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Marty MS, Borgert C, Coady K, Green R, Levine SL, Mihaich E, Ortego L, Wheeler JR, Yi KD, Zorrilla LM. Distinguishing between endocrine disruption and non-specific effects on endocrine systems. Regul Toxicol Pharmacol 2018; 99:142-158. [PMID: 30217484 DOI: 10.1016/j.yrtph.2018.09.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/04/2018] [Indexed: 10/28/2022]
Abstract
The endocrine system is responsible for growth, development, maintaining homeostasis and for the control of many physiological processes. Due to the integral nature of its signaling pathways, it can be difficult to distinguish endocrine-mediated adverse effects from transient fluctuations, adaptive/compensatory responses, or adverse effects on the endocrine system that are caused by mechanisms outside the endocrine system. This is particularly true in toxicological studies that require generation of effects through the use of Maximum Tolerated Doses (or Concentrations). Endocrine-mediated adverse effects are those that occur as a consequence of the interaction of a chemical with a specific molecular component of the endocrine system, for example, a hormone receptor. Non-endocrine-mediated adverse effects on the endocrine system are those that occur by other mechanisms. For example, systemic toxicity, which perturbs homeostasis and affects the general well-being of an organism, can affect endocrine signaling. Some organs/tissues can be affected by both endocrine and non-endocrine signals, which must be distinguished. This paper examines in vitro and in vivo endocrine endpoints that can be altered by non-endocrine processes. It recommends an evaluation of these issues in the assessment of effects for the determination of endocrine disrupting properties of chemicals. This underscores the importance of using a formal weight of evidence (WoE) process to evaluate potential endocrine activity.
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Affiliation(s)
- M Sue Marty
- The Dow Chemical Company, Toxicology & Environmental Research and Consulting, 1803 Building, Midland, MI, 48674, USA.
| | - Chris Borgert
- Applied Pharmacology and Toxicology, Inc., C.E.H.T. Dept. Physiological Sciences, University of FL College of Veterinary Medicine, 2250 NW 24th Avenue, Gainesville, FL, 32605, USA.
| | - Katie Coady
- The Dow Chemical Company, Toxicology & Environmental Research and Consulting, 1803 Building, Midland, MI, 48674, USA.
| | - Richard Green
- Dow AgroSciences, 3b Park Square, Milton Park, Abingdon, Oxfordshire, OX14 4RN, United Kingdom.
| | - Steven L Levine
- Monsanto Company, Global Regulatory Science, 700 Chesterfield Parkway W, Chesterfield, MO, 63017, USA.
| | - Ellen Mihaich
- Environmental and Regulatory Resources, LLC, 6807 Lipscomb Drive, Durham, NC, 27712, USA.
| | - Lisa Ortego
- Bayer CropScience, 2 TW Alexander Dr, Research Triangle Park, NC, 27709, USA.
| | - James R Wheeler
- Dow AgroSciences, 3b Park Square, Milton Park, Abingdon, Oxfordshire, OX14 4RN, United Kingdom.
| | - Kun Don Yi
- Syngenta Crop Protection, LLC, 410 S Wing Rd, Greensboro, NC, 27409, USA.
| | - Leah M Zorrilla
- Bayer CropScience, 2 TW Alexander Dr, Research Triangle Park, NC, 27709, USA.
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2
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Martins D, Monteiro MS, Soares AMVM, Quintaneiro C. Effects of 4-MBC and triclosan in embryos of the frog Pelophylax perezi. CHEMOSPHERE 2017; 178:325-332. [PMID: 28334672 DOI: 10.1016/j.chemosphere.2017.03.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 06/06/2023]
Abstract
The widespread and increasing use of personal care products (PCPs) have led to environmental contamination by substances included in these products. These substances have been detected in aquatic compartments and shown to cause adverse effects on non-target aquatic organisms. In this work toxicity of the antimicrobial triclosan (TCS) and of the UV-filter 3-(4-methylbenzylidene) camphor (4-MBC) was assessed in the embryos of Perez' frog Pelophylax perezi. Lethal and sub-lethal parameters were evaluated in embryos in Gosner stage 8-9 exposed to 0.00013-1.3 mg/l of 4-MBC and 0.25-2.50 mg/l of TCS during 144 h. Survival, malformations, length and hatching were evaluated as apical endpoints. Biomarkers of neurotransmission, oxidative stress, energy metabolism and estrogenicity were determined at the biochemical level through the activities of cholinesterase (ChE), catalase (CAT), glutathione S-transferase (GST), lactate dehydrogenase (LDH) and levels of lipid peroxidation (LPO) and vitellogenin (Vtg). Embryo exposure to 4-MBC led to few developmental malformations (up to 3%) and a GST induction at 0.013 mg/l. Triclosan exposure reduced survival, delayed hatching (at 72 h) and development and induced malformations. In addiction ChE was inhibited in the highest concentrations tested and GST and LDH were induced at 0.79 mg/l, the LOEC registered for TCS in Perez' frogs. Overall, our study showed that TCS might exert adverse effects on P. perezi early life stages, but only at four orders of magnitude above the concentrations found in environment. Furthermore, our results highlight the need to assess PCPs toxicity at different levels of biological organization.
