source of Vitamin A and in contrast to teratogenic potential of animal-derived retinoids, β-carotene is usually considered freed from embryotoxic effects and supplements in pregnancy with β-carotene are suggested. The aim of the present work is to evaluate the effect of bulk and nano-encapsulated β-carotene on embryo development, by using the animal model Frog Embryo Teratogenesis Assay: Xenopus- FETAX. Xenopus laevis embryos were exposed from late gastrula till pharyngula (the phylotypic stage for vertebrates) to the concentrations of BULK β-carotene 150-3000 ng/mL and NANO β-carotene 0.75-30 ng/mL. At pharyngula stage, some embryos were processed for whole mount neural crest cell immunostaining, while others embryos were allowed to develop till tadpole for morphological and histological evaluation of neural crest cells-derived structures. In this model, the nano-encapsulated β-carotene induced specific malformations at craniofacial and eye level, while the bulk formulation only induced developmental delays. Finally, the applied alternative animal model resulted a rapid and sensitive screening method able to re-evaluate the teratogenic profile of nano-encapsulated micronutrients.
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Affiliation(s)
- Maria Battistoni
- Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
| | - Renato Bacchetta
- Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
| | - Francesca Di Renzo
- Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
| | | | - Elena Menegola
- Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
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Bonfanti P, Colombo A, Saibene M, Fiandra L, Armenia I, Gamberoni F, Gornati R, Bernardini G, Mantecca P. Iron nanoparticle bio-interactions evaluated in Xenopus laevis embryos, a model for studying the safety of ingested nanoparticles. Nanotoxicology 2019; 14:196-213. [DOI: 10.1080/17435390.2019.1685695] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Patrizia Bonfanti
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milano, Italy
| | - Anita Colombo
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milano, Italy
| | - Melissa Saibene
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milano, Italy
| | - Luisa Fiandra
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milano, Italy
| | - Ilaria Armenia
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Federica Gamberoni
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Rosalba Gornati
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Giovanni Bernardini
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Paride Mantecca
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milano, Italy
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Babalola OO, Truter JC, van Wyk JH. Mortality, teratogenicity and growth inhibition of three glyphosate formulations using Frog Embryo Teratogenesis Assay-Xenopus. J Appl Toxicol 2019; 39:1257-1266. [PMID: 31168868 DOI: 10.1002/jat.3811] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 03/28/2019] [Accepted: 03/28/2019] [Indexed: 12/17/2023]
Abstract
Ample evidence around the world exists suggesting a link between exposure to glyphosate, toxicity and perturbed physiological functions in non-target organisms. Although glyphosate formulations are widely used for weed and alien plant management, their ecotoxicological information remain scanty. Using the 96-hour Frog Embryo Teratogenesis Assay-Xenopus protocol, embryotoxicity and teratogenicity of three glyphosate-based formulations were assessed. Embryos of Xenopus laevis were exposed to Roundup, Kilo Max and Enviro Glyphosate at concentration of 0.3-1.3, 130-280 and 320-560 mg acid equivalent (a.e.)/L respectively. The results showed Roundup to be more toxic than the other formulations with a 96-hour LC50 of 1.05 mg a.e/L. compared with 207 mg a.e./L, and 466 mg a.e./L for Kilo Max and Enviro Glyphosate respectively. Although, both Roundup and Kilo Max formulations show inhibition on growth of the embryo-larva (P ˂ .05), the minimum concentration inhibiting growth ratios of the three formulations was >0.30 baseline, indicating no significant growth inhibiting effect in the formulations. For teratogenicity, Roundup and Enviro Glyphosate formulations exhibited increasing teratogenic traces, with the teratogenic index at 1.7 and 1.6 respectively. Kilo Max formulation shows low teratogenicity with the teratogenic index at 1.4. Characteristic malformation induced by these formulations included generalized edema, cardiac and abdominal edema, improper gut formation and axial malformations. This study confirms that these formulations could be a potential physiological and ecological health disruptor, particularly concerning teratogenicity and growth disruption. Further studies to characterize the contributions of their surfactants will be invaluable.
