Yolk Sac Edema Research Articles

Formulation and Evaluation of the Antimicrobial Potential and Embryotoxicity of Betanin-Zinc Nanoparticles

Introduction: This study explores the green synthesis of betanin-based ZnO nanoparticles, with emphasis on their characterization, antimicrobial potential, and toxicity evaluation. Materials and methods: Zinc oxide nanoparticles (ZnO NPs) were produced using betanin isolated from Beta vulgaris, zinc hexahydrate, and 0.5M NaOH. To verify their structural and morphological characteristics, the produced betanin zinc oxide nanoparticles (BT-ZnO NPs) were examined using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Candida albicans were among the bacterial strains against which the antibacterial activity of these green-synthesised BT-ZnO NPs was assessed. Concurrently, zebrafish (Danio rerio) embryos were subjected to different amounts (10, 50, and 100 µg/mL) in order to perform embryotoxicity experiments. Results: SEM analysis showed that BT-ZnO NPs are irregularly shaped with a tendency to aggregate, which may enhance surface area. FTIR confirmed functional groups like phenols and amines, aiding nanoparticle stability. XRD indicated a composition of 52.5% crystalline and 47.5% amorphous content, supporting structural stability and bioactivity. Anti-microbial potential of BT-ZnO NPs shows notable inhibition at higher concentrations. In contrast, Candida albicans exhibited resistance to the nanoparticles. Embryotoxicity results showed that the ZnO NPs caused decreased survival rates, hatching delays, and morphological abnormalities in the zebrafish embryos, such as tail malformations and yolk sac oedema in the 100 µg/mL treatment group. Conclusion: While this study demonstrates the efficacy of BT-ZnO NPs as strong antimicrobial agents, it also emphasizes the need for caution regarding their environmental and health impacts, particularly at higher concentrations.

Propanil impairs organ development in zebrafish by inducing apoptosis and inhibiting mitochondrial respiration

Propanil, an anilide herbicide, has frequently been detected in surface waters in Europe and the United States, largely due to its use in paddy cultivation areas. Particularly in specific regions like Sri Lanka, propanil is considered a potential cause of certain diseases and toxicities due to its high environmental runoff; however, there has been little research on its developmental toxicity. In the present study, we confirmed the developmental toxicity of propanil in zebrafish embryos exposed to 0, 2, 5, and 6 mg/L based on the LC50 value. Propanil exposure in embryos induced morphological changes, including decreased body length and eye size, and increased the heart and yolk sac edema. It increased the number of apoptotic cells in the brains and eyes of zebrafish larvae by 214 % and 184 %, respectively. Propanil-treated embryos exhibited altered mitochondrial metabolism, reducing basal respiration by 28 %, maximal respiration by 24 %, and ATP production by 38 %. These alterations induced organ defects in transgenic zebrafish models (cmlc2:DsRed, flk1:EGFP, olig2:DsRed, lfabp:DsRed;elastase:EGFP, and insulin:EGFP). It induced cardiovascular toxicity, as confirmed by the reduced atrial area, cerebrovascular intensity, and intersegmental vessels. Additionally, propanil decreased the fluorescence intensity of neurons, liver, and pancreas. Collectively, this study indicates that propanil causes early developmental toxicity through apoptosis and mitochondrial dysfunction. It presents a new perspective on how mitochondrial dysfunction, previously unreported in toxicity studies of other anilide herbicides, may affect developmental toxicity.