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Affiliation(s)
- Diana Martins
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Marta S Monteiro
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Amadeu M V M Soares
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Carla Quintaneiro
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
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3
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Prenatal exposure to environmental factors and congenital limb defects. ACTA ACUST UNITED AC 2016; 108:243-273. [DOI: 10.1002/bdrc.21140] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 09/29/2016] [Indexed: 12/26/2022]
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4
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Liu LS, Zhao LY, Wang SH, Jiang JP. Research proceedings on amphibian model organisms. DONG WU XUE YAN JIU = ZOOLOGICAL RESEARCH 2016; 37:237-45. [PMID: 27469255 PMCID: PMC4980064 DOI: 10.13918/j.issn.2095-8137.2016.4.237] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 06/10/2016] [Indexed: 12/26/2022]
Abstract
Model organisms have long been important in biology and medicine due to their specific characteristics. Amphibians, especially Xenopus, play key roles in answering fundamental questions on developmental biology, regeneration, genetics, and toxicology due to their large and abundant eggs, as well as their versatile embryos, which can be readily manipulated and developed in vivo. Furthermore, amphibians have also proven to be of considerable benefit in human disease research due to their conserved cellular developmental and genomic organization. This review gives a brief introduction on the progress and limitations of these animal models in biology and human disease research, and discusses the potential and challenge of Microhyla fissipes as a new model organism.
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Affiliation(s)
- Lu-Sha Liu
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Lan-Ying Zhao
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China;University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shou-Hong Wang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China;University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian-Ping Jiang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
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5
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Mathieu-Denoncourt J, Wallace SJ, de Solla SR, Langlois VS. Plasticizer endocrine disruption: Highlighting developmental and reproductive effects in mammals and non-mammalian aquatic species. Gen Comp Endocrinol 2015; 219:74-88. [PMID: 25448254 DOI: 10.1016/j.ygcen.2014.11.003] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/30/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
Abstract
Due to their versatility, robustness, and low production costs, plastics are used in a wide variety of applications. Plasticizers are mixed with polymers to increase flexibility of plastics. However, plasticizers are not covalently bound to plastics, and thus leach from products into the environment. Several studies have reported that two common plasticizers, bisphenol A (BPA) and phthalates, induce adverse health effects in vertebrates; however few studies have addressed their toxicity to non-mammalian species. The aim of this review is to compare the effects of plasticizers in animals, with a focus on aquatic species. In summary, we identified three main chains of events that occur in animals exposed to BPA and phthalates. Firstly, plasticizers affect development by altering both the thyroid hormone and growth hormone axes. Secondly, these chemicals interfere with reproduction by decreasing cholesterol transport through the mitochondrial membrane, leading to reduced steroidogenesis. Lastly, exposure to plasticizers leads to the activation of peroxisome proliferator-activated receptors, the increase of fatty acid oxidation, and the reduction in the ability to cope with the augmented oxidative stress leading to reproductive organ malformations, reproductive defects, and decreased fertility.
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Affiliation(s)
- Justine Mathieu-Denoncourt
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Sarah J Wallace
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Shane R de Solla
- Wildlife and Landscape Science Directorate, Environment Canada, Burlington, ON L7R 4A6, Canada
| | - Valerie S Langlois
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada.
