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Gölz L, Blanc-Legendre M, Rinderknecht M, Behnstedt L, Coordes S, Reger L, Sire S, Cousin X, Braunbeck T, Baumann L. Development of a Zebrafish Embryo-Based Test System for Thyroid Hormone System Disruption: 3Rs in Ecotoxicological Research. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2024. [PMID: 38804632 DOI: 10.1002/etc.5878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/05/2024] [Accepted: 03/25/2024] [Indexed: 05/29/2024]
Abstract
There is increasing concern regarding pollutants disrupting the vertebrate thyroid hormone (TH) system, which is crucial for development. Thus, identification of TH system-disrupting chemicals (THSDCs) is an important requirement in the Organisation for Economic Co-operation and Development (OECD) testing framework. The current OECD approach uses different model organisms for different endocrine modalities, leading to a high number of animal tests. Alternative models compatible with the 3Rs (replacement, reduction, refinement) principle are required. Zebrafish embryos, not protected by current European Union animal welfare legislation, represent a promising model. Studies show that zebrafish swim bladder inflation and eye development are affected by THSDCs, and the respective adverse outcome pathways (AOPs) have been established. The present study compared effects of four THSDCs with distinct molecular modes of action: Propylthiouracil (PTU), potassium perchlorate, iopanoic acid, and the TH triiodothyronine (T3) were tested with a protocol based on the OECD fish embryo toxicity test (FET). Effects were analyzed according to the AOP concept from molecular over morphological to behavioral levels: Analysis of thyroid- and eye-related gene expression revealed significant effects after PTU and T3 exposure. All substances caused changes in thyroid follicle morphology of a transgenic zebrafish line expressing fluorescence in thyrocytes. Impaired eye development and swimming activity were observed in all treatments, supporting the hypothesis that THSDCs cause adverse population-relevant changes. Findings thus confirm that the FET can be amended by TH system-related endpoints into an integrated protocol comprising molecular, morphological, and behavioral endpoints for environmental risk assessment of potential endocrine disruptors, which is compatible with the 3Rs principle. Environ Toxicol Chem 2024;00:1-18. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Lisa Gölz
- Aquatic Ecology & Toxicology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
- Current affiliation: Institute of Pharmacology, University of Heidelberg, Heidelberg, Germany
| | | | - Maximilian Rinderknecht
- Aquatic Ecology & Toxicology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Laura Behnstedt
- Aquatic Ecology & Toxicology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Sara Coordes
- Aquatic Ecology & Toxicology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Luisa Reger
- Aquatic Ecology & Toxicology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Sacha Sire
- MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, INRAE, Palavas, France
| | - Xavier Cousin
- MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, INRAE, Palavas, France
| | - Thomas Braunbeck
- Aquatic Ecology & Toxicology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Lisa Baumann
- Aquatic Ecology & Toxicology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
- Current affiliation: Amsterdam Institute for Life and Environment, Section Environmental Health & Toxicology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Gölz L, Pannetier P, Fagundes T, Knörr S, Behnstedt L, Coordes S, Matthiessen P, Morthorst J, Vergauwen L, Knapen D, Holbech H, Braunbeck T, Baumann L. Development of the integrated fish endocrine disruptor test-Part B: Implementation of thyroid-related endpoints. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2024; 20:830-845. [PMID: 37578010 DOI: 10.1002/ieam.4828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/21/2023] [Accepted: 08/10/2023] [Indexed: 08/15/2023]
Abstract