Neurotoxic and developmental effects of scented incense stick smoke: Network toxicology and zebrafish model study

Burning incense sticks is a traditional practice in many cultures, especially in Southeast Asia. While it is often regarded as sacred and beneficial, modern incense sticks contain various chemicals that can pose health risks. A GCMS analysis of the ICS revealed potential compounds. Network toxicology revealed that ICS contains compounds violating Lipinski's rule of five, leading to potential neurotoxic effects. Key pathways affected include neuroactive ligand-receptor interaction and calcium signaling, associated with neurodegenerative diseases like Parkinson's and Alzheimer's. Significant genes involved are STAT3, BCL2, and MTOR, emphasizing the chemical hazards of ICS exposure. We investigated the toxicity of ICS using zebrafish (Danio rerio) embryos as a mode. ICS exposure resulted in a dose-dependent increase in toxicity. High concentrations (7 and 14 µg/ml) led to immediate mortality, while lower concentrations (0.1, 0.3, 0.5, and 1 µg/ml) caused developmental defects such as yolk sac edema, skeletal malformations, and pericardial edema. Mortality rates increased with higher concentrations, confirming dose-dependent ICS exposure caused hypoactive locomotion, with reduced distance traveled and velocity toxicity. Higher concentrations of ICS led to increased ROS levels and cellular damage, as evidenced by enhanced staining levels. A dose-dependent increase in lipid peroxidation (DPPP assay) and lipid accumulation (Nile red assay) was observed. Higher ICS concentrations led to significant oxidative damage to lipids and increased lipid deposition. Enzymatic assays showed that ICS exposure significantly decreased the activities of antioxidant enzymes SOD and CAT, indicating impaired antioxidant defense, while increasing LDH activity, signaling tissue damage and cytotoxicity. Gene expression analysis revealed downregulation of SOD1 and CAT genes, upregulation of inflammatory genes TNF-α and IL-1β, and increased expression of the apoptotic gene p53 with decreased expression of Bcl-2 and BDNF. These findings highlight ICS's potential to cause oxidative stress, inflammation, apoptosis, and neurodevelopmental impairments.

Developmental Toxicity and Teratogenic Effects of Dicarboximide Fungicide Iprodione on Zebrafish (Danio rerio) Embryos

Iprodione (IDN) is a broad-spectrum fungicide used to treat various fungal infections in plants. Despite its extensive use, assessment of its toxicity in aquatic organisms remains incomplete. This study investigated the deleterious effects of IDN using zebrafish (ZF) as a model organism. ZF embryos, beginning at 2 h post-fertilization (hpf), were exposed to IDN (3.75–40 mg/L), and both mortality and deformities were assessed. The impact of IDN on mortality was concentration-dependent and significant from 14 mg/L. Importantly, IDN induced several deformities at sublethal concentrations, including abnormal somites, reduced retinal pigment accumulation, yolk sac edema, hatching failure, abnormal swim bladders, and spinal curvature. The EC50 values for IDN-induced deformities were 3.44 ± 0.74 to 21.42 ± 6.00 mg/L. The calculated teratogenic index values for all deformities were above 1, indicating that IDN is teratogenic to ZF. IDN-exposed ZF also displayed abnormalities in touch-evoked escape responses. IDN significantly affected heart rate and blood flow, and induced pericardial edema and hyperemia in a concentration-dependent manner, suggesting its influence on cardiac development and the function of ZF. In conclusion, these results suggest that IDN exerts toxic effects on ZF embryos, affecting mortality, development, and behavior.

Developmental toxicity in zebrafish embryos exposed to single, binary, and tertiary mixtures of Cd, Pb, and As

The present study was carried out to investigate developmental toxicity to zebrafish upon exposure singly to cadmium chloride monohydrate (25 µg/L), or lead acetate (40 µg/L), or arsenic trioxide (40 µg/L), and their toxicological interactions upon exposure to combinations of Cd + Pb, Pb + As, Cd + As, and Cd + Pb + As for 120 h post fertilization. Cumulative mortality at 72, 96, and 120 h were significantly higher in all toxicity groups. Cd, Pb, and Pb + As exposure caused 92–100% mortality at 96 h of the exposure. The highest reduction of hatching rate was observed in the Pb + As group followed by the Cd + Pb group. The heart rate was significantly decreased in Cd, As, Cd + Pb, and Cd + Pb + As groups as compared to the control group. Body length, eye size, and cranium size were significantly affected in most of the toxicity groups. The exposure of Cd and Pb increased yolk sac size in the larvae as compared to other treatments. The Pb and Cd exposure group exhibited more tail and spinal deformities. The Cd + Pb exposure group exhibited pericardial and yolk sac edema in the larvae. There may be a possibility of toxicological interaction among Cd, Pb, and As, and may cause developmental defects in fish at the early life stages.