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6
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Mathieu-Denoncourt J, de Solla SR, Langlois VS. Chronic exposures to monomethyl phthalate in Western clawed frogs. Gen Comp Endocrinol 2015; 219:53-63. [PMID: 25662408 DOI: 10.1016/j.ygcen.2015.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 12/11/2014] [Accepted: 01/23/2015] [Indexed: 01/24/2023]
Abstract
Polymer flexibility and elasticity is enhanced by plasticizers. However, plasticizers are often not covalently bound to plastics and thus can leach from products into the environment. Much research effort has focused on their effects in mammalian species, but data on aquatic species are scarce. In this study, Western clawed frog (Silurana tropicalis) embryos were exposed to 1.3, 12.3, and 128.7mg/L monomethyl phthalate (MMP) until the juvenile stage (11weeks) and to 1.3mg/L MMP until the adult stage (51weeks). MMP decreased survival, hastened metamorphosis, and biased the sex ratio toward males (2M:1F) at the juvenile stage without altering the expression of a subset of thyroid hormone-, sex steroid-, cellular stress- or transcription regulation-related genes in the juvenile frog livers. At the adult stage, exposure to MMP did not have significant adverse health effects, except that females had larger interocular distance and the expression of the heat shock protein 70 was decreased by 60% in the adult liver. In conclusion, this study shows that MMP is unlikely to threaten amphibian populations as only concentrations four orders of magnitude higher than the reported environmental concentrations altered the animal physiology. This is the first complete investigation of the effects of phthalates in a frog species, encompassing the entire life cycle of the organisms.
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Affiliation(s)
- Justine Mathieu-Denoncourt
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Shane R de Solla
- Wildlife and Landscape Science Directorate, Environment Canada, Burlington, ON L7S 1A1, Canada
| | - Valerie S Langlois
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada.
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7
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Pratt KG, Khakhalin AS. Modeling human neurodevelopmental disorders in the Xenopus tadpole: from mechanisms to therapeutic targets. Dis Model Mech 2013; 6:1057-65. [PMID: 23929939 PMCID: PMC3759326 DOI: 10.1242/dmm.012138] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Xenopus tadpole model offers many advantages for studying the molecular, cellular and network mechanisms underlying neurodevelopmental disorders. Essentially every stage of normal neural circuit development, from axon outgrowth and guidance to activity-dependent homeostasis and refinement, has been studied in the frog tadpole, making it an ideal model to determine what happens when any of these stages are compromised. Recently, the tadpole model has been used to explore the mechanisms of epilepsy and autism, and there is mounting evidence to suggest that diseases of the nervous system involve deficits in the most fundamental aspects of nervous system function and development. In this Review, we provide an update on how tadpole models are being used to study three distinct types of neurodevelopmental disorders: diseases caused by exposure to environmental toxicants, epilepsy and seizure disorders, and autism.
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Affiliation(s)
- Kara G. Pratt
- University of Wyoming, 1000 E University Avenue, Laramie, WY 82071, USA
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8
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Spawn A, Aizenman CD. Abnormal visual processing and increased seizure susceptibility result from developmental exposure to the biocide methylisothiazolinone. Neuroscience 2012; 205:194-204. [PMID: 22245758 DOI: 10.1016/j.neuroscience.2011.12.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 12/23/2011] [Accepted: 12/28/2011] [Indexed: 12/21/2022]
Abstract
Methylisothiazolinone (MIT) is a commonly used biocide known to be neurotoxic in vitro. Brief exposure of cortical neurons in culture to MIT results in increased neurodegeneration, whereas chronic exposure of developing neurons in culture to low concentrations of MIT has been shown to interfere with normal neurite outgrowth. However, the effects of chronic MIT exposure on the developing nervous system have not been tested in vivo. Here we expose Xenopus laevis tadpoles to sub-lethal concentrations of MIT during a critical period in neural development. We find that MIT exposure results in deficits in visually mediated avoidance behavior and increased susceptibility to seizures, as well electrophysiological abnormalities in optic tectal function, without any effects on overall morphology, gross anatomy of the visual projections, overall visual function, and swimming ability. These effects indicate that chronic exposure to low levels of MIT results in neural circuit-level deficits that result in abnormal neurological function without causing increased mortality or even gross anatomical defects. Our findings, combined with the fact that the long-term neurological impacts of environmental exposure to MIT have not been determined, suggest a need for a closer evaluation of the safety of MIT in commercial and industrial products.