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Affiliation(s)
- O Oluwaseun Babalola
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - J Christoff Truter
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Johannes H van Wyk
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
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Pownall ME, Saha MS. Histological Observation of Teratogenic Phenotypes Induced in Frog Embryo Assays. Methods Mol Biol 2019; 1797:309-323. [PMID: 29896700 DOI: 10.1007/978-1-4939-7883-0_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Amphibian embryos have long served as an ideal model for teratogenicity testing. While whole-mount embryo observations can be utilized, histological observation of teratogenic phenotypes provides a wealth of additional information that can lead to mechanistic insights. In this chapter, detailed protocols for two methods of sectioning embryos as well as a guide for histological analysis is provided.
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Affiliation(s)
- Mark E Pownall
- Department of Biology, College of William and Mary, Williamsburg, VA, USA
| | - Margaret S Saha
- Department of Biology, College of William and Mary, Williamsburg, VA, USA.
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10
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Bonfanti P, Saibene M, Bacchetta R, Mantecca P, Colombo A. A glyphosate micro-emulsion formulation displays teratogenicity in Xenopus laevis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 195:103-113. [PMID: 29306033 DOI: 10.1016/j.aquatox.2017.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/03/2017] [Accepted: 12/18/2017] [Indexed: 06/07/2023]
Abstract
Glyphosate is the active ingredient in broad-spectrum herbicide formulations used in agriculture, domestic area and aquatic weed control worldwide. Its market is growing steadily concurrently with the cultivation of glyphosate-tolerant transgenic crops and emergence of weeds less sensitive to glyphosate. Ephemeral and lentic waters near to agricultural lands, representing favorite habitats for amphibian reproduction and early life-stage development, may thus be contaminated by glyphosate based herbicides (GBHs) residues. Previous studies on larval anuran species highlighted increased mortality and growth effects after exposure to different GBHs in comparison to glyphosate itself, mainly because of the surfactants such as polyethoxylated tallow amine present in the formulations. Nevertheless, these conclusions are not completely fulfilled when the early development, characterized by primary organogenesis events, is considered. In this study, we compare the embryotoxicity of Roundup® Power 2.0, a new GBH formulation currently authorized in Italy, with that of technical grade glyphosate using the Frog Embryo Teratogenesis Assay-Xenopus (FETAX). Our results evidenced that glyphosate was not embryolethal and only at the highest concentration (50 mg a.e./L) caused edemas. Conversely, Roundup® Power 2.0 exhibited a 96 h LC50 of 24.78 mg a.e./L and a 96 h EC50 of 7.8 mg a.e./L. A Teratogenic Index of 3.4 was derived, pointing out the high teratogenic potential of the Roundup® Power 2.0. Specific concentration-dependent abnormal phenotypes, such as craniofacial alterations, microphthalmia, narrow eyes and forebrain regionalization defects were evidenced by gross malformation screening and histopathological analysis. These phenotypes are coherent with those evidenced in Xenopus laevis embryos injected with glyphosate, allowing us to hypothesize that the teratogenicity observed for Roundup® Power 2.0 may be related to the improved efficacy in delivering glyphosate to cells, guaranteed by the specific surfactant formulation. In conclusion, the differences in GBH formulations should be carefully considered by the authorities, since sub-lethal and/or long-term effects (e.g. teratogenicity) can be significantly modulated by the active ingredient salt type and concentration of the adjuvants. Finally, the mechanistic toxicity of glyphosate and GBHs are worthy of further research.