Sodium Fluoride Exposure Induces Developmental Toxicity and Cardiotoxicity in Zebrafish Embryos.

Fluorosis is a worldwide public health problem, in which the heart is an important target organ. However, studies on its toxicological mechanism in embryonic development are limited. This study assessed the toxicity of sodium fluoride (NaF) toward zebrafish embryos. We determined the mortality, hatching rate, phenotypic malformation, heart function, and morphology of zebrafish embryos after exposure to NaF. Subsequently, the molecular mechanism was revealed using high-throughput RNA sequencing analysis. The expression levels of key genes for heart development were detected using quantitative real-time reverse transcription PCR. The 50% lethal concentration (LC50) value of NaF toward zebrafish embryos at 96h post-fertilization was 335.75mg/L. When the concentration of NaF was higher than 200mg/L, severe deformities, such as pericardial edema, yolk sac edema, spine curvature, shortened body length, reduced head area, and eye area, were observed. The heart rate of the embryos exposed to NaF decreased in a dose-dependent fashion. The distance between the sinus venosus and bulbus arteriosus was significantly increased in the NaF-exposed group compared with that in the control group. The stroke volume and cardiac output decreased significantly in the NaF groups. Compared with the control group, the expression levels of Gata4, Tbx5a, Hand2, Tnnt2c, Nppa, and Myh6 were significantly increased in the NaF-treated group. Through transcriptome sequencing, 1354 differentially expressed genes (DEGs) were detected in the NaF (200mg/L) treated groups, including 1253 upregulated genes and 101 downregulated genes. Gene ontology functional analysis and Kyoto Encyclopedia of Genes and Genomes pathway analyses of the DEGs showed that cardiac-related pathways, such as actin cytoskeleton regulation, Jak-Stat, PI3k-Akt, and Ras, were activated in the NaF-exposed group. This study revealed the underlying mechanism of fluoride-induced cardiac morphological and functional abnormalities and provides clues for the clinical prevention and treatment of fluorosis.

Toxicity and Metabolomic Dysfunction Invoked by Febrifugin, a Harmful Component of Edible Nut of Swietenia macrophylla.

Swietenia macrophylla fruit is a valuable and historically significant medicinal plant with anti-hypertension and anti-diabetes. We identified a toxic component, Febrifugin, from the edible part of the nut following zebrafish toxicity-guided isolation. Febrifugin is a mexicanolide-type limonoid compound. The toxic factor induced acute toxicity in zebrafish, including yolk sac edema and pericardial edema, reduced body length, decreased melanin deposition, and presented acute skeletal developmental issues. Further exploration of the acute toxicity mechanism through metabolomics revealed that Febrifugin caused significant changes in 13 metabolites in zebrafish larvae, which are involved in the pentose phosphate, tricarboxylic acid (TCA) cycle, and amino acid biosynthesis. The bioassay of oxidative stress capacity and qRT-PCR measurement showed that the compound significantly affected the h6pd gene in the pentose phosphate pathway and the mRNA expression of cs, idh3a, fh, and shda genes in the TCA cycle, leading to reactive oxygen species (ROS) accumulation and a notable decrease in glutathione (GSH) activity in zebrafish. These findings provide a basis for the rational use of S. macrophylla as a medicinal plant and raise awareness of the safety of medicinal plants.

