Oxidative Stress In Zebrafish Embryos Research Articles

Polystyrene microplastics enhance microcystin-LR-induced cardiovascular toxicity and oxidative stress in zebrafish embryos

The health risks associated with combined exposure to microplastics (MPs) and cyanobacteria toxins have gained increasing attention due to the large-scale prevalence of cyanobacterial blooms and accumulation of MPs in aquatic environments. Therefore, we explored the cardiovascular toxic effects of microcystin-LR (MC-LR, 1, 10, 100 μg/L) in the presence of 5 μm polystyrene microplastics (PS-MPs, 100 μg/L) and 80 nm polystyrene nanoplastics (PS-NPs, 100 μg/L) in zebrafish models. Embryos were exposed to certain PS-MPs and PS-NPs conditions in water between 3 h post-fertilization (hpf) and 168 hpf. Compared to MC-LR alone, a significant decrease in heart rate was observed as well as notable pericardial edema in the MC-LR + PS-MPs/NPs groups. At the same time, sinus venosus and bulbus arteriosus (SV-BA) distances were significantly increased. Furthermore, the addition of PS-MPs/NPs caused thrombosis in the caudal vein and more severe vascular damage in zebrafish larvae compared to MC-LR alone. Our findings revealed that combined exposure to PS-NPs and MC-LR could significantly decreased the expression of genes associated with cardiovascular development (myh6, nkx2.5, tnnt2a, and vegfaa), ATPase (atp1a3b, atp1b2b, atp2a1l, atp2b1a, and atp2b4), and the calcium channel (cacna1ab and ryr2a) compared to exposure to MC-LR alone. In addition, co-exposure with PS-MPs/NPs exacerbated the MC-LR-induced reactive oxygen species (ROS) production, as well as the ROS-stimulated apoptosis and heightened inflammation. We also discovered that astaxanthin (ASTA) treatment partially attenuated these cardiovascular toxic effects. Our findings confirm that exposure to MC-LR and PS-MPs/NPs affects cardiovascular development through calcium signaling interference and ROS-induced cardiovascular cell apoptosis. This study highlights the potential environmental risks of the co-existence of MC-LR and PS-MPs/NPs for fetal health, particularly cardiovascular development.

Minocycline attenuates the bilirubin-induced developmental neurotoxicity through the regulation of innate immunity and oxidative stress in zebrafish embryos

When liver or intestinal function is impaired, bilirubin accumulates in the body and leads to neonatal jaundice. However, the potential negative effects caused by excessive accumulation of bilirubin such as developmental immunotoxicity and neurotoxicity remain unclear. We used a zebrafish model to establish bilirubin-induced jaundice symptoms and evaluated the toxic effects of bilirubin in aquatic organisms. Firstly, our results suggested that bilirubin exposure markedly decreased the survival rate, induced the developmental toxicity and increased the yellow pigment deposited in the zebrafish tail. Meanwhile, the number of macrophages and neutrophils was substantially reduced in a concentration-dependent manner. Besides, the antioxidant enzyme activities were greatly elevated while the inflammatory genes were significantly decreased after bilirubin exposure. Secondly, transcriptome analysis identified 708 genes were differentially expressed after bilirubin exposure, which animal organ morphogenesis, chemical synaptic transmission, and MAPK / mTOR signaling pathways were significantly enriched. Thirdly, bilirubin exposure leads to a significant decrease in the motility of zebrafish, including a dose-dependent decrease in the travelled distance, movement time, and average velocity. Moreover, the innate immune genes and apoptosis-related genes such as TLR4, NF-κB p65, STAT3 and p53 were elevated at a concentration of 10 μg/mL of bilirubin. Finally, our results further revealed that the anti-inflammatory and neuroprotective minocycline could partially rescue the bilirubin-induced neurobehavioral disorders in zebrafish embryos. In conclusion, our study explored the bilirubin-induced immunotoxicity and neurotoxicity in aquatic organisms, which will provide a theoretical basis for the treatment of neonatal jaundice in clinical practice.