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Affiliation(s)
- Patrizia Bonfanti
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, 1, Piazza della Scienza, 20126 Milan, Italy.
| | - M Saibene
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, 1, Piazza della Scienza, 20126 Milan, Italy
| | - R Bacchetta
- Department of Environmental Science and Policy, University of Milan, 26, Via Celoria, 20133 Milan, Italy
| | - P Mantecca
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, 1, Piazza della Scienza, 20126 Milan, Italy
| | - A Colombo
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, 1, Piazza della Scienza, 20126 Milan, Italy
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Abstract
Developmental toxicology is a constantly evolving research field which needs to attend to a complex underlying regulatory network. Before entering the market new substances have to be tested for toxic effects on reproduction and development in order to ensure human health and environmental safety. Traditional in vivo mammalian models represent more adequately the intricacy of human development and provide an assessment of the interaction of chemicals on the reproductive system. However, in the last years, the main goal is to reduce the use of vertebrate animals, using those only as last resort. Consequently, the interest in the development and validation of a battery of alternative tests able to cover the various aspects of the reproductive cycle has increased. Reproductive toxicity is probably the most difficult endpoint to be replaced by alternative assays, since it should provide information on mechanisms interactions essential for female and male fertility, and also knowledge on the development of a new human being during its prenatal life. This complexity explains the slow progress in implementing alternatives for reproductive toxicity safety assessments. Alternative test methods may be based on in vitro systems and non-mammalian animal models. Many biological processes have been successfully implemented using in vitro models, opening the possibility to study the interference of teratogenic compounds using these models. Their validation and implementation have lagged behind, in part because of difficulties in establishing their predictability. Nevertheless, the advance toward the process of validation is crucial for a strategy aiming to replace and reduce the use of living animals. Based on the present state of the art, it is not probable that such testing strategies will completely replace the need to assess reproductive toxicity in vivo in the near future, but they contribute to reduce the animal testing and provide important information. In this chapter the approved guidelines for standard methods and alternative methods according to their regulatory and scientific status are enumerated and described.
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Zhu J, Hu L, Li L, Huang X, Shi H. Comparison of phenotypic and global gene expression changes in Xenopus tropicalis embryos induced by agonists of RAR and RXR. Toxicol Appl Pharmacol 2017; 330:40-47. [DOI: 10.1016/j.taap.2017.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 06/24/2017] [Accepted: 07/05/2017] [Indexed: 12/31/2022]
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13
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Colombo A, Saibene M, Moschini E, Bonfanti P, Collini M, Kasemets K, Mantecca P. Teratogenic hazard of BPEI-coated silver nanoparticles to Xenopus laevis. Nanotoxicology 2017; 11:405-418. [DOI: 10.1080/17435390.2017.1309703] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Anita Colombo
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milan, Italy
| | - Melissa Saibene
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milan, Italy
| | - Elisa Moschini
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milan, Italy
- Environmental Research and Innovation (ERIN) Department, Luxembourg, Institute of Science and Technology (LIST), Esch-sur-Alzette, Luxembourg
| | - Patrizia Bonfanti
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milan, Italy
| | | | - Kaja Kasemets
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milan, Italy
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Paride Mantecca
- Department of Earth and Environmental Sciences, Research Centre POLARIS, University of Milano-Bicocca, Milan, Italy
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Zhu J, Janesick A, Wu L, Hu L, Tang W, Blumberg B, Shi H. The unexpected teratogenicity of RXR antagonist UVI3003 via activation of PPARγ in Xenopus tropicalis. Toxicol Appl Pharmacol 2017; 314:91-97. [PMID: 27894914 PMCID: PMC5183475 DOI: 10.1016/j.taap.2016.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/31/2016] [Accepted: 11/23/2016] [Indexed: 01/28/2023]
Abstract
The RXR agonist (triphenyltin, TPT) and the RXR antagonist (UVI3003) both show teratogenicity and, unexpectedly, induce similar malformations in Xenopus tropicalis embryos. In the present study, we exposed X. tropicalis embryos to UVI3003 in seven specific developmental windows and identified changes in gene expression. We further measured the ability of UVI3003 to activate Xenopus RXRα (xRXRα) and PPARγ (xPPARγ) in vitro and in vivo. We found that UVI3003 activated xPPARγ either in Cos7 cells (in vitro) or Xenopus embryos (in vivo). UVI3003 did not significantly activate human or mouse PPARγ in vitro; therefore, the activation of Xenopus PPARγ by UVI3003 is novel. The ability of UVI3003 to activate xPPARγ explains why UVI3003 and TPT yield similar phenotypes in Xenopus embryos. Our results indicate that activating PPARγ leads to teratogenic effects in Xenopus embryos. More generally, we infer that chemicals known to specifically modulate mammalian nuclear hormone receptors cannot be assumed to have the same activity in non-mammalian species, such as Xenopus. Rather they must be tested for activity and specificity on receptors of the species in question to avoid making inappropriate conclusions.
