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Lu X, Zhang L, Lin GM, Lu JG, Cui ZB. Analysis of Differential Gene Expression under Acute Lead or Mercury Exposure in Larval Zebrafish Using RNA-Seq. Animals (Basel) 2024; 14:2877. [PMID: 39409826 PMCID: PMC11475140 DOI: 10.3390/ani14192877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2024] [Revised: 09/23/2024] [Accepted: 10/04/2024] [Indexed: 10/20/2024] Open
Abstract
This study was first conducted to investigate the effects of acute lead exposure on developing zebrafish embryos or larvae from 24 to 120 h post-fertilization (hpf). Our data showed that treatment with 50-200 μM lead significantly affected larval survivability and morphology compared to the respective control. Second, we chose 120 hpf larvae treated with 12.5 μM lead for RNA sequencing due to its exposure level being sufficient to produce toxic effects with minimum death and lead bioaccumulation in developing zebrafish. A total of 137.45 million raw reads were obtained, and more than 86% of clean data were mapped to the zebrafish reference genome. Differential expression profiles generated 116 up- and 34 down-regulated genes upon lead exposure. The most enriched GO terms for representative DEGs were ion transport and lipid metabolism. Third, a comparison with the dataset of mercury-regulated gene expression identified 94 genes (64 up-regulated and 30 down-regulated) for exposure specific to lead, as well as 422 genes (338 up-regulated and 84 down-regulated) for exposure specific to mercury. In addition, 56 genes were co-regulated by micromolar mercury and lead treatment, and the expression of thirteen genes, including mt2, ctssb.1, prdx1, txn, sqrdl, tmprss13a, socs3a, trpv6, abcb6a, gsr, hbz, fads2, and zgc:92590 were validated by qRT-PCR. These genes were mainly associated with metal ion binding, proteolysis, antioxidant activity, signal transduction, calcium ion or oxygen transport, the fatty acid biosynthetic process, and protein metabolism. Taken together, these findings help better understand the genome-wide responses of developing zebrafish to lead or mercury and provide potential biomarkers for acute exposure to toxic metals.
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Affiliation(s)
- Xing Lu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Lang Zhang
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China;
| | - Gen-Mei Lin
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (G.-M.L.); (J.-G.L.)
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, China
| | - Jian-Guo Lu
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (G.-M.L.); (J.-G.L.)
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, China
| | - Zong-Bin Cui
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
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Qiu X, Zhang Y, Gao J, Cui Y, Dong K, Chen K, Shi Y. Exposure to thimerosal induces behavioral abnormality in the early life stages of zebrafish via altering amino acid homeostasis. JOURNAL OF HAZARDOUS MATERIALS 2024; 478:135548. [PMID: 39154483 DOI: 10.1016/j.jhazmat.2024.135548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 08/08/2024] [Accepted: 08/15/2024] [Indexed: 08/20/2024]
Abstract
Thimerosal (THI) has become a significant source of organic mercury pollutants in aquatic ecosystems, but there is limited information regarding its adverse effects on fish. In this study, zebrafish embryos were exposed to THI at 0 (control), 5.0, and 50 ng/L from 0-5 days post fertilization (dpf), and variations in their survival, development, behavior, free amino acid contents, and the biochemical responses involved in monoaminergic systems were examined. Although THI exposure did not significantly affect the survival, heart rate, or hatching time of zebrafish embryos, it substantially increased swimming velocity (136-154 % of the control) and reduced exploratory behavior (141-142 % of the control) in zebrafish larvae at 5 dpf. Exposure also significantly altered the amino acid contents (51-209 % of the control) and monoamine levels (70-154 % of the control) in zebrafish larvae, some of which displayed significant correlations with behavioral traits. THI significantly elevated dopamine receptor gene expression and monoamine oxidase activity in zebrafish larvae. Adding extra phenylalanine or tryptophan to the E3 medium facilitates the recovery of zebrafish larvae from the abnormal behaviors induced by THI. These findings reveal for the first time that THI exposure at the level of ng/L is sufficient to induce neurobehavioral toxic effects in the early life stages of zebrafish, and disrupting amino acid homeostasis is a critical underlying mechanism. This study provides valuable insights into the toxicity of THI to fish and highlights the importance of assessing its potential risks to aquatic ecosystems.