Toxicity of o-phenylphenol on craniofacial cartilage development through ROS-induced oxidative stress in zebrafish embryos

O-phenylphenol (OPP), a commonly used antiseptic and bactericide, has some threat to human health and the environment. Environmental exposure to OPP may cause potential health hazards in animals and humans, and the developmental toxicity of OPP needs to be assessed. Therefore, the zebrafish model was used to evaluate the ecological impact of OPP, and the zebrafish craniofacial skeleton is mainly derived from the cranial neural crest stem cells (NCCs). In this study, zebrafish were exposed to 1,2,4 mg/L OPP from10 to 80 h post-fertilization (hpf). Our study observed that OPP could cause the early disorder of craniofacial pharyngeal arch development and lead to behavioural abnormalities. In addition, qPCR and enzyme activity revealed that OPP exposure would induce the production of reactive oxygen species (ROS) and oxidative stress. And proliferation cell nuclear antigen (PCNA) indicated that the proliferation of NCCs was reduced. The mRNA expression of genes related to migration, proliferation, and differentiation of NCCs has changed significantly under OPP exposure. Astaxanthin (AST), a widely used antioxidant, could partially rescue the craniofacial cartilage development exposed to OPP. The results showed improvements in oxidative stress, gene transcription, NCCs proliferation, and protein expression in zebrafish, suggesting that OPP may reduce antioxidant capacity and subsequently inhibit migration, proliferation, and differentiation of the NCCs. In conclusion, our study found that OPP may produce reactive oxygen species, leading to developmental toxicity in zebrafish craniofacial cartilage.

Design of a new self-assembling antioxidant nanomedicine to ameliorate oxidative stress in zebrafish embryos.

Oxidative stress, which is a persistent state of elevated reactive oxygen species (ROS), is implicated in the pathogeneses of several diseases, making antioxidant-based therapeutics the aptest intervention. Nevertheless, the clinical failure of conventional low-molecular-weight (LMW) antioxidants in oxidative stress-related diseases to yield favorable therapeutic outcomes and an increased mortality rate attributable to their poor pharmacokinetic characteristics, necessitates the development of alternative therapeutics. In light of this, we designed and synthesized a new amphiphilic polymer functionalized with a clinically safe base polymer of poly(styrene-co-maleic anhydride) copolymer conjugated with the LMW pleiotropic antioxidant TEMPO (a potent antioxidant) and biocompatible poly(ethylene glycol) (TEMPO-installed PSMA-g-PEG), which self-assembles into nano-sized micelles (SMAPoTN) under physiological conditions. We investigated its safety and antioxidant ability using zebrafish models. Common LMW antioxidants, such as 4-hydroxy-TEMPO (TEMPOL), vitamin C, N-acetyl-L-cysteine, and edaravone exposure induced phenotypic distortions, a manifestation of developmental toxicity, and resulted in high lethality in zebrafish larvae. LMW TEMPOL also adversely affected embryo hatchability, induced arrhythmia and cardiac edema, and failed to protect against oxidative stress. In contrast, exposure of zebrafish embryos to SMAPoTN increased the hatchability, protected embryos against various inducers of oxidative stress, and did not induce any phenotypic alterations or discernible toxicity. Taken together, we conclude that SMAPoTN surpasses LMW TEMPOL in terms of the ability to protect zebrafish, attributable to efficient ROS scavenging without perturbing normal redox homeostasis. These results imply that SMAPoTN can be used as a therapeutic intervention against various oxidative stress-induced diseases. STATEMENT OF SIGNIFICANCE: Failure of low molecular weight (LMW) antioxidants to improve therapeutic index in various oxidative stress-related pathogenesis, attributable to their poor pharmacokinetic characteristics, greatly limits their clinical translation. To overcome this limitation, we developed a self-assembling antioxidant nanoparticle (SMAPoTN) comprised of amphiphilic polymer; poly(styrene-co-maleic anhydride) conjugated with TEMPO as an antioxidant and biocompatible poly(ethylene glycol). Preliminary studies carried out in the in vivo models of zebrafish embryos confirmed that exposure of LMW antioxidant resulted in acute developmental toxicity, high lethality, and failure to rescue embryos against oxidative stress inducers. In contrast, SMAPoTN did not exert discernible toxicity and significantly improved their survival under oxidative stress. Our finding establishes antioxidant nanoparticles as more suitable therapeutic intervention for oxidative stress-induced diseases than LMW antioxidants.

