Impacts of oxidative stress on acetylcholinesterase transcription, and activity in embryos of zebrafish (Danio rerio) following Chlorpyrifos exposure (original) (raw)
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Antioxidant Responses and NRF2 in Synergistic Developmental Toxicity of PAHs in Zebrafish
Toxicological Sciences, 2009
Early piscine life stages are sensitive to polycyclic aromatic hydrocarbon (PAH) exposure, which can cause pericardial effusion and craniofacial malformations. We previously reported that certain combinations of PAHs cause synergistic developmental toxicity, as observed with coexposure to the aryl hydrocarbon receptor agonist b-naphthoflavone (BNF) and cytochrome P4501A inhibitor a-naphthoflavone (ANF). Herein, we hypothesized that oxidative stress is a component of this toxicity. We examined induction of antioxidant genes in zebrafish embryos (Danio rerio) exposed to BNF or ANF individually, a BNF 1 ANF combination, and a prooxidant positive control, tert-butylhydroperoxide (tBOOH). We measured total glutathione (GSH) and attempted to modulate deformities using the GSH synthesis inhibitor L-buthionine (S,R)-sulfoximine (BSO) and increase GSH pools with N-acetyl cysteine (NAC). In addition, we used a morpholino to knockdown expression of the antioxidant response element transcription factor NRF2 to determine if this would alter gene expression or increase deformity severity. BNF 1 ANF coexposure significantly increased expressions of superoxide dismutase 1 and 2, glutathione peroxidase 1, pi class glutathione-s-transferase, and glutamate cysteine-ligase to a greater extent than tBOOH, BNF, or ANF alone. BSO pretreatment decreased some GSH levels, but did not worsen deformities, nor did NAC diminish toxicity. Knockdown of NRF2 increased mortality following tBOOH challenge, prevented significant upregulation of antioxidant genes following both tBOOH and BNF 1 ANF exposures, and exacerbated BNF 1 ANF-related deformities. Collectively, these findings demonstrate that antioxidant responses are a component of PAH synergistic developmental toxicity and that NRF2 is protective against prooxidant and PAH challenges during development.
Aquatic Toxicology, 2006
Exposure to dioxin-like chemicals that activate the aryl hydrocarbon receptor (AHR) can result in increased cellular and tissue production of reactive oxygen species (ROS). Little is known of these effects during early fish development. We used the fish model, Fundulus heteroclitus, to determine if the AHR ligand and pro-oxidant 3,3 ,4,4 ,5-pentachlorobiphenyl (PCB126) can increase ROS production during killifish development, and to test a novel method for measuring ROS non-invasively in a living organism. The superoxide-sensitive fluorescent dye, dihydroethidium (DHE), was used to detect in ovo ROS production microscopically in developing killifish exposed to PCB126 or vehicle. Both in ovo CYP1A activity (ethoxyresorufin-o-deethylase, EROD) and in ovo ROS were induced by PCB126. In ovo CYP1A activity was inducible by PCB126 concentrations as low as 0.003 nM, with maximal induction occurring at 0.3 nM PCB126. These PCB126 concentrations also significantly increased in ovo ROS production in embryonic liver, ROS being detectable as early as 5 days post-fertilization. These data demonstrate that the pro-oxidant and CYP1A inducer, PCB126, increases both CYP1A activity and ROS production in developing killifish embryos. The superoxide detection assay (SoDA) described in this paper provides a semi-quantitative, easily measured, early indicator of altered ROS production that can be used in conjunction with simultaneous in ovo measurements of CYP1A activity and embryo development to explore functional relationships among biochemical, physiological and developmental responses to AHR ligands.
PLoS ONE, 2014
Oxidative stress is an important mechanism of chemical toxicity, contributing to teratogenesis and to cardiovascular and neurodegenerative diseases. Developing animals may be especially sensitive to chemicals causing oxidative stress. The developmental expression and inducibility of anti-oxidant defenses through activation of NF-E2-related factor 2 (NRF2) affect susceptibility to oxidants, but the embryonic response to oxidants is not well understood. To assess the response to chemically mediated oxidative stress and how it may vary during development, zebrafish embryos, eleutheroembryos, or larvae at 1, 2, 3, 4, 5, and 6 days post fertilization (dpf) were exposed to DMSO (0.1%), tert-butylhydroquinone (tBHQ; 10 mM) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 2 nM) for 6 hr. Transcript abundance was assessed by real-time qRT-PCR and microarray. qRT-PCR showed strong (4-to 5-fold) induction of gstp1 by tBHQ as early as 1 dpf. tBHQ also induced gclc (2 dpf), but not sod1, nqo1, or cyp1a. TCDD induced cyp1a but none of the other genes. Microarray analysis showed that 1477 probes were significantly different among the DMSO-, tBHQ-, and TCDD-treated eleutheroembryos at 4 dpf. There was substantial overlap between genes induced in developing zebrafish and a set of marker genes induced by oxidative stress in mammals. Genes induced by tBHQ in 4-dpf zebrafish included those involved in glutathione synthesis and utilization, signal transduction, and DNA damage/stress response. The strong induction of hsp70 determined by microarray was confirmed by qRT-PCR and by use of transgenic zebrafish expressing enhanced green fluorescent protein (EGFP) under control of the hsp70 promoter. Genes strongly down-regulated by tBHQ included mitfa, providing a molecular explanation for the loss of pigmentation in tBHQ-exposed embryos. These data show that zebrafish embryos are responsive to oxidative stress as early as 1 dpf, that responsiveness varies with development in a gene-specific manner, and that the oxidative stress response is substantially conserved in vertebrate animals.