Embryotoxicity and biochemical changes of clioquinol (CQ) and their impact on zebrafish (Danio rerio): An environmental safety concern

Antibiotic residues and their conversion into toxic products have the potential to place human health at risk and ecosystem, which is precisely the continued accumulation of antibiotics in the environment has greatly alarmed humans and aquatic animals. This work sought to assess the possible impacts of clioquinol (CQ) on hepatotoxicity, teratogenicity, and biochemical alterations in zebrafish adults and embryos. The study examined the acute toxicity of CQ treatment to zebrafish embryos, adults, and 96-hour post fertilisation (hpf), in addition to the teratogenicity of CQ to embryonic and sac-fry stages. The lethal toxicity indicates that the 96 h LC50 values of CQ treated with 48, 72, and 96- hpf larvae; adult fish were 4.78, 3.75, 2.69; 10.86, 8.75, and 6.55 mg/L. This finding implies that zebrafish were more susceptible to CQ in their early life stages than in their adult stages, which is in accordance with in silico analyses using ECOSAR and T.E.S.T. At doses of 5 mg/L or higher, CQ would suppress zebrafish embryonic motility, heart rate, hatching rate, and body length of surviving larvae. Furthermore, to pericardial oedema, CQ also resulted in morphological abnormalities, including tail, spine, and yolk sac oedema. Histopathological alterations were noted in the kidney, intestines, gills, liver, and brain. Glutathione-S-transferase, catalase, and superoxide dismutase levels in the adult zebrafish decreased in a dose-dependent manner following 96 h of treatment. In addition, the adult zebrafish exposed to CQ had significantly downregulated levels of SOD, growth hormone 1, and TNF-α in the liver and blood. The findings provided the foundation for further research into the mechanism behind CQ toxicity in zebrafish, as they demonstrated that CQ had notable detrimental effects on zebrafish at different life stages.

Evaluating the embryotoxicity of benzophenone-based photoinitiators in stem cells and zebrafish embryos

Benzophenones (BPs) are widely used as photoinitiators (PIs) or printing inks in food packaging, which may migrate into foods. However, the toxicity information of some BP analogues, such as 4,4′-bis(diethylamino)-benzophenone (DEAB), 4-phenylbenzophenone (4-PBP), 4 (hydroxymethyl)benzophenone (4-HMBP), those are used as PIs is lacking. Developmental toxicity is a health concern associated with PIs exposure. Recently, alternative non-in vivo methods have been proposed to evaluate the concerned chemicals or better understand the modes of action of certain toxicological endpoints. In this study, using in silico methods, we predicted that BP, DEAB, 4-PBP and 4-HMBP might exhibit developmental toxicity. However, we found that only DEAB is strong embryotoxic and disturbs the early differentiation of mouse embryonic stem cells into three germ layers and cardiomyocytes. DEAB treatment also prevented cardiomyocyte differentiation in human induced pluripotent stem cells (hiPSCs) on day 10. However, BP, 4-PBP and 4-HMBP had no similar effects on cardiomyocyte differentiation on day 10. Transcriptomic analysis revealed that treatment with DEAB significantly decreased the mRNA levels of differentiation-related transcription factors SOX17 and FOXA1, in hiPSCs on day 4. Furthermore, DEAB treatment caused tail malformations and yolk sac edema in zebrafish embryos. To conclude, DEAB may be embryotoxic because it disturbs the early differentiation of stem cells. Further studies are warranted to better understand the health effects of DEAB exposure.