Embryotoxicity and visual-motor response of functionalized nanostructured hydroxyapatite-based biomaterials in zebrafish (Danio rerio)

Hydroxyapatite (HA) is a biomaterial widely used in biomedical applications. Many studies have shown that ionic substituents can be incorporated into HA to produce a mineral composition more similar to natural bone tissue with more favorable biological characteristics for application in bone regeneration. However, its potentially toxic effects need to be evaluated before full approval for human use. For this purpose, an embryotoxicity test was performed on zebrafish according to OECD guideline 236. Zebrafish embryos were exposed to 1 or 3 microspheres of alginate containing nanoparticles of HA and carbonate (CHA), strontium (SrHA), and zinc-substituted HA (ZnHA) from 4 to 120 h post-fertilization (hpf). Lethality and developmental endpoints were evaluated. In addition, larval behavior at 168 hpf was also analyzed to observe whether biomaterials adversely affect optomotor and avoidance responses (neurotoxicity), as well as the oxidative stress pattern through qPCR. After 120 h exposure to all microspheres with different patterns of crystallinity, porosity, nanoparticle size, surface area, and degradation behavior, there was no mortality rate greater than 20%, indicating the non-embryotoxic character of these biomaterials. All experimental groups showed positive optomotor and avoidance responses, which means that embryo exposure to the tested biomaterials had no neurotoxic effects. Furthermore, larvae exposed to one SrHA microsphere showed a better optomotor response than the control. Furthermore, the biomaterials did not change the pattern of mRNA levels of genes related to oxidative stress even after 120 hpf. The growing number of new HA-based biomaterials produced should be accompanied by increased studies to understand the biosafety of these compounds, especially in alternative models, such as zebrafish embryos. These results reinforce our hypothesis that ion-substituted HA biomaterials do not impose toxicological effects, cause development and neuromotor impairment, or increase oxidative stress in zebrafish embryos being useful for medical devices and in the process of bone regeneration.

Chlorphoxim induces neurotoxicity in zebrafish embryo through activation of oxidative stress.

It is known that chlorphoxim is a broad-spectrum and high-effective pesticide. With the wide use in agricultural practice, chlorphoxim residue is also frequently detected in water, but its potential toxicity to aquatic life is still unclear. In this study, zebrafish is used as a model to detect the toxicity of chlorphoxim. Our results showed that exposure of high concentration of chlorphoxim at 96 h post-fertilization (hpf) resulted in a high mortality and pericardium edema rate, a low hatchability rate and heart rate. The nervous system damage, swimming behavior alteration and acetylcholinesterase (AChE) inhibition were measured in zebrafish embryos after a 6 days post-fertilization (dpf) of chlorphoxim exposure. The expression of neural-related genes is abnormal in zebrafish embryos. Chlorphoxim exposure significantly increases oxidative stress in zebrafish embryos by inhibiting antioxidant enzyme (SOD and CAT) and activating reactive oxygen species (ROS). As expected, chlorphoxim exposure induces apoptosis by enhancing the expression of apoptotic genes (Bax, Bcl2, and p53). Astaxanthin (ATX), an effective antioxidant, was found to be able to rescue the neurotoxicity of chlorphoxim through relieving oxidative stress and apoptosis. Altogether, the results showed that chlorphoxim exposure led to severe neurotoxicity to zebrafish embryos, which was contributed to a more comprehensive understanding of the safety use of the organophosphorus pesticide.