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Affiliation(s)
- A Spawn
- Department of Neuroscience, Box G-LN, Brown University, Providence, RI 02912, USA
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9
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Gerbino A, Debellis L, Caroppo R, Curci S, Colella M. Cadmium inhibits acid secretion in stimulated frog gastric mucosa. Toxicol Appl Pharmacol 2010; 245:264-71. [DOI: 10.1016/j.taap.2010.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 03/12/2010] [Accepted: 03/15/2010] [Indexed: 12/12/2022]
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10
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Biomonitoring: an appealing tool for assessment of metal pollution in the aquatic ecosystem. Anal Chim Acta 2007; 606:135-50. [PMID: 18082645 DOI: 10.1016/j.aca.2007.11.018] [Citation(s) in RCA: 390] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Revised: 11/07/2007] [Accepted: 11/07/2007] [Indexed: 11/20/2022]
Abstract
Wide occurrence of aquatic metal pollution has caused much attention. Biomonitoring offers an appealing tool for the assessment of metal pollution in aquatic ecosystem. The bioindicators including algae, macrophyte, zooplankton, insect, bivalve mollusks, gastropod, fish, amphibian and others are enumerated and compared for their advantages and disadvantages in practical biomonitoring of aquatic metal pollution. The common biomonitoring techniques classified as bioaccumulation, biochemical alterations, morphological and behavior observation, population- and community-level approaches and modeling are discussed. The potential applications of biomonitoring are proposed to mainly include evaluation of actual aquatic metal pollution, bioremediation, toxicology prediction and researches on toxicological mechanism. Further perspectives are made for the biomonitoring of metal pollution in aquatic ecosystem.
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11
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Venturino A, Rosenbaum E, Caballero de Castro A, Anguiano OL, Gauna L, Fonovich de Schroeder T, Pechen de D'Angelo AM. Biomarkers of effect in toads and frogs. Biomarkers 2003; 8:167-86. [PMID: 12944171 DOI: 10.1080/1354700031000120116] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Amphibians are good bioindicators of environmental pollution due to their susceptibility to chemicals during their freshwater cycles. The effects of environmental pollution, together with changes in human activity and climate, have contributed to the reduction in the amphibian population over recent decades. However, toxicological research on amphibians has been rather scarce compared with that on other vertebrates. In this article we review the biochemical alterations underlying xenobiotic action and/or the detoxifying responses described for anuran species, with the aim of establishing possible biomarkers of effect. During the embryonic development of anurans, morphological and behavioural alterations are the effects most frequently cited in connection with chemical exposures. However, such biomarkers have a low sensitivity and are unspecific compared with biochemical alterations. Some primary pesticide targets, in particular cholinesterases for organophosphates and carbamates, have been evaluated. Esterases change seasonally and with the stage of development, and their sensitivity to anticholinesterase agents varies between species. Thus their use as biomarkers in anurans must be carefully analysed. Enzymes and endogenous compounds related to oxidative metabolism may also be used as biomarkers of effect. Glutathione pool, glutathione-S-transferases and metallothioneins respond in different ways to pesticides and heavy metals in anuran embryos and tadpoles. Mixed-function oxidases, in turn, are less developed in amphibians, and show a reduced induction in response to pesticide exposures. Endogenous polyamine levels are also proposed as good age-related biomarkers of damage. Finally, molecular biomarkers related to receptor binding, signal transduction and genetic response have gained increasing relevance, as they have been implicated in the fertilisation process and the earliest events in anuran development. The identification of transcription factors associated with the exposure of amphibians to xenobiotics as well as other alterations in hormone signalling appears highly promising. However, these techniques are likely to complement other methods. In conclusion, the use of several biomarkers with multiple endpoints is needed to link exposure to response and to provide better predictive tools for the environmental protection of endangered anuran species.
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Affiliation(s)
- Andrés Venturino
- Cátedra de Química Biológica, Facultad de Ciencias Agrarias, Universidad Nacional del Comahue, Buenos Aires 1400-8300 Neuquén, Argentina.