Given the vital role of thyroid hormones (THs) in vertebrate development, it is essential to identify chemicals that interfere with the TH system. Whereas, among nonmammalian laboratory animals, fish are the most frequently utilized test species in endocrine disruptor research, for example, in guidelines for the detection of effects on the sex hormone system, there is no test guideline (TG) using fish as models for thyroid-related effects; rather, amphibians are used. Therefore, the objective of the present project was to integrate thyroid-related endpoints for fish into a test protocol combining OECD TGs 229 (Fish Short-Term Reproduction Assay) and 234 (Fish Sexual Development Test). The resulting integrated Fish Endocrine Disruption Test (iFEDT) was designed as a comprehensive approach to covering sexual differentiation, early development, and reproduction and to identifying disruption not only of the sexual and/or reproductive system but also the TH system. Two 85-day exposure tests were performed using different well-studied endocrine disruptors: 6-propyl-2-thiouracil (PTU) and 17α-ethinylestradiol (EE2). Whereas the companion Part A of this study presents the findings on effects by PTU and EE2 on endpoints established in existing TGs, the present Part B discusses effects on novel thyroid-related endpoints such as TH levels, thyroid follicle histopathology, and eye development. 6-Propyl-2-thiouracil induced a massive proliferation of thyroid follicles in any life stage, and histopathological changes in the eyes proved to be highly sensitive for TH system disruption especially in younger life stages. For measurement of THs, further methodological development is required. 17-α-Ethinylestradiol demonstrated not only the well-known disruption of the hypothalamic-pituitary-gonadal axis, but also induced effects on thyroid follicles in adult zebrafish (Danio rerio) exposed to higher EE2 concentrations, suggesting crosstalk between endocrine axes. The novel iFEDT has thus proven capable of simultaneously capturing endocrine disruption of both the steroid and thyroid endocrine systems. Integr Environ Assess Manag 2024;20:830-845. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
- Lisa Gölz
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Pauline Pannetier
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
- Laboratoire de Ploufragan-Plouzané-Niort, Site de Plouzané, Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail, Plouzané, France
| | - Teresa Fagundes
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Susanne Knörr
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Laura Behnstedt
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Sara Coordes
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | | | - Jane Morthorst
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Lucia Vergauwen
- Department of Veterinary Sciences, Veterinary Physiology and Biochemistry, Zebrafishlab, University of Antwerp, Wilrijk, Belgium
| | - Dries Knapen
- Department of Veterinary Sciences, Veterinary Physiology and Biochemistry, Zebrafishlab, University of Antwerp, Wilrijk, Belgium
| | - Henrik Holbech
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Thomas Braunbeck
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Lisa Baumann
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
- Amsterdam Institute for Life and Environment (A-LIFE), Section Environmental Health & Toxicology, Vrije Universiteit Amsterdam, HV Amsterdam, The Netherlands
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Colque-Caro LA, Acuña F, Aguirre LS, Avellaneda-Cáceres A, Barbeito CG, Signorini M, Moore DP, Micheloud JF. Characterization of lesions of nutritional congenital goitre in cattle. J Comp Pathol 2023; 206:1-8. [PMID: 37716230 DOI: 10.1016/j.jcpa.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 04/04/2023] [Accepted: 08/18/2023] [Indexed: 09/18/2023]
Abstract
There are few studies that classify and characterize the morphometric and immunohistochemical features of goitre in bovine thyroid glands (TGs). We investigated 39 bovine TGs (fetuses [9], stillbirths [18], neonates [12]) born to dams with low T4 hormone levels and no iodine supplementation and 10 (fetuses [3], stillbirths [3], neonates [4]) born to dams with normal T4 levels and supplemented with iodine. Body weight (BW), TG weight (TGW), TGW:BW ratio and histological lesions were determined. The TGs were classified histopathologically as normal gland (G0), mild goitre (G1), moderate goitre (G2) or severe goitre (G3). Various morphological and morphometric parameters were calculated from microscopic images using image analysis software. Immunohistochemistry was performed to detect proliferating cell nuclear antigen (PCNA). There were significant differences in the TGW:BW ratio among groups (P <0.05): 0.3 ± 0.1 in G0, 0.5 ± 0.3 in G1, 0.8 ± 0.3 in G2 and 1.3 ± 0.7 in G3. In G0, large homogeneous follicles with eosinophilic colloid were seen. In the groups with lesions (G1, G2 and G3), heterogeneity in follicle shape and size, height and area of thyroid follicular cells, height of thyroid follicular epithelium and PCNA immunolabelling were directly related to histopathological grade, with significant differences among groups (P <0.001), gradually increasing from G1 to G3 compared with G0. The TGW:BW ratio and histological grade were positively correlated (P = 0.008).