ZIF-8 nanoparticles induce neurobehavioral disorders through the regulation of ROS-mediated oxidative stress in zebrafish embryos

Zeolite imidazolate framework-8 (ZIF-8) is a nanomaterial of metal-organic frameworks (MOFs), which have various applications in drug delivery and water pollution remediation. However, little is known about its developmental neurotoxicity in aquatic organisms, especially on the low-level exposure. In the present study, we investigated the toxic effects of ZIF-8 NPs on the neuron development, behavioral traits, oxidative stress and gene expression in zebrafish embryos. Firstly, our results showed that ZIF-8 induced significantly embryonic malformations and abnormal development of nervous system in zebrafish embryos with a concentration-dependent manner. Meanwhile, the locomotor behavior was obviously inhibited while the anxiety behavior was greatly increased after ZIF-8 exposure. Secondly, the levels of ROS and antioxidant enzyme activities (CAT, SOD and MDA) together with AChE and ATPase were substantially increased in the ZIF-8 exposed groups. At the molecular level, ZIF-8 NPs could down-regulate the expression profiles of neural development-related genes (gap43, synapsin 2a and neurogenin 1) and PD-like related genes (dj-1, dynactin and parkin), but up-regulate the expression levels of neuro-inflammatory genes (nox-1, glip1a and glip1b) in larval zebrafish. In addition, we further explored the molecular mechanism of neurotoxicity induced by ZIF-8 with pharmacological experiments. The results showed that specific inhibition of ROS-mediated oxidative stress by the astaxanthin could reverse the expression patterns of ATPase, AChE and neurodevelopmental genes. Moreover, astaxanthin can partially rescue the ZIF-8-modulated locomotor behavior. Taken together, our results demonstrated that ZIF-8 had the potential to cause neurotoxicity in zebrafish embryos. These informations presented in this study will help to elucidate the molecular mechanisms of ZIF-8 nanoparticles exposure in zebrafish, which providing a scientific evaluation of its safety to aquatic ecosystems.

Hydoxylated β- and δ-Hexacholorocyclohexane metabolites infer influential intrinsic atomic pathways interaction to elicit oxidative stress-induced apoptosis for bio-toxicity

Hexachlorocyclohexane (HCH) has been recognized as an effective insecticide to protect crops against grasshoppers, cohort insects, rice insects, wireworms, and other agricultural pests and; for the control of vector-borne diseases such as malaria. It is a cyclic, saturated hydrocarbon, which primarily exists as five different stable isomers in the environment. Though the use of HCH is banned in most countries owing to its adverse effects on the environment, its metabolites still exist in soil and groundwater, because of its indiscriminate applications. In this study, a dose-dependent toxicity assay of the HCH isomers isolated from soil and water samples of different regions of Odisha, India was performed to assess the in vivo developmental effects and oxidative stress in zebrafish embryos. Toxicity analysis revealed a significant reduction in hatching and survivability rate along with morphological deformities (edema, tail malformations, spinal curvature) upon an increase in the concentration of HCH isomers; beta isomer exhibiting maximum toxicity (p < 0.05). Oxidative stress assay showed that ROS and apoptosis were highest in the fish exposed to β-2 and δ-2 isomers of HCH in comparison to the untreated one. Zebrafish proved to be a useful biological model to assess the biological effects of HCH isomers. In addition, the results suggest the implementation of precautionary measures to control the use of organochlorine compounds that can lead to a decrease in the HCH isomers in the field for a healthier environment.