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Affiliation(s)
- Xuchun Qiu
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, China.
| | - Yibing Zhang
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Jiarui Gao
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Yiming Cui
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Kejun Dong
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Kun Chen
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Yanhong Shi
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
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Li L, Dong K, Li L, Li Q, Su Y, Zong C. Adverse effects of thimerosal on the early life stages of zebrafish. Comp Biochem Physiol C Toxicol Pharmacol 2024; 287:110046. [PMID: 39307513 DOI: 10.1016/j.cbpc.2024.110046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 09/05/2024] [Accepted: 09/19/2024] [Indexed: 09/26/2024]
Abstract
Thimerosal (THI) is an organic mercury compound that is widely used in drugs, vaccines and antibacterial products. Its extensive production and use have resulted in significant environmental contamination, posing a considerable threat to aquatic life. However, the knowledge of the toxicity of THI to aquatic organisms is still insufficient. In this study, we conducted a 5-day THI exposure experiment using zebrafish, from 0 to 5 days post fertilization (dpf). The possible adverse effects of THI on the early-life stages of zebrafish were explored by investigating variations in their physiological parameters, behavioral traits, and neurotransmitter levels. The results showed THI exhibited significant developmental toxicity to aquatic organisms. Exposure to THI significantly induced serious malformation (at 50 μg/L), accelerated hatching, and elevated heart rate (at 5 and 50 μg/L). The behavioral traits of zebrafish larvae had an increased first and then decreased relationship with increasing concentration of THI, which induced hyperactivity at 0.5 μg/L but opposite at 50 μg/L. Furthermore, exposure to 50 μg/L THI significantly raised levels of 5-HT, 5-HIAA, DA, DOPAC and ACH in zebrafish larvae. In addition, several significant correlations between behavioral traits and the neurotransmitter contents were detected, which seemed to reveal an important mechanism of the neurobehavioral toxicity of THI to fish.
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Affiliation(s)
- Lixia Li
- The school of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Kejun Dong
- The school of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - LeYan Li
- The school of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Qingchen Li
- College of Environment, Hohai University, Nanjing, China
| | - Youqin Su
- The school of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Chenrui Zong
- The school of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
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Aschner M, Skalny AV, Paoliello MMB, Tinkova MN, Martins AC, Santamaria A, Lee E, Rocha JBT, Farsky SHP, Tinkov AA. Retinal toxicity of heavy metals and its involvement in retinal pathology. Food Chem Toxicol 2024; 188:114685. [PMID: 38663763 DOI: 10.1016/j.fct.2024.114685] [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: 02/21/2024] [Revised: 04/16/2024] [Accepted: 04/22/2024] [Indexed: 05/04/2024]
Abstract
The objective of the present review is to discuss epidemiological evidence demonstrating the association between toxic metal (Cd, Pb, Hg, As, Sn, Ti, Tl) exposure and retinal pathology, along with the potential underlying molecular mechanisms. Epidemiological studies demonstrate that Cd, and to a lesser extent Pb exposure, are associated with age-related macular degeneration (AMD), while the existing evidence on the levels of these metals in patients with diabetic retinopathy is scarce. Epidemiological data on the association between other toxic metals and metalloids including mercury (Hg) and arsenic (As), are limited. Clinical reports and laboratory in vivo studies have shown structural alterations in different layers of retina following metal exposure. Examination of retina samples demonstrate that toxic metals can accumulate in the retina, and the rate of accumulation appears to increase with age. Experimental studies in vivo and in vitro studies in APRE-19 and D407 cells demonstrate that toxic metal exposure may cause retinal damage through oxidative stress, apoptosis, DNA damage, mitochondrial dysfunction, endoplasmic reticulum stress, impaired retinogenesis, and retinal inflammation. However, further epidemiological as well as laboratory studies are required for understanding the underlying molecular mechanisms and identifying of the potential therapeutic targets and estimation of the dose-response effects.
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Affiliation(s)
- Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Anatoly V Skalny
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, Yaroslavl, 150003, Russia; Center of Bioelementology and Human Ecology, IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, 119435, Russia
| | - Monica M B Paoliello
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | | | - Airton C Martins
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Abel Santamaria
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico; Laboratorio de Nanotecnología y Nanomedicina, Departamento de Cuidado de La Salud, Universidad Autónoma Metropolitana-Xochimilco, Mexico City 04960, Mexico
| | - Eunsook Lee
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
| | - Joao B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria 97105-900, RS, Brazil
| | - Sandra H P Farsky
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, São Paulo 05508-000, SP, Brazil
| | - Alexey A Tinkov
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, Yaroslavl, 150003, Russia; Center of Bioelementology and Human Ecology, IM Sechenov First Moscow State Medical University (Sechenov University), Moscow, 119435, Russia.