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Affiliation(s)
- Luis A Colque-Caro
- Área de Sanidad Animal "Dr. Bernardo Jorge Carrillo" Instituto de Investigación Animal Chaco Semiárido, CIAP, Instituto Nacional de Tecnología Agropecuaria (INTA), Ruta Nac. 68 - Km 172, Salta, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT SALTA - JUJUY, Rivadavia 941, Salta, Argentina.
| | - Francisco Acuña
- Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Av. 60 y 118, B1900 La Plata, Buenos Aires, Argentina; CONICET CCT La Plata, Calle 8 Nº 1467, La Plata, Buenos Aires, Argentina
| | - Laura S Aguirre
- Área de Sanidad Animal "Dr. Bernardo Jorge Carrillo" Instituto de Investigación Animal Chaco Semiárido, CIAP, Instituto Nacional de Tecnología Agropecuaria (INTA), Ruta Nac. 68 - Km 172, Salta, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT SALTA - JUJUY, Rivadavia 941, Salta, Argentina
| | - Agustín Avellaneda-Cáceres
- Área de Sanidad Animal "Dr. Bernardo Jorge Carrillo" Instituto de Investigación Animal Chaco Semiárido, CIAP, Instituto Nacional de Tecnología Agropecuaria (INTA), Ruta Nac. 68 - Km 172, Salta, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT SALTA - JUJUY, Rivadavia 941, Salta, Argentina
| | - Claudio G Barbeito
- Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Av. 60 y 118, B1900 La Plata, Buenos Aires, Argentina; CONICET CCT La Plata, Calle 8 Nº 1467, La Plata, Buenos Aires, Argentina
| | - Marcelo Signorini
- Instituto de Investigación de la Cadena Láctea (INTA - CONICET), Ruta Nacional 34, Km 227, Rafaela, Santa Fe, Argentina
| | - Dadin P Moore
- Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible, INTA-CONICET, 7620 Balcarce, Buenos Aires, Argentina; Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, 7620 Balcarce, Argentina
| | - Juan F Micheloud
- Área de Sanidad Animal "Dr. Bernardo Jorge Carrillo" Instituto de Investigación Animal Chaco Semiárido, CIAP, Instituto Nacional de Tecnología Agropecuaria (INTA), Ruta Nac. 68 - Km 172, Salta, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) CCT SALTA - JUJUY, Rivadavia 941, Salta, Argentina; Facultad de Ciencias Agrarias y Veterinarias, Universidad Católica de Salta, Campus Castañares, Salta, Argentina
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Pannetier P, Poulsen R, Gölz L, Coordes S, Stegeman H, Koegst J, Reger L, Braunbeck T, Hansen M, Baumann L. Reversibility of Thyroid Hormone System-Disrupting Effects on Eye and Thyroid Follicle Development in Zebrafish (Danio rerio) Embryos. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2023; 42:1276-1292. [PMID: 36920003 DOI: 10.1002/etc.5608] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/13/2022] [Accepted: 03/10/2023] [Indexed: 05/27/2023]
Abstract
Early vertebrate development is partially regulated by thyroid hormones (THs). Environmental pollutants that interact with the TH system (TH system-disrupting chemicals [THSDCs]) can have massively disrupting effects on this essential phase. Eye development of fish is directly regulated by THs and can, therefore, be used as a thyroid-related endpoint in endocrine disruptor testing. To evaluate the effects of THSDC-induced eye malformations during early development, zebrafish (Danio rerio) embryos were exposed for 5 days postfertilization (dpf) to either propylthiouracil, a TH synthesis inhibitor, or tetrabromobisphenol A, which interacts with TH receptors. Subsequently, one half of the embryos were exposed further to the THSDCs until 8 dpf, while the other half of the embryos were raised in clean water for 3 days to check for reversibility of effects. Continued THSDC exposure altered eye size and pigmentation and induced changes in the cellular structure of the retina. This correlated with morphological alterations of thyroid follicles as revealed by use of a transgenic zebrafish line. Interestingly, effects were partly reversible after a recovery period as short as 3 days. Results are consistent with changes in TH levels measured in different tissues of the embryos, for example, in the eyes. The results show that eye development in zebrafish embryos is very sensitive to THSDC treatment but able to recover quickly from early exposure by effective repair mechanisms. Environ Toxicol Chem 2023;42:1276-1292. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Pauline Pannetier
- Aquatic Ecology & Toxicology, Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Rikke Poulsen
- Environmental Metabolomics Laboratory, Department of Environmental Science, University of Aarhus, Aarhus, Denmark
| | - Lisa Gölz
- Aquatic Ecology & Toxicology, Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Sara Coordes
- Aquatic Ecology & Toxicology, Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Hanna Stegeman
- Aquatic Ecology & Toxicology, Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Johannes Koegst
- Aquatic Ecology & Toxicology, Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Luisa Reger