Combined exposure to nanoplastics and metal oxide nanoparticles inhibits efflux pumps and causes oxidative stress in zebrafish embryos

The ubiquity of microplastic/nanoplastics (MP/NPs) provides an opportunity for their interaction with other widely spread environmental contaminants. MP/NP and nanoparticles share a similar transport route from sources, production, and disposal. Metal oxide nanoparticles (nMOx) have varied industrial applications, and limited knowledge is available on their interaction with MP/NPs. The present study investigated the effect of NPs (1 mg/L) on the efflux of two nMOx, aluminium oxide nanoparticles (nAl2O3, 1 mg/L) and cerium oxide nanoparticles (nCeO2, 1 mg/L), and their combined toxicity to zebrafish embryos. The results illustrated increased accumulation of aluminium and cerium in the combined exposure group compared to the nMOx alone treatment. The presence of NPs exacerbated the oxidative stress caused by nAl2O3 and nCeO2, as evidenced by an increase in the concentration of reactive oxygen species (ROS), alteration of antioxidants, and lipid peroxidation. The integrated biomarker response (IBRv2) values showed the induction of an antioxidative response in NP + nAl2O3, whereas a decline in IBRv2 values was observed in NP + nCeO2. Our results indicate that NPs aggravated the accumulation of nMOx and their toxicity. The present work highlights that more attention should be paid to the discharge of these contaminants into the natural environment.

Exposure to N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) affects the growth and development of zebrafish embryos/larvae

N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) is used as a ubiquitous rubber antioxidant worldwide and has been shown to be potentially toxic to aquatic organisms. In this study, zebrafish embryos were exposed to 6PPD for five days starting at two hours post-fertilization at concentrations of 0, 0.0022, 0.022, and 0.22 mg/L to investigate its effects on embryonic development, the growth hormone/insulin-like growth factor (GH/IGF) axis, and the hypothalamic-pituitary-thyroid (HPT) axis. The results showed that the 96 h LC50 of 6PPD was 2.2 mg/L. 6PPD exposure decreased hatchability, lowered autonomous movement, reduced body length in zebrafish embryos and caused deformities. The hormones levels and the expression of genes related to GH/IGF and HPT axis were altered after exposure to 6PPD in zebrafish larvae. These results indicated that the GH/IGF and HPT axis was disturbed. Moreover, treatment of 6PPD produced oxidative stress in zebrafish embryos. Overall, the present study thus demonstrated that exposure to 0.22 mg/L 6PPD caused developmental toxicity and disrupted the GH/IGF and HPT axis of zebrafish, which could be responsible for developmental impairment and growth inhibition.

Acute exposure to environmentally relevant concentrations of phenytoin damages early development and induces oxidative stress in zebrafish embryos

Phenytoin (PHE) is an antiepileptic drug that has been widely used in clinical practice for about 80 years. It is mainly used in the treatment of tonic-clonic and partial seizures. The widespread consumption of this drug around the world has led to PHE being introduced into water bodies through municipal, hospital, and industrial effluent discharges. Since the toxic effects of this drug on aquatic species has been scarcely explored, the aim of this work was to investigate the influence of low (25–400 ngL−1) and high (500–1500 ngL−1) environmentally relevant concentrations of PHE on the development and oxidative status of zebrafish (Danio rerio) embryos. The toxicity of PHE was evaluated from 12 to 96 h after fertilization in D. rerio at concentrations between 25 and 1500 ngL−1. In both the control group and the 0.05% DMSO system, no malformations were observed, all embryos developed normally after 96 h. The severity and frequency of malformations increased with increasing PHE concentration compared to embryos in the control group. Malformations observed included developmental delay, hypopigmentation, miscellaneous (more than one malformation in the same embryo), modified chorda structure, tail malformation, and yolk deformation. Concerning the biomarkers of oxidative stress, an increase in the degree of lipid peroxidation, protein carbonylation, and hydroperoxide content was observed (p < 0.05) concerning the control. In addition, a significant increase (p < 0.05) in antioxidant enzymes (SOD, CAT, and GPx) was observed at low exposure concentrations (25–400 ngL−1), with a decrease in enzyme activity at high concentrations (500–1500 ngL−1). Our IBR analysis demonstrated that oxidative damage biomarkers got more influence at 500ngL−1 of PHE. The results demonstrated that PHE may affect the embryonic development of zebrafish and that oxidative stress may be involved in the generation of this embryotoxic process.

