RESUMEN
Plasticizers are considered as newly emerged contaminants. They are added to plastics to increase their flexibility and softness. Phthalate plasticizers including the Di-2-ethylhexyl phthalates (DEHP) are toxic and induce adverse effects on the different organization levels of the environment. In the current study, we investigated the potential toxicity of DEHP using Zebrafish as a biological model. Five ascending concentrations of DEHP were tested in embryos throughout 96 hpf: 0.0086, 0.086, 0.86, 8.6, and 86 mg/L. Embryotoxicity assessments revealed limited lethal effects on DEHP-exposed embryos, yet notable anticipation of the hatching process was observed at 48 hpf. Although DEHP showed negligible influence on the length and pericardial area of exposed embryos, it led to multiple bodily deformities. Gene expression analyses of key cardiogenic and inflammatory genes evidenced alterations in tbx20, bcl2, and il1b expression in Zebrafish embryos at 96 h post-fertilization. Results from the cardiac function analysis displayed that DEHP significantly affected the arterial pulse and linear velocity within the Posterior Cardinal Vein (PCV) of exposed fish. These findings strongly advance that even at low concentrations, DEHP can be considered as potential toxic agent, capable of inducing cardiotoxic effects.
Asunto(s)
Dietilhexil Ftalato , Embrión no Mamífero , Plastificantes , Pez Cebra , Animales , Pez Cebra/embriología , Dietilhexil Ftalato/toxicidad , Embrión no Mamífero/efectos de los fármacos , Plastificantes/toxicidad , Cardiotoxicidad , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Corazón/efectos de los fármacos , Corazón/embriologíaRESUMEN
The sperm-specific phospholipase C zeta (PLCζ) protein is widely considered as the predominant physiological stimulus for initiating the Ca2+ release responsible for oocyte activation during mammalian fertilization. The increasing number of genetic and clinical reports that directly link PLCζ defects and/or deficiencies with oocyte activation failure (OAF) necessitates the use of a powerful therapeutic intervention to overcome such cases of male factor infertility. Currently, in vitro fertilization (IVF) clinics treat OAF cases after intracytoplasmic sperm injection (ICSI) with Ca2+ ionophores. Despite their successful use, such chemical agents are unable to trigger the physiological pattern of Ca2+ oscillations. Moreover, the safety of these ionophores is not yet fully established. We have previously demonstrated that recombinant PLCζ protein can be successfully used to rescue failed oocyte activation, resulting in efficient blastocyst formation. Herein, we produced a maltose binding protein (MBP)-tagged recombinant human PLCζ protein capable of inducing Ca2+ oscillations in mouse oocytes similar to those observed at fertilization. Circular dichroism (CD) experiments revealed a stable, well-folded protein with a high helical content. Moreover, the recombinant protein could retain its enzymatic properties for at least up to 90 days after storage at -80 °C. Finally, a chick embryo model was employed and revealed that exposure of fertilized chicken eggs to MBP-PLCζ did not alter the embryonic viability when compared to the control, giving a first indication of its safety. Our data support the potential use of the MBP-PLCζ recombinant protein as an effective therapeutic tool but further studies are required prior to its use in a clinical setting.
RESUMEN
Compared to classical techniques of morphological analysis, micro-CT (µ-CT) has become an effective approach allowing rapid screening of morphological changes. In the present work, we aimed to provide an optimized micro-CT dense agent perfusion protocol and µ-CT guidelines for different stages of chick embryo cardiogenesis. Our study was conducted over a period of 10 embryonic days (Hamburger-Hamilton HH36) in chick embryo hearts. During the perfusion of the micro-CT dense agent at different developmental stages (HH19, HH24, HH27, HH29, HH31, HH34, HH35, and HH36), we demonstrated that durations and volumes of the injected contrast agent gradually increased with the heart developmental stages contrary to the flow rate that was unchanged during the whole experiment. Analysis of the CT imaging confirmed the efficiency of the optimized parameters of the heart perfusion.