Effects of different light qualities on embryonic development of Sepia pharaonis

To investigate the impact of different light qualities (red, blue, green, yellow, and white light) on the embryonic development of Sepia pharaonis, this experiment studied the effects of different light qualities on the timing of embryonic development, incubation period, hatching rate, malformation rate, weight of hatchlings, and survival rate on the 7th day after hatching. The findings demonstrated a significant influence of different light qualities on the embryonic development of S. pharaonis (P<0.05). Specifically, red and blue light led to increased occurrences of phenomena such as yolk surface cracking, cell autolysis, coagulation of cells in the animal pole, yolk sac edema, malformations in endoskeleton development, and decreased pigmentation and whitening of the body surface compared to the control group (white light). Conversely, green light showed a tendency to reduce these phenomena. The hatching rate and hatching cuttlefish weight were highest under green and yellow light conditions, with significantly greater survival rate on the 7th day after hatching compared to red, blue, and white light conditions. Furthermore, the malformation rate was notably lower under green light conditions compared to other light groups. Red and blue light conditions exhibited the shortest hatching periods, significantly outpacing other light groups. In conclusion, green light appears advantageous for enhancing hatching rate, the quality and health of hatched larvae, reducing malformation occurrences and embryonic mortality, and improving overall hatching quality.

Toxicological effect of acetaminophen, metamizole, and nimesulide cocktail on early developmentof zebrafish.

Several countries' most incorrectly discarded medicines are acetaminophen (ACM), metamizole (MTZ), and nimesulide (NMS). These xenobiotics easily reach the aquatic environment; such contamination is very important for the health of humans and other species, yet little explored. To evaluate the cocktail effect of ACM, MTZ, and NMS during zebrafish's initial development. Zebrafish embryos 6-8h post-fertilization (hpf) were exposed to different concentrations of ACM, MTZ, and NMS, separately, to obtain the 50% lethal concentrations (LC50). Next, the embryos were exposed to distinct concentrations of the cocktail (LC50/2, LC50/5, LC50/10, and LC50/20) in a semi-static system. Samples were analyzed 0, 24, 48, and 96h after exposure, and the drugs' concentrations in E3 medium were assessed by high-performance liquid chromatography. For embryotoxicity evaluation, the mortality, hatching, and heart rates; total length; and pericardial and yolk sac areas were determined. In addition, body malformations, edemas, presence of pigmentation, and histopathological assessments were also recorded. The LC50 values obtained for MTZ, ACM, and NMS were 4.69 mgmL-1, 799.98 μgmL-1, and 0.92 μgmL-1, respectively. No difference was observed between the drugs' nominal and observed concentrations at each time point. The cocktail significantly induced mortality and decreased hatching in the LC50/10, LC50/5, and LC50/2 groups. Additionally, body malformations, pigmentation loss, and yolk sac and pericardial edemas were observed in the cocktail groups. The cocktail groups' larvae had decreased total length and slower heart rates compared to the controls (p < 0.05). The histopathological assessment showed that yolk sac edema promoted severe histological changes in the esophageal-intestine junction and intestine in larvae treated with cocktails. Moreover, PAS-positive structures decreased in the esophageal-intestine junction, intestine, and liver in larvae exposed to pharmaceutical cocktails. This study's findings suggest the cocktail of ACM, MTZ, and NMS may be hazardous to aquatic organisms in case of environmental contamination.

Co-occurrence of azorubine and bisphenol A in beverages increases the risk of developmental toxicity: A study in zebrafish model

The prevalent use of Azorubine (E122) and the unintentional food additive, Bisphenol A (BPA), in ready-to-drink (RTD) beverages raises significant health concerns, especially for children. The combined impact on embryonic development must be explored despite individual safety assessments. Our investigation revealed that the combined exposure of E122 and BPA at beverage concentration significantly induces mortality and morphological deformities, including reduced growth, pericardial edema, and yolk sac edema. The co-exposure triggers oxidative stress, impairing antioxidant enzyme responses and resulting in lipid and cellular damage. Notably, apoptotic cells are observed in the neural tube and notochord of the co-exposed larvae. Critical genes related to the antioxidant response elements (nrf2, ho1, and nqo1), apoptosis activation (bcl2, bax, and p53), and pro/anti-inflammatory cytokines (nfkb, tnfa, il1b, tgfb, il10, and il12) displayed substantial changes, highlighting the molecular mechanisms. Behavior studies indicated hypo-locomotion with reduced thigmotaxis and touch response in co-exposed larvae, distinguishing it from individual exposures. These findings underscore the neurodevelopmental impacts of E122 and BPA at reported beverage concentrations, emphasizing the urgent need for comprehensive safety assessments, particularly for child consumption.