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12
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Plowman MC, Grbac-Ivankovic S, Martin J, Hopfer SM, Sunderman FW. Malformations persist after metamorphosis of Xenopus laevis tadpoles exposed to Ni2+, Co2+, or Cd2+ in FETAX assays. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 1994; 14:135-44. [PMID: 7940405 DOI: 10.1002/tcm.1770140305] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This study was performed to determine whether malformations induced in Xenopus laevis embryos by exposures to divalent nickel, cobalt, or cadmium chlorides in FETAX assays persist after the tadpoles undergo metamorphosis to juvenile frogs. Embryos were exposed for four days to EC50 concentrations of Ni2+, Co2+, or Cd2+ under the standard conditions of FETAX assays; thereafter, the exposures were discontinued and the tadpoles were kept in aquaria through metamorphosis. Controls were treated similarly, without exposure to metals. At 13 weeks of age, surviving frogs were killed and examined for malformations. Control and metal-exposed groups of Xenopus did not differ significantly in their median ages at metamorphosis, mean body weights, or survival at 13 weeks. Overall incidences of malformations found in Ni(2+)-, Co(2+)-, or Cd(2+)-exposed frogs at 13 weeks of age were 55, 40, and 51%, respectively (P < 0.01 vs. 3% in controls). The malformations of metal-exposed frogs included retinal depigmentation, diastematomyelia, scoliosis, kyphosis, phocomelia, sacro-pelvic and hind-limb deformities, and dysplasia of the heart, kidney, ovary and gut.
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Affiliation(s)
- M C Plowman
- Department of Laboratory Medicine, University of Connecticut School of Medicine, Farmington 06030-2225
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13
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Sakamoto MK, Mima S, Kihara T, Matsuo T, Yasuda Y, Tanimura T. Developmental toxicity of caffeine in the larvae of Xenopus laevis. TERATOLOGY 1993; 47:189-201. [PMID: 8475462 DOI: 10.1002/tera.1420470303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To examine the developmental toxicity of caffeine, Xenopus larvae just after hatching, were continuously exposed to 100-2,000 mg/L caffeine for 48 hours. Caffeine interfered with development of Xenopus larvae at a concentration of 100 mg/L and above in a concentration-dependent manner. Characteristic external abnormalities, such as shortened body with wavy fins, were observed, the severity of which was clearly concentration dependent. These larvae were frequently accompanied by abnormal body flexure and edema in the fin. Light microscopy revealed that exposure to caffeine induced severe damage in the myotome and neural tube, and at higher concentrations, the epidermal tissue was also affected. Myoblasts showed wide intercellular spaces, and their cytoplasm lost uniform staining. Ultrastructural studies of myoblasts revealed distinct myofibril disorganization and degeneration, and mitochondrial alterations. In the neural tube, cells at the dorsal part of tube showed wide intercellular spaces and some of them were segregated to the peripheral region. Furthermore, vacuole-like structures of various sizes appeared in the white matter. The outer layer of epithelial cells in the epidermis were vacuolated and swollen. With regard to the pathogenesis of myofibril damage, caffeine appeared to cause a disturbance of intracellular calcium regulation, by releasing calcium ions from the sarcoplasmic reticulum, and the mitochondrial changes observed in myotomal cells were considered to be reflective of this increased intracellular calcium ion levels. It is speculated that caffeine interferes with cell adhesion in the myotome and neural tube by affecting calcium ion regulation.
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Affiliation(s)
- M K Sakamoto
- Department of Anatomy, Kinki University School of Medicine, Osaka, Japan
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14
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Oberemm A, Kirschbaum F. Valproic acid induced abnormal development of the central nervous system of three species of amphibians: Implications for neural tube defects and alternative experimental systems. ACTA ACUST UNITED AC 1992; 12:251-62. [PMID: 1363963 DOI: 10.1002/tcm.1770120603] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Embryos of Ambystoma mexicanum, Xenopus laevis, and Hyperolius viridiflavus taeniatus were exposed to various concentrations of valproic acid (VPA: 0.1, 1.5, 10 mM) from blastula stage (S) 9 on up to advanced gastrulation of control embryos (S 11 1/2-12). At 10 and 5 mM VPA early development was affected in all species tested. However, the most pronounced effects occurred in Ambystoma: the neural folds appeared delayed and showed a flattened and wavy shape; the neural tube was not formed and embryos successively died. In Xenopus and Hyperolius (10, 5 mM VPA) the beginning of gastrulation was delayed up to neurulation of control embryos. In Xenopus many of the embryos completed neurulation, whereas some embryos exposed to 10 mM VPA showed neural tube defects (NTDs) of different type and degree (open neural tube at different regions of the dorsum). In Hyperolius neural folds arose around the blastoporus and fused later on (earlier in embryos treated with 5 mM VPA), but the shape of these embryos was abnormal and the development was not continued (pronounced effect at 10 mM VPA). Comparing the three species, Xenopus proved to be the least sensitive species (at 5 mM VPA 14.2% NTDs of total malformations compared to 100% in the other species). The most sensitive species, Ambystoma, developed head-oedema at 1 mM VPA, whereas the anurans were not affected. Our results suggest a similar mechanism of VPA-induced NTDs in mammals and amphibians.