RESUMEN
Chemicals are at the top of public health concerns and metals have received much attention in terms of toxicological studies. Cadmium (Cd) and mercury (Hg) are among the most toxic heavy metals and are widely distributed in the environment. They are considered important factors involved in several organ disturbances. Heart and brain tissues are not among the first exposure sites to Cd and Hg but they are directly affected and may manifest intoxication reactions leading to death. Many cases of human intoxication with Cd and Hg showed that these metals have potential cardiotoxic and neurotoxic effects. Human exposure to heavy metals is through fish consumption which is considered as an excellent source of human nutrients. In the current review, we will summarize the most known cases of human intoxication with Cd and Hg, highlight their toxic effects on fish, and investigate the common signal pathways of both Cd and Hg to affect heart and brain tissues. Also, we will present the most common biomarkers used in the assessment of cardiotoxicity and neurotoxicity using Zebrafish model.
RESUMEN
Plasticizers are broadly classified as phthalate or nonphthalate. Recently, acetyl tributyl citrate (ATBC), an environmentally friendly nonphthalate plasticizer, was revealed to have the ability to disrupt thyroid hormone activity in fish species. Therefore, we aimed to assess whether ATBC exhibits any sex hormone (i.e., androgenic or estrogenic) activities. First, we examined the effects of ATBC on gonadal sex differentiation. Subsequently, we analyzed the different expression of biomarker genes that respond to endocrine-disrupting chemicals (EDCs) with sexual hormone activity in the liver. We observed normal testes and ovaries after both XX and XY medakas were exposed to ATBC, indicating that ATBC is not an EDCs with strong sex hormone activity and that it does not induce intersex (testis-to-ova or ovo-to-testis) or sex changes in Japanese medaka. The vitellogenin 1 (vtg1) and vitellogenin 2 (vtg2) mRNA expression levels in the liver of XX medakas were significantly reduced compared with those in the control group, whereas the expression levels of these genes in the liver of XY medakas remained unchanged. Finally, we examined the changes in the expression of biomarker genes that respond to EDCs with sex hormone activity in the gonads. The expression levels of biomarker genes did not differ significantly from that of the control group, although the expression levels of gsdf mRNA tended to increase while that of aromatase mRNA tended to decrease in the ovary of XX medakas following ATBC exposure. Conversely, the expression levels of gsdf and aromatase mRNAs in the testis of XY medakas remained unchanged. These results suggest that ATBC does not exhibit estrogenic activity, although it may have weak androgenic activity or no sexual hormone activity.
Asunto(s)
Oryzias , Contaminantes Químicos del Agua , Animales , Masculino , Femenino , Oryzias/genética , Oryzias/metabolismo , Aromatasa/metabolismo , Diferenciación Sexual , Vitelogeninas/genética , Vitelogeninas/metabolismo , Contaminantes Químicos del Agua/toxicidad , Gónadas/metabolismo , Plastificantes/metabolismo , Biomarcadores/metabolismo , Hormonas Esteroides Gonadales/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
Collectively known as congenital heart defects (CHDs), cardiac abnormalities at birth are the most common forms of neonatal defects. Being principally responsible for the heart's pumping power, ventricles are particularly affected by developmental abnormalities, such as flow disturbances or genomic defects. Hypoplastic Right Heart Syndrome (HRHS) is a rare disease where the right ventricle is underdeveloped. In this study, we introduce a surgical procedure performed on chick embryo, termed right atrial ligation (RAL) for disturbing hemodynamics within the right heart aiming in order to generate an animal model of HRHS. RAL is a new surgical manipulation, similar to the well-studied left atrial ligation (LAL) surgery but it induces the hemodynamic change into the right side of the heart. After inducing RAL, We utilized techniques such as Doppler ultrasound, x-ray micro-CT, histology, and computational fluid dynamics (CFD) analysis, for a comprehensive functional and structural analysis of a developing heart. Our results displayed that RAL does not induce severe flow disturbance and ventricular abnormalities consistent with clinical findings. This study allows us to better understand the hemodynamics-driven CHD development and sensitivities of ventricles under disturbed flows.