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Affiliation(s)
- Jingmin Zhu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Amanda Janesick
- Department of Developmental and Cell Biology, University of California, Irvine, California 92697-2300, USA
| | - Lijiao Wu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Lingling Hu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Weiyi Tang
- Department of Developmental and Cell Biology, University of California, Irvine, California 92697-2300, USA
| | - Bruce Blumberg
- Department of Developmental and Cell Biology, University of California, Irvine, California 92697-2300, USA
| | - Huahong Shi
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
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15
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Hu L, Zhu J, Rotchell JM, Wu L, Gao J, Shi H. Use of the enhanced frog embryo teratogenesis assay-Xenopus (FETAX) to determine chemically-induced phenotypic effects. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 508:258-265. [PMID: 25481254 DOI: 10.1016/j.scitotenv.2014.11.086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/07/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
The frog embryo teratogenesis assay-Xenopus (FETAX) is an established method for the evaluation of the developmental toxicities of chemicals. To develop an enhanced FETAX that is appropriate for common environmental contaminants, we exposed Xenopus tropicalis embryos to eight compounds, including tributyltin, triphenyltin, CdCl2, pyraclostrobin, picoxystrobin, coumoxystrobin, all-trans-retinoic acid and 9-cis-retinoic acid. Multiple malformations were induced in embryos particularly following exposure to tributyltin, triphenyltin and pyraclostrobin at environmentally relevant concentrations. Based on the range of observed malformations, we proposed a phenotypic assessment method with 20 phenotypes and a 0-5 scoring system. This derived index exhibited concentration-dependent relationships for all of the chemicals tested. Furthermore, the phenotype profiles were characteristic of the different tested chemicals. Our results indicate that malformation phenotypes can be quantitatively integrated with the primary endpoints in conventional FETAX assessments to allow for increased sensitivity and measurement of quantitative effects and to provide indicative mechanistic information for each tested chemical.
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Affiliation(s)
- Lingling Hu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Jingmin Zhu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Jeanette M Rotchell
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China; School of Biological, Biomedical & Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom
| | - Lijiao Wu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Jinjuan Gao
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Huahong Shi
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
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16
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Nuclear and spectrochemical techniques in developmental metal toxicology research. Whole-body elemental composition of Xenopus laevis larvae. J Radioanal Nucl Chem 2014. [DOI: 10.1007/s10967-014-3792-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Zhu F, Skommer J, Huang Y, Akagi J, Adams D, Levin M, Hall CJ, Crosier PS, Wlodkowic D. Fishing on chips: up-and-coming technological advances in analysis of zebrafish and Xenopus embryos. Cytometry A 2014; 85:921-32. [PMID: 25287981 PMCID: PMC10472801 DOI: 10.1002/cyto.a.22571] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/31/2014] [Accepted: 08/29/2014] [Indexed: 12/29/2022]
Abstract
Biotests performed on small vertebrate model organisms provide significant investigative advantages as compared with bioassays that employ cell lines, isolated primary cells, or tissue samples. The main advantage offered by whole-organism approaches is that the effects under study occur in the context of intact physiological milieu, with all its intercellular and multisystem interactions. The gap between the high-throughput cell-based in vitro assays and low-throughput, disproportionally expensive and ethically controversial mammal in vivo tests can be closed by small model organisms such as zebrafish or Xenopus. The optical transparency of their tissues, the ease of genetic manipulation and straightforward husbandry, explain the growing popularity of these model organisms. Nevertheless, despite the potential for miniaturization, automation and subsequent increase in throughput of experimental setups, the manipulation, dispensing and analysis of living fish and frog embryos remain labor-intensive. Recently, a new generation of miniaturized chip-based devices have been developed for zebrafish and Xenopus embryo on-chip culture and experimentation. In this work, we review the critical developments in the field of Lab-on-a-Chip devices designed to alleviate the limits of traditional platforms for studies on zebrafish and clawed frog embryo and larvae. © 2014 International Society for Advancement of Cytometry.
