Possible involvement of Fas/FasL-dependent apoptotic pathway in α-bisabolol induced cardiotoxicity in zebrafish embryos

Paris saponin Ⅰ induce toxicity in zebrafish by up-regulation of p53 pathway and down-regulation of wnt pathway

Paris saponin I, II, and VII are three important components in Paris polyphylla, which have been widely studied as tumor cytotoxic drugs, but their safety in vivo has not been reported. Therefore, this study evaluated the safety of these three drugs based on the zebrafish model. Firstly, the lethality curves and half lethal rates of the three saponins were determined and the results showed the values of LC₅₀ of Paris saponin I, II, and VII were 122.2, 210.7, 566.2 ng/ml, respectively. And then our data revealed that Paris saponin I, II and VII had definite hepatotoxicity, as shown by their significant reduction in the liver area and fluorescence intensity of zebrafish. Besides, Paris saponin Ⅰ affected the heart rate of zebrafish obviously, suggesting its cardiovascular toxicity. Afterwards, we found Paris saponin Ⅰ and Ⅶ reduced the area and fluorescence intensity of kidney in zebrafish, and had mild nephrotoxicity. And when treated with Paris saponin I, the pathological section of liver tissue in zebrafish showed vacuoles, severe necrosis of hepatocytes, and then the apoptosis of hepatocytes could be observed by TUNEL staining. Eventually, we found that the genes expression of p53, Bax and β-catenin changed significantly in the administration group of Paris saponin I. In general, our study proved Paris saponin Ⅰ was the most toxic of the three saponins, and the most definite toxic target sites were liver and cardiovascular. And it was further inferred that the hepatotoxicity of Paris saponin Ⅰ may be related to the regulation of p53 pathway and Wnt pathway. These results above showed the toxicity of the three saponins in zebrafish, suggesting their safety should be paid more attention in the future.

Impact of pharmaceutical products on zebrafish: An effective tool to assess aquatic pollution

Overuse of pharmaceuticals products (PPs) and sometimes ineffective wastewater purification systems have led to the accumulation of these residues in aquatic systems. Raising concerns about the likely harmful effects of these substances both to ecosystems and to human health. Animals as model organisms are nowadays increasingly used to track the health of environmental system around the world. They can be used to understand biological processes, to obtain information on the health status of the environment, and to better understand the effects of xenobiotics on organisms. Among model organisms, the zebrafish (Danio rerio) is one of the best models for studying evolution biology, cancer, toxicology, drug discovery, and genetics. This fish is a multipurpose model organism, due to its easy of maintenance and keeping and the transparency of the embryo during the early stages of development. In this paper, the toxicological effects of typical PPs, and their effects on zebrafish are reviewed. Many PPs have been found to be toxic or even fatal to zebrafish. Showing how these pharmaceuticals compound can affect zebrafish from the larval stage and even in the adult stage. Zebrafish is thus a model for how we can better understand how medications affect not only individual fish but the entire aquatic ecosystem, bringing about perturbations in their behaviour and putting their survival at risk.

Evaluation of toxicity of Personal Care Products (PCPs) in freshwaters: Zebrafish as a model

Personal care products (PCPs) are part of the large and growing family of emerging contaminants (ECs). Many daily products such as sunscreens, toothpaste, make-up products, perfume, and others, fall under this definition, and their use is increasing exponentially. Furthermore, the degradation of some components of these products is limited. Indeed, they are able to easily reach and accumulate in aquatic systems, representing a new class of contaminants. Moreover, due to their chemical properties, they can interfere at different biological levels, and for this reason, they need to be thoroughly investigated. We have reviewed the literature on PCPs, with a special focus on the adverse effects on the freshwater zebrafish (Danio rerio). The aim of this work is to provide a careful assessment of the toxicity of these compounds, in order to raise awareness for more conscious and responsible use.