RESUMEN
Marine environments are affected by large amounts of toxicants among those mercury (Hg). The aim of this study was to assess potential neurotoxic effects of Hg in the peacock blenny Salaria pavo. A sublethal contamination to 66 µg HgCl2 L-1 over periods of 1, 4, 10 and 15 days was performed. Total Hg concentrations measured in the brain highlighted the detection of Hg at days 1 and 4 following the exposure but no concentration of the metal was further detected. Partial-length cDNA of genes coding ABC transporters (abcb1, abcc1, abcc2, abcg2) and acetylcholinesterase (ache) were characterized. Results from mRNA expression levels displayed an up-regulation of abcb1 mRNA while a down-regulation of abcc1 and abcc2 mRNA was observed. No change in abcg2 and ache mRNA expression was noted throughout the experiment. At each sampling time, Hg exposure did not affect the activity of the AChE enzyme. The histological analysis indicated that fish exhibited several damages in the optic tectum and the cerebellum and 3 reaction patterns were identified for each organ: circulatory disturbances, regressive and progressive changes. Molecular, physiological and histological biomarkers assessed in the present study highlighted that peacock blennies were able to detoxify Hg from the brain tissue by developing defense mechanisms. More globally, neurotoxic effects of a sublethal Hg exposure in the brain of peacock blennies and the adaptation capacity of this species were evaluated.
Asunto(s)
Encéfalo/efectos de los fármacos , Proteínas de Peces/metabolismo , Cloruro de Mercurio/química , Mercurio/química , Perciformes/metabolismo , Animales , Proteínas de Peces/genéticaRESUMEN
Cadmium (Cd) is considered as an important factor involved in several neurological disturbances. The aim of this study was to assess the effects of Cd in the brain of peacock blennies Salaria pavo, a species used as a bioindicator of water pollution. A sublethal contamination of 2mg CdCl2 L-1 was performed over periods of 1, 4, 10 and 15 days. Total Cd accumulation was measured in brains and displayed low concentrations throughout the experiment. Partial-length cDNA of different ATP-binding cassette transporters (abcb1, abcc1, abcc2, abcg2 proteins) and acetylcholinesterase (ache) were characterized. mRNA expressions profiles displayed an up-regulation of abcc2 mRNA after 4 days of Cd exposure only while abcg2 mRNA was down-regulated after 10 days only. For AChE, the mRNA transcription and the activity of the enzyme were followed and highlighted that Cd exerted an inhibitory effect on the nervous information transmission. At the histological level, fish exhibited pathological symptoms in the optic tectum and the cerebellum and results showed that the cerebellum was the most affected organ.
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Encéfalo/efectos de los fármacos , Cadmio/toxicidad , Síndromes de Neurotoxicidad , Perciformes/metabolismo , Contaminantes Químicos del Agua/toxicidad , Transportadoras de Casetes de Unión a ATP/genética , Acetilcolinesterasa/genética , Acetilcolinesterasa/metabolismo , Animales , Encéfalo/metabolismo , Encéfalo/patología , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Síndromes de Neurotoxicidad/genética , Síndromes de Neurotoxicidad/metabolismo , Síndromes de Neurotoxicidad/patología , Síndromes de Neurotoxicidad/veterinaria , ARN Mensajero/metabolismo , Regulación hacia ArribaRESUMEN
For humans, fish consumption is the major source of mercury (Hg) exposure. The aim of this study was to assess the effect of Hg in the peacock blenny Salaria pavo, a species of the family of blennies that was used as indicator of water pollution. We performed a sublethal contamination of fish to 66 µg HgCl2 L-1 during 1, 4, 10 and 15 days but Hg concentration measured in the experimental water was much lower than the nominal concentration. Hg was also measured in both gill and liver tissues and displays a significant increase of its concentration in gills after 1 day of exposure followed by a decrease throughout the experiment. In the liver, Hg burden reaches its maximum at day 4 followed also by a decrease. Partial-length cDNA of mt1, mt2, gpx, cat, mnsod and cuznsod was characterized. Results from mRNA expression levels displayed an up-regulation of mt1, gpx and mnsod while a downregulation of cat was observed. Several biomarker activities were determined in gills and liver and exposure to Hg affected all antioxidant enzymes in gills. EROD, GST and GPx significantly decreased, while CAT levels increased from 4 days of Hg exposure. No lipid peroxidation (LPO) induction was observed in gills of exposed fish. Regarding the liver, the activity of all enzymes increased significantly from the beginning of the experiment. LPO induction was, however, induced after 4 days only. The histological analysis also performed indicated that fish exhibited several damages in gills and liver, mainly in relation to circulatory disturbances in the gills and regressive changes in the liver. All biomarkers assessed showed that peacock blennies are able to detoxify Hg from gill and liver tissues by developing various defense mechanisms.