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Affiliation(s)
- Feng Zhu
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - Joanna Skommer
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - Yushi Huang
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - Jin Akagi
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - Dany Adams
- Department of Biology and Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts
| | - Michael Levin
- Department of Biology and Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts
| | - Chris J. Hall
- Department of Molecular Medicine and Pathology, University of Auckland, 1142, New Zealand
| | - Philip S. Crosier
- Department of Molecular Medicine and Pathology, University of Auckland, 1142, New Zealand
| | - Donald Wlodkowic
- School of Applied Sciences, RMIT University, Melbourne, Australia
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Louisse J, Verwei M, Woutersen RA, Blaauboer BJ, Rietjens IMCM. Towardin vitrobiomarkers for developmental toxicity and their extrapolation to thein vivosituation. Expert Opin Drug Metab Toxicol 2011; 8:11-27. [DOI: 10.1517/17425255.2012.639762] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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19
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Orton F, Routledge E. Agricultural intensity in ovo affects growth, metamorphic development and sexual differentiation in the common toad (Bufo bufo). ECOTOXICOLOGY (LONDON, ENGLAND) 2011; 20:901-911. [PMID: 21448622 DOI: 10.1007/s10646-011-0658-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/17/2011] [Indexed: 05/30/2023]
Abstract
Pollution was cited by the Global Amphibian Assessment to be the second most important cause of amphibian decline worldwide, however, the effects of the agricultural environment on amphibians are not well understood. In this study, spawn from Bufo bufo was taken from four sites in England and Wales with varying intensities of arable agriculture. Spawn was either placed in tanks containing aged tap water (ex-situ, five replicates) or in cages at the native site (caged, five replicates). Hatching success, abnormal tadpoles, and forelimb emergence were recorded during the larval stage. Individuals were also sampled at five time points (TP) during development (5-, 7-, 9-, 12-, 15-weeks post-hatch) and analysed for morphological parameters. The thyroids (TP2) and the gonads (TP3,4,5) were also analysed histologically. With the exception of the thyroid histopathology, all analysed endpoints were significantly different between ex-situ individuals reared under identical conditions from the different sites. In addition, intensity of arable agriculture had a negative effect on growth and development. At one site, despite distinct rearing conditions, a high level of intersex (up to 42%) and similar sex ratios were observed in both ex-situ and caged individuals. Taken together, these data suggest that maternal exposure and/or events in ovo had a much larger effect on growth, metamorphic development, and sexual differentiation in B. bufo than the ambient environment. This could have important implications for traditional exposure scenarios that typically begin at the larval stage. Intersex is reported for the first time in European amphibians in situ, highlighting the potential use of distinct populations of amphibians in fundamental research into the aetiology of specific developmental effects in wild amphibians.
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Affiliation(s)
- Frances Orton
- Institute for the Environment, Brunel University, Kingston Lane, Uxbridge, UB8 3PH, UK.