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Affiliation(s)
- A Oberemm
- Institut für Toxikologie und Embryopharmakologie, Berlin, Federal Republic of Germany
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15
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Kay HH, Herfkens RJ, Kay BK. Effect of magnetic resonance imaging on Xenopus laevis embryogenesis. Magn Reson Imaging 1988; 6:501-6. [PMID: 2465471 DOI: 10.1016/0730-725x(88)90124-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Xenopus laevis embryos, exposed to various lengths of magnetic resonance imaging (MRI), demonstrated no abnormal morphology, function, or developmental delays. The overall protein profiles and nucleic acid ratios were similar compared to controls. Results suggest there are no adverse effects of MRI components on the development of this vertebrate.
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Affiliation(s)
- H H Kay
- Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, N.C
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16
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Affiliation(s)
- E M Faustman
- Department of Environmental Health, University of Washington, Seattle 98195
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17
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Birch WX, Prahlad KV. Effects of nabam on developing Xenopus laevis embryos: minimum concentration, biological stability, and degradative products. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 1986; 15:637-45. [PMID: 3789809 DOI: 10.1007/bf01054910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
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18
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Fulton MH, Chambers JE. The toxic and teratogenic effects of selected organophosphorus compounds on the embryos of three species of amphibians. Toxicol Lett 1985; 26:175-80. [PMID: 4035710 DOI: 10.1016/0378-4274(85)90163-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The toxic and teratogenic effects of 4 organophosphorus compounds (phenyl saliginen cyclic phosphate (PSCP), leptophos-oxon (LPTO), tri-o-tolyl phosphate (TOTP), and paraoxon (PXN] were investigated in the embryos of 3 species of frogs. Developmental abnormalities were observed in surviving embryos of each of the 3 species following exposure to PSCP at concentrations as low as 500 ppb for 24 h. LPTO, while being toxic to gray treefrog embryos at concentrations as low as 2.2 ppm, did not induce developmental abnormalities. TOTP and PXN were neither toxic nor teratogenic at concentrations of 10 ppm and 100 ppm respectively.
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19
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Courchesne CL, Bantle JA. Analysis of the activity of DNA, RNA, and protein synthesis inhibitors on Xenopus embryo development. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 1985; 5:177-93. [PMID: 2866601 DOI: 10.1002/tcm.1770050306] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The teratogenic and growth-inhibiting potential of DNA, RNA, and protein synthesis inhibitors was explored using the Frog Embryo Teratogenesis Assay: Xenopus (FETAX). Endpoints measured in 96-h static tests were survival, malformation, ability to swim, skin pigmentation, stage of development, and growth. The DNA synthesis inhibitors hydroxyurea, cytosine arabinoside, and ethidium bromide proved to be teratogenic by the severity of malformations induced. Hydroxyurea gave an LC50 of 1.82 mg/ml, an EC50 (malformation) of 0.43 mg/ml, while the values for cytosine arabinsode were 5.41 and 0.76, respectively. The values for ethidium bromide were 0.05 and 0.035. The RNA synthesis inhibitor actinomycin D and the protein synthesis inhibitor cycloheximide were more embryolethal than teratogenic but significantly inhibited growth as determined by head-tail length measurements. Actinomycin D caused severe malformations, while cycloheximide caused relatively minor abnormalities. The LC50 for actinomycin D was 1.89 mg/ml, while the EC50 (malformation) was 2.17 mg/ml. For cycloheximide, the values were 1.59 and 1.19, respectively. FETAX advantages include rapid data collection, the ability to measure stage-dependent effects, and the ability to use a large number of embryos to obtain excellent dose-response curves with narrow confidence limits. Disadvantages include lack of a metabolic activation system, absence of a placental relationship, and the inability to detect specific abnormalities such as limb defects in 96 h.
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