Asunto(s)
Cloruro de Mercurio/toxicidad , Mercurio/toxicidad , Perciformes/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Branquias/efectos de los fármacos , Branquias/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Cloruro de Mercurio/metabolismo , Mercurio/metabolismo , Distribución Tisular , Túnez , Contaminantes Químicos del Agua/metabolismoRESUMEN
Cadmium (Cd) is one of the most toxic metals and is widely distributed in freshwater and marine environments. It has received much attention from a toxicological perspective. The aim of this study was to assess the effect of Cd in the peacock blenny Salaria pavo, a species of the family of blennies that was used as bioindicator of water pollution. We performed a sublethal contamination of fish to 2 mg CdCl2 L(-1) during 1, 4, 10, and 15 days. Cd accumulation was measured in gills and liver and displayed a significant increase of its concentration throughout the experiment, with slightly higher levels in the liver, except after 4 days. Partial-length cDNA of mt1, mt2, mnsod, cuznsod, cat, and gpx were characterized. Results from mRNA expression levels displayed an up-regulation of mt2 and mnsod. Biomarker activities were determined in gills and liver. In gills, data displayed an inhibition of EROD and GST activities. Cd exposure significantly increased GPx activities but did not affect CAT levels throughout the experiment. No LPO induction was observed in gills of exposed fish. Regarding the liver, the activity of all enzymes and MDA levels increased significantly from the beginning of the experiment except EROD that increased after 15 days of contamination only. At the histological level, fish exhibited pathological symptoms in gills and liver with a predominance of circulatory disturbances in gills and regressive changes in the liver. Our results displayed that peacock blennies are able to survive Cd toxicity due to various physiological adaptation mechanisms.
Asunto(s)
Cadmio/toxicidad , Peces/fisiología , Contaminantes Químicos del Agua/toxicidad , Animales , Biomarcadores/metabolismo , Cadmio/metabolismo , Monitoreo del Ambiente , Peces/metabolismo , Agua Dulce , Branquias/metabolismo , Hígado/metabolismo , Perciformes/metabolismo , Superóxido Dismutasa/metabolismo , Regulación hacia Arriba , Contaminantes Químicos del Agua/metabolismoRESUMEN
Deltamethrin pesticide and copper have intensively been used in agriculture and industrial activities and can finally reach the marine ecosystem at high concentrations affecting the health of organisms. In this study, we assessed under laboratory conditions the toxic interactions between deltamethrin and copper and their effects on the fertility rate, cell mitotic division rate, and embryo developmental events of the sea urchin (Paracentrotus lividus). The exposure of sperm to increasing concentrations of deltamethrin (6.10(-5) and 6.10(-2) µg/L) and copper (50 and 100 µg/L) or to their mixture (6.10(-5) µg/L of deltamethrin and 50 µg/L of CuSO4) caused a significant alteration on the fertilizing capability of spermatozoids. Concentration-dependent toxic effects on the early cleavage in P. lividus were observed in groups treated with copper, deltamethrin, and their mixture. The kinetics of early divisions was accelerated and the average size of pluteus larvae was decreased under pollutant treatments. Several developmental anomalies were identified in pluteus, including crossed skeletal tips at the hood apex, joined or atrophied arms, and alteration of general larva shape. In conclusion, the sea urchin represents a suitable and sensitive model for testing the toxicity and the effects of deltamethrin pesticide and copper in sea water. In addition, the sensitivity of various end points to studied contaminants, proved their utility in the infield biomonitoring studies.