Cardiotoxicity of sanguinarine via regulating apoptosis and MAPK pathways in zebrafish and HL1 cardiomyocytes

Sanguinarine, a plant phytoalexin, possesses extensive biological activities including antimicrobial, insecticidal, antitumor, anti-inflammatory and anti-angiogenesis effect. But its cardiotoxicity has rarely been studied. Here, we assess the cardiotoxicity of sanguinarine in vivo using larval zebrafish from 48 hpf to 96 hpf. The results show that sanguinarine caused severe malformation and the dysfunction of the heart including reductions of heart rate, red blood cell number, blood flow dynamics, stroke volume and increase of SV-BA distance, subintestinal venous congestion. Further studies showed that apoptosis in the zebrafish heart region was observed after sanguinarine exposure using TUNEL assay and AO staining method. In addition, the genes, such as sox9b, myl7, nkx2.5 and bmp10, which play crucial parts in the development and the function of the heart, were changed after sanguinarine treatment. caspase3, caspase9, bax and bcl2, apoptosis-related genes, were also altered by sanguinarine. Further studies were performed to study the cardiotoxicity in vitro using cardiomyocytes HL1 cell line. The results showed that remarkable increase of apoptosis and ROS level in HL1 cells were induced by sanguinarine. Moreover, the MAPK pathway (JNK and P38) were notably enhanced and involved in the cardiotoxicity induced by sanguinarine. Our findings will provide better understanding of sanguinarine in the toxic effect on heart.

Progress in using zebrafish as a toxicological model for traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) has been applied for more than 2000 years. However, modern basic research on the safety of TCMs is limited. Establishing safety evaluation technology in line with the characteristics of TCM and conducting large-scale basic toxicity research are keys to comprehensively understand the toxicity of TCMs. In recent years, zebrafish has been used as a model organism for toxicity assessment and is increasingly utilized for toxicity research of TCMs. Yet, a comprehensive review in using zebrafish as a toxicological model for TCMs is lacked.

AIM OF THE STUDY

We aim to summarize the progress and limitation in toxicity evaluation of TCMs using zebrafish and put forward the future research ideas.

MATERIALS AND METHODS

The scientific databases, including Springer, Science Direct, Wiley, Pubmed and China Knowledge Resource Integrated (CNKI) were searched using the key words of zebrafish, toxicology, traditional Chinese medicine, acute toxicity, liver injury, cardiotoxicity, kidney toxicity, developmental toxicity, neurotoxicity, gastrointestinal irritation, immunotoxicity, ototoxicity, and osteotoxicity.

RESULTS

Zebrafish assays are low experimental cost and short cycle, easily achieving high-throughput toxicity screening, and exemption from ethical legislation up to 5 dpf. It has been widely used to evaluate the acute toxicity, liver toxicity, cardiotoxicity, nephrotoxicity, developmental toxicity, neurotoxicity, gastrointestinal irritation, immunotoxicity, and ototoxicity caused by TCMs, although some physiological difference limited its application.

CONCLUSIONS

Zebrafish is a powerful model for TCMs toxicity evaluation, but it is not flawless. The toxicity testing criterion and high throughput assays are urgent to be established. This review provides references for future studies.

Developmental toxicity caused by sanguinarine in zebrafish embryos via regulating oxidative stress, apoptosis and wnt pathways

Sanguinarine, derived from the root of Sanguinaria canadensis, have multiple biological activities, such as antimicrobial, insecticidal, antitumor, anti-inflammatory and anti-angiogenesis effect, but little is known about its toxicity on normal embryonic development. Here, we study the developmental toxicity using zebrafish model. Notably, sanguinarine caused a significant increase of the malformation rate and decrease of hatching rates and body length of zebrafish embryos. Sanguinarine also impaired the normal development of heart, liver and nerve system of zebrafish embryos. Further, the ROS level and MDA concentrations were remarkably increased, while the activity of T-SOD was decreased. In addition, obvious increase of apoptosis were observed by AO staining or TUNEL assay. Further studies showed that the oxidative stress-, apoptosis-related genes were changed, while genes of nrf2 and wnt pathways were inhibited by sangunarine. To sum up, our study will be helpful to understand the adverse effect of sanguinarine on embryonic development and the underlying molecular mechanism.

Protective Effect of Chlorogenic Acid and Its Analogues on Lead-Induced Developmental Neurotoxicity Through Modulating Oxidative Stress and Autophagy