Evaluation of the citalopram toxicity on early development of zebrafish: Morphological, physiological and biochemical responses

Citalopram, an antidepressant drug have been detected in different environmental matrices due to its high consumption. Previous study has proved that citalopram may alter the behaviour of aquatic organisms at environmentally relevant concentrations. However, scientific knowledge is still lacking on the ecotoxicological effects of citalopram on aquatic organisms. For this reason, the present study is aimed to investigate the potential toxicity of citalopram in terms of development, antioxidant, neurotoxicity, apoptosis, lipogenesis, and bone mineralization in embryonic and larval zebrafish (Danio rerio) at environmentally relevant concentrations. We noticed that citalopram exposure at 1 and 10 μg/L concentration delays hatching and heartbeat at 24, 48, 72 and 96 hpf. Exposure to citalopram also significantly increased mortality at 10 μg/L. Abnormal development with yolk sac edema, pericardial edema and scoliosis were also observed after citalopram treatment. In addition, citalopram significantly (P < 0.001) induced superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and lipid peroxidation (LPO) levels. A significant decrease in acetylcholine esterase (AChE) activity was also observed in citalopram exposed groups. We found significant dose-and time-dependent increases in apoptosis, lipogenesis, and bone mineralization. In conclusion, the findings of the present study can provide new insights on the ecotoxicity of citalopram in the aquatic environment.

Electrochemical oxidation of Florfenicol in aqueous solution with mixed metal oxide electrode: Operational factors, reaction by-products and toxicity evaluation

Veterinary antibiotics have become an emerging pollutant in water and wastewater sources due to excess usage, toxicity and resistance to traditional water and wastewater treatment. The present study explored the degradation of a model antibiotic- Florfenicol (FF) using electrochemical oxidation (EO) with Ti–RuO2/IrO2 anode. The anode material was characterized using SEM-EDS studies expressing stable structure and optimal interaction of the neighboring metal oxides with each other. The EDS results showed the presence of Ru, Ir, Ti, O and C elements with 6.44%, 2.57%, 9.61%, 52.74% and 28.64% atomic weight percentages, respectively. Optimization studies revealed pH 5, 30 mA cm−2 current density and 0.05 M Na2SO4 for 5 mg L−1 FF achieved 90% TOC removal within 360 min treatment time. The degradation followed pseudo-first order kinetics. LC-Q-TOF-MS studies revealed six predominant byproducts illustrating hydroxylation, deflourination, and dechlorination to be the major degradation mechanisms during the electrochemical oxidation of FF. Ion chromatography studies revealed an increase in Cl−, F− and NO3− ions as treatment time progressed with Cl− decreasing after the initial phase of the treatment. Toxicity studies using Zebrafish (Danio rerio) embryo showed the treated sample to be toxic inducing developmental disorders such as pericardial edema, yolk sac edema, spinal curvature and tail malformation at 96 h post fertilization (hpf). Compared to control, delayed hatching and coagulation were observed in treated embryos. Overall, this study sets the stage for understanding the effect of mixed metal oxide (MMO) anodes on the degradation of veterinary antibiotic-polluted water and wastewater sources using electrochemical oxidation.

Assessment of toxicity of pyriproxyfen, Bacillus thuringiensis, and malathion and their mixtures used for mosquito control on embryo-larval development and behavior of zebrafish.