- Aquatic Ecology & Toxicology, Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Thomas Braunbeck
- Aquatic Ecology & Toxicology, Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Martin Hansen
- Environmental Metabolomics Laboratory, Department of Environmental Science, University of Aarhus, Aarhus, Denmark
| | - Lisa Baumann
- Aquatic Ecology & Toxicology, Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
- Amsterdam Institute for Life and Environment (A-LIFE), Section on Environmental Health & Toxicology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Manera M, Castaldelli G, Giari L. Perfluorooctanoic Acid Affects Thyroid Follicles in Common Carp ( Cyprinus carpio). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19159049. [PMID: 35897426 PMCID: PMC9332161 DOI: 10.3390/ijerph19159049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 07/20/2022] [Indexed: 11/16/2022]
Abstract
Carp kidney is comprised of nephrons, hemopoietic tissue, and also hormonally-active thyroid follicles. Given this anatomical trait, it has been used to assess the thyroid disrupting potential of perfluorooctanoic acid (PFOA), a widespread and feared per- poly-fluoroalkyl substance and a persistent organic pollutant capable of interfering with the endocrine system in animals and humans. The occurrence and morphology of thyroid follicles in kidneys of carp experimentally exposed to 200 ng L−1 or 2 mg L−1 waterborne PFOA for 56 days were studied. The abundance of thyroid follicles was significantly higher and vesiculation increased in exposed fish as compared to controls. The number of vesiculated follicles/total number of follicles was positively correlated with PFOA blood concentration in fish exposed to the highest dose (2 mg L−1). The structure and ultrastructure of thyroid follicles were affected by PFOA also at the lower, environmentally relevant, concentration (200 ng L−1). Increased cellular projections, enhanced colloid endocytosis, rough endoplasmic reticulum enlargement and fragmentation and cytoplasm vacuolation were the main features displayed by PFOA-exposed carp. These results show that PFOA affects the occurrence and status of follicles and suggest the utility of fish kidney as a multipurpose biomarker organ in environmental pathology research, according to the One Health approach.
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Affiliation(s)
- Maurizio Manera
- Faculty of Biosciences, Food and Environmental Technologies, University of Teramo, St. R. Balzarini 1, 64100 Teramo, Italy
- Correspondence:
| | - Giuseppe Castaldelli
- Department of Environmental and Prevention Sciences, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy; (G.C.); (L.G.)
| | - Luisa Giari
- Department of Environmental and Prevention Sciences, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy; (G.C.); (L.G.)
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Aviles A, Hulgard K, Green JW, Duus A, Holbech B, Morthorst JE. Effects of sodium perchlorate and 6-propylthiouracil on metamorphosis and thyroid gland histopathology in the European common frog (Rana temporaria). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 244:106094. [PMID: 35134604 DOI: 10.1016/j.aquatox.2022.106094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 01/19/2022] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
Several chemicals have been identified as thyroid hormone axis disrupting chemicals (THADCs) able to interfere with the thyroid hormone system during fetal life and early life stages, thereby impairing neurodevelopment in mammals and inducing development and growth disorders in fish and amphibians. However, identification of THADCs is particularly challenging, and thyroid modalities are currently only assessed in vivo by mammalian and amphibian tests. The aquatic African clawed frog (Xenopus laevis/tropicalis) is the model species of the amphibian test guidelines developed by the OECD and the United States Environmental Protection Agency, but as most European amphibians are semi-aquatic, concern has been raised whether the sensitivity of native European species is comparable to Xenopus. A shortened version of the OEDC test guideline 241 (Larval Amphibian Growth and Development Assay, LAGDA) was used to investigate the effects of two model THADCs on the metamorphosis and thyroid histopathology in the European common frog (Rana temporaria). R. temporaria eggs were collected on the field and exposed till metamorphic climax to sodium perchlorate (11.9-426.5 μg/L perchlorate concentrations) and 6-propylthiouracil (PTU: 1.23-47.7 mg/L). PTU severely delayed metamorphosis and affected several thyroid gland histopathological endpoints at slightly lower concentrations compared to Xenopus. As opposed to what was described in similar Xenopus studies, we observed no effect of perchlorate on the investigated endpoints. Interspecies differences may be linked to mechanisms of action.