Lead (Pb) is among the deleterious heavy metal and has caused global health concerns due to its tendency to cause a detrimental effect on the development of the central nervous system (CNS). Despite being a serious health concern, treatment of Pb poisoning is not yet available, reflecting the pressing need for compounds that can relieve Pb-induced toxicity, especially neurotoxicity. In the quest of exploring protective strategies against Pb-induced developmental neurotoxicity, compounds from natural resources have gained increased attention. Chlorogenic acid (CGA) and its analogues neochlorogenic acid (NCGA) and cryptochlorogenic acid (CCGA) are the important phenolic compounds widely distributed in plants. Herein, utilizing zebrafish as a model organism, we modeled Pb-induced developmental neurotoxicity and investigated the protective effect of CGA, NCGA, and CCGA co-treatment. In zebrafish, Pb exposure (1,000 μg/L) for 5 days causes developmental malformation, loss of dopaminergic (DA) neurons, and brain vasculature, as well as disrupted neuron differentiation in the CNS. Additionally, Pb-treated zebrafish exhibited abnormal locomotion. Notably, co-treatment with CGA (100 µM), NCGA (100 µM), and CCGA (50 µM) alleviated these developmental malformation and neurotoxicity induced by Pb. Further underlying mechanism investigation revealed that these dietary phenolic acid compounds may ameliorate Pb-induced oxidative stress and autophagy in zebrafish, therefore protecting against Pb-induced developmental neurotoxicity. In general, our study indicates that CGA, NCGA, and CCGA could be promising agents for treating neurotoxicity induced by Pb, and CCGA shows the strongest detoxifying activity.

Toxicity of different zinc oxide nanomaterials and dose-dependent onset and development of Parkinson's disease-like symptoms induced by zinc oxide nanorods

With the increasing applications in various fields, the release and accumulation of zinc oxide (ZnO) nanomaterials ultimately lead to unexpected consequences to environment and human health. Therefore, toxicity comparison among ZnO nanomaterials with different shape/size and their adverse effects need better characterization. Here, we utilized zebrafish larvae and human neuroblastoma cells SH-SY5Y to compare the toxic effects of ZnO nanoparticles (ZnO NPs), short ZnO nanorods (s-ZnO NRs), and long ZnO NRs (l-ZnO NRs). We found their developmental- and neuro-toxicity levels were similar, where the smaller sizes showed slightly higher toxicity than the larger sizes. The developmental neurotoxicity of l-ZnO NRs (0.1, 1, 10, 50, and 100 μg/mL) was further investigated since they had the lowest toxicity. Our results indicated that l-ZnO NRs induced developmental neurotoxicity with hallmarks linked to Parkinson's disease (PD)-like symptoms at relatively high doses, including the disruption of locomotor activity as well as neurodevelopmental and PD responsive genes expression, and the induction of dopaminergic neuronal loss and apoptosis in zebrafish brain. l-ZnO NRs activated reactive oxygen species production, whose excessive accumulation triggered mitochondrial damage and mitochondrial apoptosis, eventually leading to PD-like symptoms. Collectively, the developmental- and neuro-toxicity of ZnO nanomaterials was identified, in which l-ZnO NRs harbors a remarkably potential risk for the onset and development of PD at relatively high doses, stressing the discretion of safe range in view of nano-ZnO exposure to ecosystem and human beings.

Using Zebrafish to Analyze the Genetic and Environmental Etiologies of Congenital Heart Defects

Congenital heart defects (CHDs) are among the most common human birth defects. However, the etiology of a large proportion of CHDs remains undefined. Studies identifying the molecular and cellular mechanisms that underlie cardiac development have been critical to elucidating the origin of CHDs. Building upon this knowledge to understand the pathogenesis of CHDs requires examining how genetic or environmental stress changes normal cardiac development. Due to strong molecular conservation to humans and unique technical advantages, studies using zebrafish have elucidated both fundamental principles of cardiac development and have been used to create cardiac disease models. In this chapter we examine the unique toolset available to zebrafish researchers and how those tools are used to interrogate the genetic and environmental contributions to CHDs.

Evaluation of the Developmental Toxicity Induced by E804 in Zebrafish Embryos

E804, a derivative of indirubin, have multi-biological activities such as anticancer and anti-inflammatory activities, but little is known about its developmental toxicity. In this study, we investigated the toxicity of E804 on the developments of zebrafish embryos. Our results showed that E804 treatment caused a significant increase of the malformation rate compared with the control groups. Pericardial edema and curved body shape were the most morphological abnormalities observed in E804-treated group. The hatching rates and body length of the zebrafish larvae was significantly decreased in E804-treated groups. E804 also affect the development of heart, liver, phagocytes and vascular formation. Further studies showed that the level of reactive oxygen species was significantly increased. The activity of total superoxide dismutase decreased and the concentration of malondialdehyde were increased. Much more apoptotic cells were detected in E804-treated group, compared with the control. In addition, gene-expression results showed that the pathways of oxidative stress and apoptosis were provoked in E804 treated groups. Taken together, our findings will be helpful to understanding E804-induced developmental toxicity and the underlying mechanism.