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Qiu X, Su Z, Gao J, Cui Y, Dong K, Chen K, Zhao RJ, Wang S, Wu T, Shi Y. Sex-specific impacts of thimerosal on the behaviors and brain monoaminergic systems in zebrafish (Danio rerio). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 271:106921. [PMID: 38615580 DOI: 10.1016/j.aquatox.2024.106921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 03/30/2024] [Accepted: 04/07/2024] [Indexed: 04/16/2024]
Abstract
Thimerosal (THI) is the most widely used form of organic mercury in pharmaceutical and personal care products, and has become a major source of ethylmercury pollution in aquatic ecosystems. However, knowledge about its potential risk to aquatic species is limited. In this study, zebrafish were exposed to THI for 7 days, and variations in their behavioral traits, brain monoaminergic neurotransmitter contents, and related gene expression were investigated. After the 7-day exposure, THI reduced locomotor activity and thigmotaxis in males but not females. Exposure to THI increased the social interaction between females but decreased that between males. The THI exposure also significantly reduced the serotonin (5-HT), 5-hydroxyindoleacetic acid, dopamine (DA), and 3,4-dihydroxyphenylacetic acid contents in the brain of males, but only significantly decreased the DA content in females. Correlation analysis revealed that the neurochemical alterations in the brain of zebrafish play critical roles in the behavioral abnormalities induced by THI exposure. Moreover, THI also significantly altered the expression of some genes associated with the synthesis, metabolism, and receptor binding of 5-HT and DA in the brain of zebrafish. The differences in these gene expressions between female and male zebrafish exposed to THI seem to be an important mechanism underlying their sex-specific responses to this chemical. This is the first report on the sex-specific effects of THI on behaviors and brain monoaminergic neurotransmitter contents in zebrafish, which can further improve our understanding of its toxic effects on teleost.
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Affiliation(s)
- Xuchun Qiu
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, China.
| | - Zhen Su
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Jiarui Gao
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Yiming Cui
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Kejun Dong
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Kun Chen
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Ru-Jin Zhao
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Songmei Wang
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Tao Wu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Yanhong Shi
- Institute of Environmental Health and Ecological Security, College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
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Cirqueira F, Figueirêdo LPD, Malafaia G, Rocha TL. Zebrafish neuromast sensory system: Is it an emerging target to assess environmental pollution impacts? ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123400. [PMID: 38272167 DOI: 10.1016/j.envpol.2024.123400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/29/2023] [Accepted: 01/17/2024] [Indexed: 01/27/2024]
Abstract
Environmental pollution poses risks to ecosystems. Among these risks, one finds neurotoxicity and damage to the lateral line structures of fish, such as the neuromast and its hair cells. Zebrafish (Danio rerio) is recommended as model species to be used in ecotoxicological studies and environmental biomonitoring programs aimed at assessing several biomarkers, such as ototoxicity. However, little is known about the history of and knowledge gaps on zebrafish ototoxicity. Thus, the aim of the current study is to review data available in the scientific literature about using zebrafish as animal model to assess neuromast toxicity. It must be done by analyzing the history and publication category, world production, experimental design, developmental stages, chemical classes, neuromasts and hair cell visualization methods, and zebrafish strains. Based on the results, number, survival and fluorescence intensity of neuromasts, and their hair cells, were the parameters oftentimes used to assess ototoxicity in zebrafish. The wild AB strain was the most used one, and it was followed by Tübingen and transgenic strains with GFP markers. DASPEI was the fluorescent dye most often applied as method to visualize neuromasts, and it was followed by Yo-Pro-1 and GFP transgenic lines. Antibiotics, antitumorals, metals, nanoparticles and plant extracts were the most frequent classes of chemicals used in the analyzed studies. Overall, pollutants can harm zebrafish's mechanosensory system, as well as affect their behavior and survival. Results have shown that zebrafish is a suitable model system to assess ototoxicity induced by environmental pollution.
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Affiliation(s)
- Felipe Cirqueira
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil
| | - Livia Pitombeira de Figueirêdo
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil
| | - Guilherme Malafaia
- Laboratory of Toxicology Applied to the Environment, Goiano Federal Institute - Urutaí Campus, Goiás, Brazil
| | - Thiago Lopes Rocha
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil.