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Wlodkowic D, Khoshmanesh K, Akagi J, Williams DE, Cooper JM. Wormometry-on-a-chip: Innovative technologies for in situ analysis of small multicellular organisms. Cytometry A 2011; 79:799-813. [PMID: 21548078 DOI: 10.1002/cyto.a.21070] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 03/09/2011] [Accepted: 03/30/2011] [Indexed: 12/12/2022]
Abstract
Small multicellular organisms such as nematodes, fruit flies, clawed frogs, and zebrafish are emerging models for an increasing number of biomedical and environmental studies. They offer substantial advantages over cell lines and isolated tissues, providing analysis under normal physiological milieu of the whole organism. Many bioassays performed on these alternative animal models mirror with a high level of accuracy those performed on inherently low-throughput, costly, and ethically controversial mammalian models of human disease. Analysis of small model organisms in a high-throughput and high-content manner is, however, still a challenging task not easily susceptible to laboratory automation. In this context, recent advances in photonics, electronics, as well as material sciences have facilitated the emergence of miniaturized bioanalytical systems collectively known as Lab-on-a-Chip (LOC). These technologies combine micro- and nanoscale sciences, allowing the application of laminar fluid flow at ultralow volumes in spatially confined chip-based circuitry. LOC technologies are particularly advantageous for the development of a wide array of automated functionalities. The present work outlines the development of innovative miniaturized chip-based devices for the in situ analysis of small model organisms. We also introduce a new term "wormometry" to collectively distinguish these up-and-coming chip-based technologies that go far beyond the conventional meaning of the term "cytometry."
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Affiliation(s)
- Donald Wlodkowic
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Auckland, Auckland, 1142, New Zealand.
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21
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Adler S, Basketter D, Creton S, Pelkonen O, van Benthem J, Zuang V, Andersen KE, Angers-Loustau A, Aptula A, Bal-Price A, Benfenati E, Bernauer U, Bessems J, Bois FY, Boobis A, Brandon E, Bremer S, Broschard T, Casati S, Coecke S, Corvi R, Cronin M, Daston G, Dekant W, Felter S, Grignard E, Gundert-Remy U, Heinonen T, Kimber I, Kleinjans J, Komulainen H, Kreiling R, Kreysa J, Leite SB, Loizou G, Maxwell G, Mazzatorta P, Munn S, Pfuhler S, Phrakonkham P, Piersma A, Poth A, Prieto P, Repetto G, Rogiers V, Schoeters G, Schwarz M, Serafimova R, Tähti H, Testai E, van Delft J, van Loveren H, Vinken M, Worth A, Zaldivar JM. Alternative (non-animal) methods for cosmetics testing: current status and future prospects-2010. Arch Toxicol 2011; 85:367-485. [PMID: 21533817 DOI: 10.1007/s00204-011-0693-2] [Citation(s) in RCA: 358] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/03/2011] [Indexed: 01/09/2023]
Abstract
The 7th amendment to the EU Cosmetics Directive prohibits to put animal-tested cosmetics on the market in Europe after 2013. In that context, the European Commission invited stakeholder bodies (industry, non-governmental organisations, EU Member States, and the Commission's Scientific Committee on Consumer Safety) to identify scientific experts in five toxicological areas, i.e. toxicokinetics, repeated dose toxicity, carcinogenicity, skin sensitisation, and reproductive toxicity for which the Directive foresees that the 2013 deadline could be further extended in case alternative and validated methods would not be available in time. The selected experts were asked to analyse the status and prospects of alternative methods and to provide a scientifically sound estimate of the time necessary to achieve full replacement of animal testing. In summary, the experts confirmed that it will take at least another 7-9 years for the replacement of the current in vivo animal tests used for the safety assessment of cosmetic ingredients for skin sensitisation. However, the experts were also of the opinion that alternative methods may be able to give hazard information, i.e. to differentiate between sensitisers and non-sensitisers, ahead of 2017. This would, however, not provide the complete picture of what is a safe exposure because the relative potency of a sensitiser would not be known. For toxicokinetics, the timeframe was 5-7 years to develop the models still lacking to predict lung absorption and renal/biliary excretion, and even longer to integrate the methods to fully replace the animal toxicokinetic models. For the systemic toxicological endpoints of repeated dose toxicity, carcinogenicity and reproductive toxicity, the time horizon for full replacement could not be estimated.