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Affiliation(s)
- Amandine Aviles
- Department of Biology, University of Southern Denmark, Syddansk Universitet, Odense, Denmark
| | - Katrine Hulgard
- Department of Biology, University of Southern Denmark, Syddansk Universitet, Odense, Denmark
| | - John W Green
- John W Green Ecostatistical Consulting LLC, 372 Chickory Way, Newark, DE 19711, USA
| | - Annette Duus
- Department of Biology, University of Southern Denmark, Syddansk Universitet, Odense, Denmark
| | - Bente Holbech
- Department of Biology, University of Southern Denmark, Syddansk Universitet, Odense, Denmark
| | - Jane E Morthorst
- Department of Biology, University of Southern Denmark, Syddansk Universitet, Odense, Denmark.
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Šošić-Jurjević B, Trifunović S, Živanović J, Ajdžanović V, Miler M, Ristić N, Filipović B. Vitamin D 3 Treatment Alters Thyroid Functional Morphology in Orchidectomized Rat Model of Osteoporosis. Int J Mol Sci 2022; 23:ijms23020791. [PMID: 35054977 PMCID: PMC8775693 DOI: 10.3390/ijms23020791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 01/08/2023] Open
Abstract
Vitamin D plays an essential role in prevention and treatment of osteoporosis. Thyroid hormones, in addition to vitamin D, significantly contribute to regulation of bone remodeling cycle and health. There is currently no data about a possible connection between vitamin D treatment and the thyroid in the context of osteoporosis. Middle-aged Wistar rats were divided into: sham operated (SO), orchidectomized (Orx), and cholecalciferol-treated orchidectomized (Orx + Vit. D3; 5 µg/kg b.m./day during three weeks) groups (n = 6/group). Concentration of 25(OH)D in serum of the Orx + Vit. D3 group increased 4 and 3.2 times (p < 0.0001) respectively, compared to Orx and SO group. T4, TSH, and calcitonin in serum remained unaltered. Vit. D3 treatment induced changes in thyroid functional morphology that indicate increased utilization of stored colloid and release of thyroid hormones in comparison with hormone synthesis, to maintain hormonal balance. Increased expression of nuclear VDR (p < 0.05) points to direct, TSH independent action of Vit. D on thyrocytes. Strong CYP24A1 immunostaining in C cells suggests its prominent expression in response to Vit. D in this cell subpopulation in orchidectomized rat model of osteoporosis. The indirect effect of Vit. D on bone, through fine regulation of thyroid function, is small.
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Rehberger K, Baumann L, Hecker M, Braunbeck T. Intrafollicular thyroid hormone staining in whole-mount zebrafish (Danio rerio) embryos for the detection of thyroid hormone synthesis disruption. FISH PHYSIOLOGY AND BIOCHEMISTRY 2018; 44:997-1010. [PMID: 29568982 DOI: 10.1007/s10695-018-0488-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 02/26/2018] [Indexed: 06/08/2023]
Abstract
Endocrine-disrupting chemicals are known to impact multiple hormonal axes of vertebrates, among which the thyroid system is crucial for multiple developmental and physiological processes. Thus, the present study focused on the semi-quantitative visualization of intrafollicular triiodothyronine (T3) and thyroxin (T4) in zebrafish embryos as a potential test system for the detection of disrupted thyroid hormone synthesis. To this end, an antibody-based fluorescence double-staining protocol for whole-mount zebrafish embryos and larvae was adapted to simultaneously detect intrafollicular T3 and T4. During normal development until 10 days post-fertilization (dpf), the number of thyroid follicles increased along the ventral aorta. Concentrations of T4 and T3, measured by fluorescence intensity, increased until 6 dpf, but decreased thereafter. Exposure of zebrafish embryos to propylthiouracil (PTU), a known inhibitor of TH synthesis, resulted in a significant decrease in the number of follicles that stained for T3, whereas a trend for increase in follicles that stained for T4 was observed. In contrast, fluorescence intensity for both thyroid hormones decreased significantly after exposure to PTU. Overall, the zebrafish embryo appears to be suitable for the simultaneous visualization and detection of changing intrafollicular TH contents during normal development and after PTU treatment.
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Affiliation(s)
- Kristina Rehberger
- Centre for Organismal Studies, Aquatic Ecology and Toxicology, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany
- Vetsuisse Faculty, Centre for Fish and Wildlife Health, University of Bern, Länggassstrasse122, 3012, Bern, Switzerland
| | - Lisa Baumann
- Centre for Organismal Studies, Aquatic Ecology and Toxicology, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany.
| | - Markus Hecker
- School of the Environment & Sustainability and Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK, S7N 5B3, Canada
| | - Thomas Braunbeck
- Centre for Organismal Studies, Aquatic Ecology and Toxicology, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany.
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