Aquatic Toxicology, 2009
Amphibian embryos are naturally exposed to prooxidant conditions throughout their development. Environmental exposure to contaminants may affect their capacity to respond to challenging conditions, to progress in a normal ontogenesis, and finally to survive and succeed in completing metamorphosis. We studied the effects of the exposure to two anticholinesterase agents, the carbamate carbaryl and the organophosphate azinphos methyl, on the antioxidant defenses of developing embryos of the toad Rhinella (Bufo) arenarum. Reduced glutathione (GSH) levels were increased early by carbaryl, but were decreased by both pesticides at the end of embryonic development. The GSH-dependent enzymes glutathione reductase and glutathione peroxidases showed oscillating activity patterns that could be attributed to an induction of activity in response to oxidative stress and inactivation by excess of reactive oxygen species. Glutathione-S-transferases, which may participate in the conjugation of lipid peroxide products in addition to pesticide detoxification, showed an increase of activity at the beginning and at the end of development. Catalase also showed variations in the activity suggesting, successively, induction and inactivation in response to pesticide exposure-induced oxidative stress. Superoxide dismutase activity was increased by carbaryl and transiently decreased by azinphos methyl exposure. Judging from the depletion in GSH levels and glutathione reductase inhibition at the end of embryonic development, the oxidative stress caused by azinphos methyl seemed to be greater than that caused by carbaryl, which might be in turn related with a higher number of developmental alterations caused by the organophosphate. GSH content is a good biomarker of oxidative stress in the developing embryos exposed to pesticides. The antioxidant enzymes are in turn revealing the balance between their protective capacity and the oxidative damage to the enzyme molecules, decreasing their activity.
Bulletin of Environmental Contamination and Toxicology, 2021
Benzophenone-3 (BP-3) is one of the most used UV lters. This study aimed to evaluate the toxic effects of BP-3 during embryo stages of zebra sh, four hours post-fertilization (4hpf). Embryos were exposed to 0, 1, and 10 µg L-1 of BP-3, for 72 hours. We investigated biochemical and molecular biomarkers of neurotoxicity (AChE) and the antioxidant system (gene expression of catalase, CAT, superoxide dismutase, SOD, glutathione peroxidase, GPX, the concentration of total glutathione, GSH, and lipid hydroperoxides, LPO). Results indicated that the acute exposure to BP-3 in zebra sh embryos did not show signi cant differences in survival, hatching rate, or in the biomarkers of antioxidant system. In contrast, there were signi cant differences associated with AChE gene expression and activity.
Relationship between oxidative stress and embryotoxicity of hydrosalpingeal fluid
Human Reproduction, 2002
BACKGROUND: Oxidative stress mechanisms are involved in the pathophysiology of many reproductive disorders. The objective of this study was to characterize oxidative stress parameters in hydrosalpingeal fluid (HSF) and examine their possible role in early embryo development. METHODS AND RESULTS: HSF was aspirated at laparoscopic salpingectomy in 11 infertile women. Reactive oxygen species (ROS), total (non-enzymatic) antioxidant capacity (TAC) and lipid peroxidation (LPO) were assayed. Two-cell mouse embryos were incubated with 25, 50 or 75% HSF and the blastocyst development rate was observed. ROS was detected in five of 11 (45%) HSF samples with a mean of 4.2⍥10 4 c.p.m. LPO was detected in all samples at a mean (⍨SD) value of 5575.4 ⍨ 6091.9 µmol/l malonaldehyde. The mean blastocyst development rate at 25, 50 and 75% HSF and in the control group was 88.9 ⍨ 9.4, 65.7 ⍨ 19.1, 45.7 ⍨ 5.7 and 96.7% respectively (P < 0.0001). The blastocyst development rate was positively correlated to ROS concentrations (P < 0.02) but was not significantly related to LPO. CONCLUSIONS: The blastocyst development rate decreased with increasing concentrations of HSF. For the first time, the presence of ROS, LPO and TAC activity in human HSF was characterized. A possible role of oxidative stress in the embryotoxicity of HSF is suggested.