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Zhao W, Chen Y, Hu N, Long D, Cao Y. The uses of zebrafish (Danio rerio) as an in vivo model for toxicological studies: A review based on bibliometrics. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 272:116023. [PMID: 38290311 DOI: 10.1016/j.ecoenv.2024.116023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/20/2024] [Accepted: 01/24/2024] [Indexed: 02/01/2024]
Abstract
An in vivo model is necessary for toxicology. This review analyzed the uses of zebrafish (Danio rerio) in toxicology based on bibliometrics. Totally 56,816 publications about zebrafish from 2002 to 2023 were found in Web of Science Core Collection, with Toxicology as the top 6 among all disciplines. Accordingly, the bibliometric map reveals that "toxicity" has become a hot keyword. It further reveals that the most common exposure types include acute, chronic, and combined exposure. The toxicological effects include behavioral, intestinal, cardiovascular, hepatic, endocrine toxicity, neurotoxicity, immunotoxicity, genotoxicity, and reproductive and transgenerational toxicity. The mechanisms include oxidative stress, inflammation, autophagy, and dysbiosis of gut microbiota. The toxicants commonly evaluated by using zebrafish model include nanomaterials, arsenic, metals, bisphenol, and dioxin. Overall, zebrafish provide a unique and well-accepted model to investigate the toxicological effects and mechanisms. We also discussed the possible ways to address some of the limitations of zebrafish model, such as the combination of human organoids to avoid species differences.
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Affiliation(s)
- Weichao Zhao
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Yuna Chen
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Nan Hu
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, PR China.
| | - Dingxin Long
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China.
| | - Yi Cao
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China.
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Henriques MC, Carvalho I, Santos C, Herdeiro MT, Fardilha M, Pavlaki MD, Loureiro S. Unveiling the molecular mechanisms and developmental consequences of mercury (Hg) toxicity in zebrafish embryo-larvae: A comprehensive approach. Neurotoxicol Teratol 2023; 100:107302. [PMID: 37739188 DOI: 10.1016/j.ntt.2023.107302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 09/24/2023]
Abstract
Mercury (Hg) is a global contaminant affecting aquatic ecosystems' health. Chronic exposure to Hg has shown that the normal development of zebrafish embryo-larvae is affected. However, the molecular mechanisms behind the toxicity of Hg on fish embryonic development are still poorly understood. This work aimed to investigate the effects of Hg exposure on zebrafish embryo-larvae using a combined approach at individual (mortality, embryo development and locomotor behavior) and biochemical (neurotoxicity and oxidative stress enzymatic activities and protein phosphatase expression) levels. The Fish Embryo Toxicity assay followed the Organization for Economic Cooperation and Development Guideline 236 and used a concentration range between 13 and 401 μg Hg/L. Lethal and developmental endpoints were examined at 24, 48, 72 and 96 hpf. Biochemical markers, including Acetylcholinesterase (AChE), Catalase (CAT), Glutathione Reductase (GR), and Glutathione-S-Transferase (GST) activities and, for the first time, the expression of the protein phosphatase 1 gamma (PP1γ) was assessed after 24, 48, 72 and 96 h of exposure to 10 and 100 μg Hg/L. The behavioral effects of a sublethal range of Hg (from 0.8 to 13 μg Hg/L) were assessed using an automated video tracking system at 120 hpf. Several developmental abnormalities on zebrafish embryos and larvae, including pericardial edema, spin and tail deformities and reduced rate of consumption of the yolk sac, were found after exposure to Hg (LC50 at 96 hpf of 139 μg Hg/L) with EC50 values for total malformations ranging from 22 to 264 μg Hg/L. After 96 hpf, no significant effects were observed in the CAT and GR activities. However, an increase in the GST activity in a concentration and time-dependent manner was found, denoting possible stress-related adaptation of zebrafish embryos to deleterious effects of Hg exposure. The AchE activity showed a response pattern in line with the behavioral responses. At the lowest concentration tested, no significant effects were found for the AChE activity, whereas a decrease in AChE activity was observed at 100 μg Hg/L, suggesting that exposure to Hg induced neurotoxic effects in zebrafish embryos which in turn may explain the lack of equilibrium found in this study (EC50 at 96 hpf of 83 μg Hg/L). Moreover, a decrease in the PP1γ expression was found after 96 h of exposure to 10 and 100 μg Hg/L. Thus, we suggest that Hg may be an inhibitor of PP1γ in zebrafish embryos-larvae and thus, along with the alterations in the enzymatic activity of GST, explain some of the developmental malformations observed, as well as the lack of equilibrium. Hence, in this study, we propose the use of PP1 expression, in combination with apical and biochemical endpoints, as a precursor for assessing Hg's toxic mechanism on embryonic development.
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Affiliation(s)
- Magda Carvalho Henriques
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal; CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Inês Carvalho
- Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Cátia Santos
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Maria Teresa Herdeiro
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Margarida Fardilha
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Maria Dimitriou Pavlaki
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal.
| | - Susana Loureiro
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
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