α-asarone induces cardiac defects and QT prolongation through mitochondrial apoptosis pathway in zebrafish

α-asarone is a natural phenylpropene found in several plants, which are widely used for flavoring foods and treating diseases. Previous studies have demonstrated that α-asarone has many pharmacological functions, while some reports indicated its toxicity. However, little is known about its cardiovascular effects. This study investigated developmental toxicity of α-asarone in zebrafish, especially the cardiotoxicity. Zebrafish embryos were exposed to different concentrations of α-asarone (1, 3, 5, 10, and 30 μM). Developmental toxicity assessments revealed that α-asarone did not markedly affect mortality and hatching rate. In contrast, there was a concentration-dependent increase in malformation rate of zebrafish treated with α-asarone. The most representative cardiac defects were increased heart malformation rate, pericardial edema areas, sinus venosus-bulbus arteriosus distance, and decreased heart rate. Notably, we found that α-asarone impaired the cardiac function of zebrafish by prolonging the mean QTc duration and causing T-wave abnormalities. The expressions of cardiac development-related key transcriptional regulators tbx5, nkx2.5, hand2, and gata5 were all changed under α-asarone exposure. Further investigation addressing the mechanism indicated that α-asarone triggered apoptosis mainly in the heart region of zebrafish. Moreover, the elevated expression of puma, cyto C, afap1, caspase 3, and caspase 9 in treated zebrafish suggested that mitochondrial apoptosis is likely to be the main reason for α-asarone induced cardiotoxicity. These findings revealed the cardiac developmental toxicity of α-asarone, expanding our knowledge about the toxic effect of α-asarone on living organisms.

BID and the α-bisabolol-triggered cell death program: converging on mitochondria and lysosomes

α-Bisabolol (BSB) is a plant-derived sesquiterpene alcohol able to trigger regulated cell death in transformed cells, while deprived of the general toxicity in several mouse models. Here, we investigated the involvement of lysosomal and mitochondrial compartments in the cytotoxic effects of BSB, with a specific focus on the BH3-only activator protein BID. We found that BSB particularly accumulated in cancer cell lines, displaying a higher amount of lipid rafts as compared to normal blood cells. By means of western blotting and microscopy techniques, we documented rapid BSB-induced BID translocation to lysosomes and mitochondria, both of them becoming dysfunctional. Lysosomal membranes were permeabilized, thus blocking the cytoprotective autophagic flux and provoking cathepsin B leakage into the cytosol. Multiple flow cytometry-based experiments demonstrated the loss of mitochondrial membrane potential due to pore formation across the lipid bilayer. These parallel events converged on neoplastic cell death, an outcome significantly prevented by BID knockdown. Therefore, BSB promoted BID redistribution to the cell death executioner organelles, which in turn activated anti-autophagic and proapoptotic mechanisms. This is an example of how xenohormesis can be exploited to modulate basic cellular programs in cancer.

Synergistic effects of Pb and repeated heat pulse on developmental neurotoxicity in zebrafish

Pollutant discharges to the aquatic environment often contain multiple environmental stressors, affecting aquatic organisms. To mimic the discharges from nuclear and industry facilities, the combined effects of two independent types of stressors, heavy metal Pb and repeated heat pulse were addressed in this study. We investigated the developmental toxicity of combined treatment, especially its toxic effects on zebrafish neurodevelopment. The normal embryos at 4 hpf were exposed to 0.2 mM of Pb dissolved in the bathing medium with different temperatures (30, 32, and 34 °C) and then maintained in an incubator at 28 °C. After performing above treatment once every 24 h for 6 days, we found that combined treatment significantly affected neural development, including loss of dopaminergic (DA) neurons and brain vasculature, disruption of locomotor activity and neurodevelopmental genes expression in a temperature-dependent manner as compared to the Pb alone exposure group, indicating that repeated heat pulse enhances these negative impacts induced by Pb. In contrast, no apparent toxicity was observed in repeated heat pulse alone groups, suggesting that Pb treatment reduces thermal tolerance in zebrafish, which emphasized the importance to evaluate synergistic effects of Pb and repeated heat pulse. Moreover, repeated heat pulse aggravated Pb-induced apoptosis in the zebrafish brain. Further study of the underlying mechanism suggested that Caspase 3 regulated apoptosis was involved in this process. Taken together, our findings shed light on the full understanding of toxic effects of discharges from industrial applications on living organisms and its environmental impact.