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Affiliation(s)
- Sarah Adler
- Centre for Documentation and Evaluation of Alternatives to Animal Experiments (ZEBET), Federal Institute for Risk Assessment (BfR), Berlin, Germany
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Hermsen SA, van den Brandhof EJ, van der Ven LT, Piersma AH. Relative embryotoxicity of two classes of chemicals in a modified zebrafish embryotoxicity test and comparison with their in vivo potencies. Toxicol In Vitro 2011; 25:745-53. [DOI: 10.1016/j.tiv.2011.01.005] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 01/05/2011] [Accepted: 01/09/2011] [Indexed: 10/18/2022]
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Rayburn JR, Friedman M. L-cysteine, N-acetyl-L-cysteine, and glutathione protect Xenopus laevis embryos against acrylamide-induced malformations and mortality in the frog embryo teratogenesis assay. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:11172-11178. [PMID: 20873821 DOI: 10.1021/jf1023998] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Dietary acrylamide is largely derived from heat-induced reactions between the amino group of the free amino acid asparagine and carbonyl groups of glucose and fructose during heat processing (baking, frying) of plant-derived foods such as potato fries and cereals. After consumption, acrylamide is absorbed into the circulation and is then distributed to various organs, where it can react with DNA, neurons, hemoglobin, and essential enzymes. In the present study, we explored the potential of L-cysteine (CySH), N-acetyl-L-cysteine (NAC), reduced glutathione (GSH), and the amino acid glycine (Gly) to protect frog embryos against acrylamide-induced developmental toxicity in the frog embryo teratogenesis assay - Xenopus (FETAX). To test the antiteratogenic potential, based on concentration-response study ranging from 0.07 to 4.22 mM acrylamide in FETAX solution (pH 8.1), we selected concentrations of acrylamide that induced 100% malformations and mortality. At the end of 96 h, we counted survivors and malformed embryos and measured embryo length. The data show that CySH, NAC, and GSH protected the embryos against acrylamide induced malformations and mortality to different degrees. CySH and GSH protected the embryos against both malformations and mortality, whereas NAC protected only against mortality. Gly had no protective effect. Possible mechanisms of the protective effects and the dietary significance of the results of this and related studies for food safety and human health are discussed.
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Affiliation(s)
- James R Rayburn
- Biology Department, Jacksonville State University, Jacksonville, Alabama 36265
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Bosisio S, Fortaner S, Bellinetto S, Farina M, Del Torchio R, Prati M, Gornati R, Bernardini G, Sabbioni E. Developmental toxicity, uptake and distribution of sodium chromate assayed by frog embryo teratogenesis assay-Xenopus(FETAX). THE SCIENCE OF THE TOTAL ENVIRONMENT 2009; 407:5039-5045. [PMID: 19540565 DOI: 10.1016/j.scitotenv.2009.05.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 03/16/2009] [Accepted: 05/28/2009] [Indexed: 05/27/2023]
Abstract
The embryotoxicity and teratogenicity of Cr(VI) on the survival and morphology of the anuran Xenopus laevis have been assessed by frog embryo teratogenesis assay-Xenopus (FETAX). The lethal median (LC(50)) and teratogenic median (TC(50)) concentration values of Cr(VI) were 890 microM and 260 microM, respectively. The calculated teratogenic index (TI) value was 3.42, suggesting that hexavalent chromium has a teratogenic potential. Malformations of embryos included lifting of the body, coiling of the tail and body oedema. Furthermore, the chromium salt caused significant growth retardation at 25 microM exposure concentrations. The use of radiolabelled (51)Cr(VI) allowed the determination of the time course uptake of Cr in Xenopus exposed to concentrations ranging from 0.025 to 500 microM. The evaluation of its distribution into the body (head-abdomen-tail) was evaluated at different exposure times. Chromium is taken up at 24 h by Xenopus embryos for all concentrations tested. At 48 h post fertilization (stage of larva) the amount of Cr accumulated by the two-day-old larva ranged from 0.42 to 580 pg mg(-1) wet weight at 0.025 and 500 microM respectively. These amounts were lower than those at 24 h (2.77 to 11016 pg mg(-1) wet weight embryo) reaching values of the same order of magnitude at 120 h (five-days-old larva). Since at 48 h Xenopus development leads to a swimming embryo, the observed uptake at 24 h could be the result of the binding of Cr to jelly coat compounds surrounding the embryo body as confirmed by gel filtration experiments on (51)Cr-jelly coat. The interaction of Cr with jelly coat is in agreement with the role of jelly coat in protecting the embryo against pathogen and chemical toxins to ensure fertilization. This work further supports the hypothesis that Cr contamination of surface waters could contribute to explain the reported worldwide depletion of frog population.