Pyriproxyfen (PPF), Bacillus thuringiensis israelensis (BTI), and malathion (MLT) are widely used worldwide to control the population of mosquitos that transmit arboviruses. The current work aimed to evaluate the toxicity of these single pesticides and their binary mixtures of PPF + BTI, PPF + MLT, and MLT + BTI on the embryo-larval stage of zebrafish (Danio rerio) as an animal model. Epiboly, mortality, apical endpoints, affected animals, heart rate, morphometric, thigmotaxis, touch sensitivity, and optomotor response tests were evaluated. PPF and MLT and all mixtures reduced the epiboly percentage. Mortality increased significantly in all exposed groups, except BTI, with MLT being the most toxic. The observed apical endpoints were pericardial and yolk sac edemas, and tail and spine deformation. Exposure to MLT showed a higher percentage of affected animals. A reduction in heart rate was also observed in MLT- and PPF + MLT-exposed groups. The PPF + MLT mixture decreased head measurements. Behavioral alterations were observed, with a decrease in thigmotaxis and touch sensitivity responses in PPF + MLT and MLT + BTI groups. Finally, optomotor responses were affected in all groups. The above data obtained suggest that the MLT + PFF mixture has the greatest toxicity effects. This mixture affected embryo-larval development and behavior and is close to the reality in several cities that use both pesticides for mosquito control rather than single pesticides, leading to a reevaluation of the strategy for mosquito control.

Cadmium and ketoprofen accumulation influences aquatic ecosystem demonstrated using in-vivo zebrafish model

The growing concern about pollution and toxicity in aquatic as well as terrestrial organisms is predominantly caused due to waterborne exposure and poses a risk to environmental systems and human health. This study addresses the co-toxic effects of cadmium (Cd) and ketoprofen (KPF), representing heavy metal and pharmaceutical discharge pollutants, respectively, in aquatic ecosystems. A 96-h acute toxicity assessment was conducted using zebrafish embryos. The results indicated that high dosages of KPF (10, 15, and 100 µg/mL) and Cd (10 and 15 µg/mL) reduced survivability and caused concentration-dependent deformities such as scoliosis and yolk sac edema. These findings highlight the potential defects in development and metabolism, as evidenced by hemolysis tests demonstrating dose-dependent effects on blood cell integrity. Furthermore, this study employs adult zebrafish for a 42-day chronic exposure to Cd and KPF (10 and 100 µg/L) alone or combined (10 + 10 and 100 + 100 µg/L) to assess organ-specific Cd and KPF accumulation in tissue samples. Organ-specific accumulation patterns underscore complex interactions impacting respiratory, metabolic, and detoxification functions. Prolonged exposure induces reactive oxygen species formation, compromising antioxidant defense systems. Histological examinations reveal structural changes in gills, gastrointestinal, kidney, and liver tissues, suggesting impairments in respiratory, osmoregulatory, nutritional, and immune functions. This study emphasizes the importance of conducting extensive research on co-toxic effects to assist with environmental risk assessments and safeguard human health and aquatic ecosystems.

Developmental toxicity assay of xanthatin in zebrafish embryos

Xanthatin (XAN), a xanthanolide sesquiterpene lactone, isolated from Chinese herb, Xanthium strumarium L, has various pharmacological activities, such as antitumor activity and anti-inflammatory. However, little is known about its potential toxicity and the mechanism. Here, zebrafish model was used to study the developmental toxicity in vivo. Our results indicated that xanthatin increased the mortality and led to the morphological abnormalities including pericardial edema, yolk sac edema, curved body shape and hatching delay. Furthermore, xanthatin damaged the normal structure and/or function of heart, liver, immune and nervous system. ROS elevation and much more apoptosis cells were observed after xanthatin exposure. Gene expression results showed that oxidative stress-related genes nrf2 was inhibited, while oxidative stress-related genes (keap1 and nqo1) and apoptotic genes (caspase3, caspase9 and p53) were increased after xanthatin exposure. Mitophagy related genes pink1 and parkin, and wnt pathway (β-catenin, wnt8a and wnt11) were significantly increased after xanthatin exposure. Taken together, our finding indicated that xanthatin induced developmental toxicity, and the ROS elevation, apoptosis activation, dysregulation of mitophagy and wnt pathways were involved in the toxicity caused by xanthatin.

