Automated zebrafish chorion removal and single embryo placement: optimizing throughput of zebrafish developmental toxicity screens (original) (raw)
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Zebrafish embryos as models for embryotoxic and teratological effects of chemicals
Reproductive Toxicology, 2009
The experimental virtues of the zebrafish embryo such as small size, development outside of the mother, cheap maintenance of the adult made the zebrafish an excellent model for phenotypic genetic and more recently also chemical screens. The availability of a genome sequence and several thousand mutants and transgenic lines together with gene arrays and a broad spectrum of techniques to manipulate gene functions add further to the experimental strength of this model. Pioneering studies suggest that chemicals can have in many cases very similar toxicological and teratological effects in zebrafish embryos and humans. In certain areas such as cardiotoxicity, the zebrafish appears to outplay the traditional rodent models of toxicity testing. Several pilot projects used zebrafish embryos to identify new chemical entities with specific biological functions. In combination with the establishment of transgenic sensor lines and the further development of existing and new automated imaging systems, the zebrafish embryos could therefore be used as cost-effective and ethically acceptable animal models for drug screening as well as toxicity testing.
The zebrafish embryo model in toxicology and teratology, September 2–3, 2010, Karlsruhe, Germany
Reproductive Toxicology, 2011
The use of fish embryos is gaining popularity for research in the area of toxicology and teratology. Particularly embryos of the zebrafish offer an array of different applications ranging from regulatory testing to mechanistic research. For this reason a consortium of two research centres and a company with the support of the COST Action EuFishBiomed has organised the Workshop "The zebrafish embryo model in toxicology and teratology", in Karlsruhe, Germany, 2nd-3rd September 2010. The workshop aimed at bringing together experts from different areas of toxicology using the (zebra)fish embryo and stimulating networking between scientists and representatives from regulatory bodies, research institutions and industry. Recent findings, presented in various platform presentations in the area of regulatory toxicity, high throughput screening, toxicogenomics, as well as environmental and human risk assessment are highlighted in this meeting report. Furthermore, the constraints and possibilities of the model as discussed at the workshop are described. A follow up-meeting was appreciated by the about 120 participants and is planned for 2012.
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 2011
Prior to hatching, the zebrafish embryo is surrounded by an acellular envelope, the chorion. Despite repeated speculations, it could not be clarified unequivocally whether the chorion represents an effective barrier and, thus, protects the embryo from exposure to distinct chemicals. Potentially, there is a risk of generating false negative results in developmental toxicity studies due to limited permeability of the chorion for some compounds. The simplest way to exclude this is to remove the chorion and expose the "naked" embryo. In the context of ecotoxicity testing, standardized protocols do not exist for fish embryo dechorionation, and survival rates of dechorionated embryos have usually not been subjected to statistical analysis. Since reproducibly high survival rates are of fundamental importance for chemical toxicity assessment, the present study was designed to develop and optimize a dechorionation procedure. With appropriate modifications of the fish embryo test protocol, embryos can be dechorionated at 24 h post-fertilization (hpf) with survival rates of ≥ 90%. However, for fish embryo tests with dechorionated embryos, the standard positive control test substance, 3,4-dichloroaniline, should be replaced by another compound, e.g., acetone, since 3,4-dichloroaniline exerts its effects during the first 24 h of development. Dechorionation of younger stages (b24 hpf) is generally possible, however with lower survival rates. The effect of dechorionation was demonstrated with the cationic polymer Luviquat HM 552, which is blocked by the chorion non-dechorionated embryos due to its molecular weight of~400,000 Dalton, but becomes strongly toxic after dechorionation.
Reproductive Toxicology, 2015
In the last couple of years, the interest in the zebrafish embryotoxicity test (ZET) for use in developmental toxicity assessment has been growing exponentially. This is also evident from the recent proposal for updating the ICHS5 guideline. The methodology of the ZET used by the different groups varies greatly. To further evaluate its successfulness and to take the ZET to the next level, harmonization of procedures is crucial. In the present study, based on literature and empirical data, the most optimal study design regarding temperature, test chamber, exposure period, presence of chorion, solvent use, exposure method, choice of concentrations, and teratogenic classification is proposed. Furthermore, our morphology scoring system is reported in detail as protocol to further enhance study design harmonization.
Characterizing sources of variability in zebrafish embryo screening protocols_suppl
ALTEX, 2018
cial use. The need for toxicity information on these chemicals is driving interest in adopting test methods with higher throughput (Tice et al., 2013; Bugel et al., 2014). In response to a number of factors, including the National Research Council report Toxicity Testing in the 21 st Century (NRC, 2007), testing initiatives such as the U.S. government's interagency Tox21 project (Attene-Ramos et al., 2013; Tice et al., 1 Introduction Traditional mammalian toxicity tests are time-intensive, expensive, and require both large amounts of test chemical and large numbers of animals (NRC, 2007; Rovida and Hartung, 2009). The cost and time needed to conduct these tests may limit the toxicity data available for the thousands of chemicals in commer
Improving Production of Zebra Fish Embryos in the Lab
Journal of Environmental Protection, 2011
The utilization of fish embryos in toxicity testing of hazardous chemicals has recently been adopted in order to satisfy stricter rules and regulations related to using adult animals in toxicity testing. This paper presents optimising steps towards improving zebra ...
Cell Biology International, 2020
Zebrafish (Danio rerio), is a well-established vertebrate animal model widely used in developmental biology and toxicological research. In the present study, foldscope is used as an innovative tool to study the developmental stages and toxicological analysis of the Zebrafish embryos. Briefly, the developmental stages such as zygote, cleavage, blastula, gastrula, segmentation and pharyngula formation are observed and documented using simple foldscope. Toxicological parameters upon exposure to different concentration of ethanol extract of Curcuma longa and its lead compound, ar-turmerone along with Rhodamine B (bio-coupler) on Zebrafish embryos are analyzed upto 72 h using foldscopes in live condition. The lethal endpoints such as coagulation, lack of somite formation, non-detachment of tail, and lack of heartbeat are clearly monitored and documented using foldscope. Bio-evaluation of test compounds with the aid of foldscope confirms that the toxicity is directly proportional to the concentration. Our results conclude that, ethanol extract of C.longa, ar-turmerone and Rhodamine B exposed embryos remains healthy up to 96 µg, 48 µg and 24 µg concentrations, respectively. Embryos exposed to higher concentrations become coagulated, however normal physiological active movement of tail lashing and heartbeat are evident in lower concentration exposed embryos. Except coagulation, no other abnormalities are observed and interestingly, the hatching ability is not delayed, when compared to the control embryos. It is confirmed that the test compounds are not highly toxic to Zebrafish This article is protected by copyright. All rights reserved. Accepted Article embryos. Hence it can be used for further analysis, especially for studying the neuralregeneration and its neuronal development in Zebrafish embryos.