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Gutleb AC, Mossink L, Schriks M, van den Berg HJH, Murk AJ. Delayed effects of environmentally relevant concentrations of 3,3',4,4'-tetrachlorobiphenyl (PCB-77) and non-polar sediment extracts detected in the prolonged-FETAX. THE SCIENCE OF THE TOTAL ENVIRONMENT 2007; 381:307-15. [PMID: 17451789 DOI: 10.1016/j.scitotenv.2007.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 02/02/2007] [Accepted: 03/01/2007] [Indexed: 05/15/2023]
Abstract
In the prolonged-FETAX (prolonged-Frog Embryo Teratogenic Assay-Xenopus) tadpoles are allowed to develop until metamorphosis after an initial 4 day early life-stage exposure (FETAX). PCB 77 (3,4,3',4'-tetrachlorobiphenyl) and sediment extracts were used in the presented experiments. Concentrations of PCB 77 (0.03 nM=8.55 ng/L; 3 nM=855 ng/L; 300 nM=85.5 microg/L, 30,000 nM=8.55 mg/L) were derived on the basis of dioxin-like toxic equivalency concentrations known to be present in pore-water. The results were compared to those obtained with the standard FETAX. In the prolonged-FETAX the percentage of animals passing metamorphosis within 115 days was significantly decreased in the groups exposed to 300 or 30,000 nM PCB 77. Significantly increased percentages of tadpoles were halted in thyroid hormone dependent early metamorphic NF stages <or=55 (3 nM PCB 77) and metamorphic stages 56-60 tadpoles (300 nM PCB 77 and 30,000 nM PCB 77). Non-polar sediment extracts from two contaminated Dutch sites significantly decreased, and one significantly increased the percentage of animals that passed metamorphosis. These results were in accordance with earlier in vitro results in a thyroid hormone dependent assay and strongly suggest the presence of thyroid hormone disrupting compounds in the aquatic environment. In the classical FETAX neither PCB 77 nor non-polar sediment extracts induced any effects. The results of the present study indicate that the prolonged-FETAX is an important in vivo tool in addition to the in vitro T-screen to assess long-term effects of early life-stage exposure to environmentally relevant concentrations of (mixtures of) compounds and that affect thyroid hormone dependent physiology.
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Affiliation(s)
- Arno C Gutleb
- Toxicology Section, Wageningen University, Tuinlaan 5 NL-6703 HE Wageningen, The Netherlands.
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Abstract
Fluoride was first associated with fetal malformation shortly after water fluoridation was initiated in the 1940s. Since many chemicals can interact directly with the embryo to cause malformation, the effects of fluoride on embryonic and fetal development were investigated. The effects of sodium fluoride on the development of frog embryos were studied under conditions described by the Frog Embryo Teratogenesis Assay-Xenopus (FETAX), a screening assay for teratogens. The most prominent malformations caused by sodium fluoride are reduction in the head-tail lengths and dysfunction of the neuromuscular system of the tadpoles. The values for LC50, EC50, and minimal concentration to inhibit growth (MCIG) of sodium fluoride met the limits established for a teratogen in frog embryos, showing that sodium fluoride is a direct acting teratogen on developing embryos. Since FETAX has a high degree of success in identifying mammalian teratogens, the observed teratogenic action of sodium fluoride on frog embryos would indicate a strong possibility that sodium fluoride may also act directly on developing mammalian fetuses to cause malformation.
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Affiliation(s)
- E H Goh
- Associate Professor of Pharmacology and Toxicology, Indiana University School of Medicine, Medical Sciences Program, Jordan Hall 009A, Bloomington, IN 47405, USA.
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