Mechanisms for the Induction of Oxidative Stress in Syrian Hamster Embryo Cells by Acrylonitrile
Toxicological Sciences, 2002
Chronic administration of acrylonitrile to rats resulted in an increase in the incidence of glial neoplasms of the brain. Recent studies have shown that acrylonitrile induces oxidative stress in rat brain and cultured rat glial cells. Acrylonitrile also induces morphological transformation concomitant with an increase in the formation of oxidized DNA in Syrian Hamster Embryo (SHE) cells in a dose-dependent manner. The mechanism for the induction of oxidative stress in SHE cells remains unresolved. The present study examined the effects of acrylonitrile on enzymatic and nonenzymatic antioxidants in SHE cells. SHE cells were treated with subcytolethal doses of acrylonitrile (0, 25, 50, and 75 g/ml) for 4, 24, and 48 h. Acrylonitrile (50 g/ml and 75g/ml) increased the amount of reactive oxygen species in SHE cells at all time points. Glutathione (GSH) was depleted and catalase and superoxide dismutase activities were significantly decreased in SHE cells after 4 h of treatment. The inhibition of these antioxidants was temporal, returning to control values or higher after 24 and 48 h. Xanthine oxidase activity was increased following 24 and 48 h treatment with acrylonitrile. 1-aminobenzotriazole, a suicidal P450 enzyme inhibitor, attenuated the effects of acrylonitrile on catalase and xanthine oxidase in SHE cells, suggesting that P450 metabolism is required for acrylonitrile to produce its effects on these enzymes. Additional studies showed that in the absence of metabolic sources acrylonitrile had no effect on either catalase or superoxide dismutase activity. These results suggest that the induction of oxidative stress by acrylonitrile involves a temporal decrease in antioxidants and increase in xanthine oxidase activity that is mediated by oxidative metabolism of acrylonitrile.
The acrylamide effect studied on antioxidants and histoarchitecture of 11th day old developing chick embryo liver and cerebral cortex that was exposed to 0.2 to 0.6mg concentrations at 72h incubation showed maximum superoxide dismutase and glutathione-S-transferase activities up to 0.4mg acrylamide treatment than control activity. These tissues catalase and glutathione peroxidase also showed a decrease in activity to minimum when embryo was administered with 0.6mg acrylamide than control. The decreased activities might be related to oxidative damage that occurs variably in these two tissues. The histological sections of tissues on microscopic analysis have showed mild degeneration, vacuole formation, necrosis and total damage in liver, and mild degeneration in cortex was found at 0.6mg acrylamide treatment. So our experimental results conclude that acryalmide was capable of producing major alterations in liver than in cerebral cortex of chick embryo at 72h incubation doses of 0.6mg acrylamide.
The mechanisms of disorders in cell functions induced by 1,4-naphthoquinone amide derivatives are not clarified yet. The article is dedicated to the study of features of these substances influence on loach misgurnus fossilis L. embryos pro/antioxidant homeostasis during early embryogenesis. The aim of this work was to study the effect of 2-chloro-3-hydroxy-1,4-naphthoquinone, 2-chloro-3-(3-oxo-3-(piperidine-1-yl)propylamine)-1,4-naphthoquinone (FO-1), 2-chloro-3-(3-(morpholine-4-yl)-3-oxopropylamine)-1,4naphthoquinone (FO-2 at concentrations of 10-3 , 10-5 , 10-7 m on the content of TBA-reactive substances (a byproduct of lipid peroxidation) and the activities of superoxide dismutase and catalase in loach embryos. It was established that 1,4-naphthoquinone amide derivatives and 2-chloro-3-hydroxy-1,4-naphthoquinone decreased the content of lipid peroxidation products in embryo cells in a dose-dependent manner. The investigated compounds cause an increase in superoxide dismutase and catalase activities compared with the control value. The results of the two-factor ANOVA test indicate that 2-chloro-3-hydroxy-1,4-naphthoquinone and 1,4-naphthoquinone amide derivatives (FO-1, FO-2) have predominant influence on the TBA-reactive substances content and superoxide dismutase activity. However, the time of loach embryos development has a more pronounced effect on catalase activity than the studied 1,4-naphthoquinone derivatives.
Oxidant-Antioxidant Status and c-myc Expression in BPAand DEHP-Exposed Zebrafish Embryos
European Journal of Biology, 2017
Di-(2-ethylhexyl)-phthalate (DEHP) is used in polyethylene terephthalate plastics and bisphenol-A (BPA) is used to make polycarbonate plastics. The health-concerning effects of DEHP and BPA indicate their potential toxic effects. The Wnt/βcatenin signaling pathway is necessary for embryonic development. The c-MYC proto-oncogene (MYC) has been identified as a Wnt/β-catenin target gene, and MYC is a transcription factor that regulates the expression of many gene products related to cell proliferation, growth, differentiation, and apoptosis. Activation and overexpression of the MYC gene has been reported in many human cancers and during tumorigenesis. The aim of this study was to investigate the relationship between oxidantantioxidant balance and c-myc in BPA-and DEHP-exposed zebrafish embryos. The real-time-polymerase chain reaction was used to determine c-myc expression. Lipid peroxidation (LPO), nitric oxide (NO) levels, and superoxide dismutase (SOD) and glutathione-S-transferase (GST) activities were determined in homogenates prepared from pooled embryo samples. Increased expression of c-myc and decreased GST activity were observed in the BPA and DEHP groups. NO levels increased and SOD activity decreased in the BPA group, whereas LPO increased in the DEHP group. Disruption of oxidant-antioxidant balance in DEHP-and BPA-exposed zebrafish embryos was associated with increased c-myc expression and may be an important mechanism for the toxic effects of these chemicals.