Toxicity of O-Phenylphenol on Craniofacial Cartilage Development Through Ros-Induced Oxidative Stress in Zebrafish Embryos

Toxicity of O-Phenylphenol on Craniofacial Cartilage Development Through Ros-Induced Oxidative Stress in Zebrafish Embryos

Ethoprophos induces cardiac toxicity in zebrafish embryos

Ethoprophos is an effective and widely pesticide that used in controlling nemathelminth and soil insect. However, ethoprophos has been frequently detected in environment and freshwater. The potential toxicity to aquatic organisms is still not be explored. In this study, zebrafish embryo model was used to evaluated the toxicity of ethoprophos during cardiovascular developmental process of zebrafish. Zebrafish embryos were separately exposed to 10 mg/L, 20 mg/L, 30 mg/L, 40 mg/L and 50 mg/L of ethoprophos exposure at 96 h post-fertilization (hpf), which induced cardiac defects, such as low heart rate, pericardium edema and long SV-BA distance, but had no influence to vascular development. Mechanistically, the expression of cardiac-related genes were abnormal. Moreover, ethoprophos exposure significantly increased oxidative stress in zebrafish embryos by inhibiting the production of antioxidant enzyme (SOD) and activating reactive oxygen species. Expectedly, some apoptosis genes were induced and the apoptotic cardiomyocytes were detected by acridine orange staining. In addition, ethoprophos exposure also inhibited the expression of genes in wnt signaling pathway, such as β-catenin, Axin2, GSK3β and Sox9b. BML284, an activator of wnt signaling pathway, can rescue the cardiotoxic effect of embryos. These results indicated that oxidative stress and blocking wnt signaling pathway were molecular basis of ethoprophos-induced injure in zebrafish. Generally, our study showed that ethoprophos exposure led to severe cardiotoxicity to zebrafish embryo.

Oxidative stress as a potential mechanism by which guanylurea disrupts the embryogenesis of Danio rerio

Metformin is one the most prescribed drug to treat type 2 diabetes. In wastewater treatment plants, this drug is bacterially transformed to guanylurea, which occurs at higher concentrations in the aquatic environments than its parent compound. Since there is a huge knowledge gap about the toxicity of this metabolite on aquatic organisms, we aimed to investigate the impact of guanylurea on the embryonic development and oxidative stress biomarkers of zebrafish (Danio rerio). For this effect, zebrafish embryos (4 h post fertilization) were exposed to 25, 50, 100, 200, 250, 25,000, 50,000, 75,000 μg/L guanylurea until 96 h post fertilization. Guanylurea led to a significant delay in the hatching process in all exposure groups. Furthermore, this transformation product affected the embryonic development of fish, inducing severe body alterations and consequently leading to their death. The most pronounced malformations were malformation of tail, scoliosis, pericardial edema, yolk deformation and craniofacial malformation. Concerning oxidative stress response, we demonstrated that guanylurea induced the antioxidant activity of superoxide dismutase, catalase, and glutathione peroxidase in zebrafish embryos. In addition, the levels of lipid peroxidation, protein carbonyl and hydroperoxide content were also increased in the embryos exposed to this transformation product. However, the integrated biomarker response (IBR) analysis carried out in this study demonstrated that oxidative damage biomarkers got more influence over the embryos than antioxidant enzymes. Thus, we can conclude that guanylurea induces oxidative stress in zebrafish embryos, and that this transformation product impair the normal development of this freshwater organism.

Bifenazate exposure induces cardiotoxicity in zebrafish embryos.

Bifenazate is a novel acaricide for selective foliar spraying and is widely used to control mites in agricultural production. However, its toxicity to aquatic organisms is unknown. Here, a zebrafish model was used to study bifenazate toxicity to aquatic organisms. Exposure to bifenazate was found to cause severe cardiotoxicity in zebrafish embryos, along with disorders in the gene expression related to heart development. Bifenazate also caused oxidative stress. Cardiotoxicity caused by bifenazate was partially rescued by astaxanthin (an antioxidant), accompanied by cardiac genes and oxidative stress-related indicators becoming normalized. Our results showed that exposure to bifenazate can significantly change the ATPase activity and gene expression levels of the calcium signaling pathway. These led to heart failure, in which the blood accumulated outside the heart without entering it, eventually leading to death. The results indicated that bifenazate exposure caused cardiotoxicity in zebrafish embryos through the induction of oxidative stress and inhibition of the calcium signaling pathway.

Embryotoxicity evaluation of atractylodin and β-eudesmol using the zebrafish model

Atractylodin and β-eudesmol are the major active ingredients of Atractylodes lancea (Thunb) DC. (AL). Both compounds exhibit various pharmacological activities, including anticancer activity against cholangiocarcinoma. Despite the widespread use of this plant in traditional medicine in China, Japan, Korea, and Thailand, studies of their toxicological profiles are limited. The present study aimed to evaluate the embryotoxicity of atractylodin and β-eudesmol using the zebrafish model. Zebrafish embryos were exposed to a series of concentrations (6.3, 12.5, 25, 50, and 100 μM) of each compound up to 72 h post-fertilization (hpf). The results showed that atractylodin and β-eudesmol induced mortality of zebrafish embryos with the 50% lethal concentration (LC50) of 36.8 and 53.0 μM, respectively. Both compounds also caused embryonic deformities, including pericardial edema, malformed head, yolk sac edema, and truncated body. Only β-eudesmol decreased the hatching rates, while atractylodin reduced the heart rates of the zebrafish embryos. Additionally, both compounds increased reactive oxygen species (ROS) production and altered the transcriptional expression levels of superoxide dismutase 1 (sod1), catalase (cat), and glutathione S-transferase pi 2 (gstp2) genes. In conclusion, atractylodin and β-eudesmol induce mortality, developmental toxicity, and oxidative stress in zebrafish embryos. These findings may imply similar toxicity of both compounds in humans.

Toxic Effects of Food Colorants Erythrosine and Tartrazine on Zebrafish Embryo Development

Erythrosine and tartrazine are common artificial food additives which have become a part of daily human consumption. Advised daily intake values for these agents are set strictly, however, the actual intake is much higher than the recommended ADI. A higher intake of erythrosine and tartrazine is shown to exhibit adverse effects in mammalian models, and is thus a matter of public health concern. In this study we have assessed and compared the dose-dependent effects of erythrosine and tartrazine on inducing oxidative stress in zebrafish embryos. We performed the superoxide dismutase (SOD) enzyme activity assay to test the effect of the two food colorants on reactive oxygen species (ROS) production. Erythrosine and tartrazine treated embryos showed significantly increased SOD activity in an enzyme assay. Additionally SOD mRNA transcripts in the treated embryos were found to be upregulated. Erythrosine and tartrazine treatment specifically altered SOD1 mRNA transcript levels while it had no effect on SOD2 mRNA, the other isoform found in zebrafish. Our study shows that erythrosine at a concentration of 0.05% is embryotoxic in a dose and time dependent manner. Tartrazine treated embryos exhibit similar toxicity at a concentration of 0.5%. Erythrosine treated zebrafish embryos hatch much slower when compared to tartrazine treated embryos and control embryos. While erythrosine affects the yolk utilization, tartrazine exhibits teratogenic effects on early zebrafish embryos. The mRNA expression as well as biochemical analysis indicates that exposure to food colorants induces cytoplasmic SOD transcription to combat the ROS toxicity in zebrafish embryos.

High-performance centrifugal partition chromatography (HPCPC) for efficient isolation of diphlorethohydroxycarmalol (DPHC) and screening of its antioxidant activity in a zebrafish model

Abstract High-performance centrifugal partition chromatography (HPCPC) can be used for the rapid isolation of biologically active metabolites from natural sources. The present study investigates the one-step isolation of diphlorethohydroxycarmalol (DPHC), an algal polyphenol, from the brown seaweed Ishige okamurae by HPCPC and its protective effect against 2,2’-azobis dihydrochloride (AAPH) induced oxidative stress in zebrafish embryos. HPCPC was found to be efficient and effective for the isolation of DPHC from Ishige okamurae under optimized solvent conditions, yielding a high purity product. The present purification method helps overcome compound wasting and possible degradation, which cause a low yield in conventional column separations. Further, zebrafish embryos exposed to AAPH were compared with and without DPHC treatment, two days after fertilization for ROS generation, cell death, lipid peroxidation, survival rate, and heartbeat rates. These evaluations revealed that DPHC treatment significantly enhanced protection against oxidative stress in zebrafish embryos. HPCPC was, therefore, established as an efficient DPHC isolation method and could be used for separating other complex phlorotannins from seaweeds.

Silver nanoparticles synthesized with a fraction from the bark of Eysenhardtia polystachya with high chalcone and dihydrochalcone content effectively inhibit oxidative stress in the zebrafish embryo model

Objective(s): In this study, we desvcribe a simple eco-friendly approach for the synthesis of a potent, stable and benign silver nanoparticles to carry and deliver chalcones and dihydrochalcones present in a methanol extract of Eysenhardtia polystachya (EP). Materials and Methods: In this process silver nanoparticles carring EP compounds (EP/AgNPs) are synthesized in a single step by eliminating the additional handling associated with incorporating EP compounds. The resulting nanoparticles (EP/AgNPs) were characterized using several physicochemical techniques. Cell viability was measured in vitro with RAW264.7 murine macrophage cells. In addition, we evaluated the ability of EP and EP/AgNPs to protect against glucose-induced oxidative in vivo stress using zebrafish embryos. Results: The synthesized EP/AgNPs showed an absorption peak at 413 nm on ultraviolet-visible spectroscopy (UV-vis), revealing the surface plasmon resonance of the nanoparticles. Transmission electron microscopy (TEM) indicated that most of the particles were spherical with a diameter of 10 to 12 nm, a polydispersity index (PDI) of 0.197 and a zeta potential of –32.25 mV, suggesting high stability of these nanoparticles. This study also demonstrated the biocompatibility of the nanoparticles when tested in RAW264.7 cells and its protective efficacy against oxidative stress induced by the exposure of zebrafish embryos to high glucose concentrations. Treatment with EP/AgNPs increased the activity of anti-stress biomarkers such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and total soluble protein. Exposure of the embryos to EP/AgNPs significantly (P<0.05) suppressed the formation of malondialdehyde (MDA) and lipid oxidation (LPO). Conclusion: EP/AgNPs synthesized from E. polystachya extract provide an effective defense against oxidative stress in zebrafish embryos.

Protective Effects of Xylose-Taurine Reduced against Damages Caused by Oxidative Stress in Zebrafish Embryos In Vivo Model.

The zebrafish (Danio rerio) is useful and convenient vertebrate models in various studies in human disease and drug discovery. In this present study, we first evaluated whether Xylose-Taurine reduced (X-T-R), a taurine derivate protects zebrafish embryos against oxidative stress caused by AAPH (2,2'-Azobis(2-amidinopropane) dihydrochloride). First of all, we selected the concentration of X-T-R showing no toxicity in zebrafish embryos. We identified that X-T-R significantly increased the survival of zebrafish embryo reduced by treatment of AAPH. Also, X-T-R effectively inhibited the productions of reactive oxygen species (ROS) and nitric oxide (NO) as well as the formation of cell death in zebrafish embryos. Moreover, X-T-R down-regulated the expression levels of Bax, caspase-3, caspase-9 and p53 known as pro-apoptotic molecules, whereas up-regulated those of Bcl-2, an anti-apoptotic molecule in AAPH-treated zebrafish embryos. From these results, this study reveals that X-T-R, a taurine derivate might be a potential protector against various damages caused by oxidative stress.