Teratogenic Effects of Di(2-Ethylhexyl) Phthalate (DEHP) on Zebrafish Embryos

Developmental toxicity studies help to understand the impact of a pollutant on this crucial phase of the living organisms which can affect their population dynamics. Zebrafish has become an ideal model for studying environmental and embryo toxicity. The present study was carried out using zebrafish embryos for assessing the environmental toxicity of Di(2-ethylhexyl) phthalate (DEHP) which is universally considered to be an omnipresent environmental contaminant as it is the most widely used plasticizer. The embryos were exposed to DEHP for a range of five concentrations of 0.2, 20, 80, 140 and 200 μg/L for the duration of 96 hours. The treatment resulted in increased mortality and decreased hatch rate, hatchability and heartrate. It also induced teratogenic endpoints like yolk sac edema, pericardial edema and spinal deformity in the embryos which increased in dose and time dependent manner.

Effects of developmental exposure to individual and combined PFAS on development and behavioral stress responses in larval zebrafish

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals known for their widespread use and persistence in the environment. Laboratory and epidemiological studies investigating these compounds have signaled their neurotoxic and endocrine-disrupting propensities, prompting further research into their effects on behavioral stress responses and their potential role as risk factors for stress-related disorders such as anxiety and depression. This study elucidates the ramifications of early developmental exposures to individual and combined PFAS on the development and behavioral stress responses of larval zebrafish (Danio rerio), an established model in toxicological research. Wild-type zebrafish embryos were enzymatically dechorionated and exposed to PFOS, PFOA, PFHxS, and PFHxA between 6 and 120 h post-fertilization (hpf). We targeted environmentally relevant concentrations stemming from the USEPA 2016 Hazard Advisory Limit (HAL, 0.07 μg/L) and folds higher (0.35, 0.7, 1.75, and 3.5 μg/L). Evaluations at 120 hpf encompassed mortality, overall development, developmental defects, and larval activity both at baseline stress levels and following exposure to acute stressors (acoustic and visual). Larval exposure to PFOA, PFOS, or PFHxS (0.07 μg/L or higher) elicited significant increases in mortality rates, which capped at 23.1%. Exposure to individual chemicals resulted in limited effects on overall development but increased the prevalence of developmental defects in the body axis, swim bladder, pigmentation, and eyes, as well as the prevalence of yolk sac and pericardial edemas. Larval activity at baseline stress levels and following exposure to acute stimuli was significantly altered. Combined exposure to all four chemicals intensified the breadth of developmental and behavioral alterations, suggesting possible additive or synergistic effects. Our findings shed light on the developmental and neurobehavioral disturbances associated with developmental exposure to PFAS at environmentally relevant concentrations, the added risks of combined exposures to these chemicals, and their possible role as environmental risk factors for stress-related disorders.

Indigo dyes: Toxicity, teratogenicity, and genotoxicity studies in zebrafish embryos

Wastewater released by textile dyeing industries is a major source of pollution. Untreated wastewater released from indigo dyeing operations affects aquatic ecosystems and threatens their biodiversity. We have assessed the toxicity of natural and synthetic indigo dye in zebrafish embryos, using the endpoints of teratogenicity, genotoxicity, and histopathology. The zebrafish embryo toxicity test (ZFET) was conducted, exposing embryos to ten concentrations of natural and synthetic indigo dyes; the 96-hour LC50 values were approximately 350 and 300 mg/L, respectively. Both dyes were teratogenic, causing egg coagulation, tail detachment, yolk sac edema, pericardial edema, and tail bend, with no significant difference in effects between the natural and synthetic dyes. Both dyes were genotoxic (using comet assay for DNA damage). Real-time RT-PCR studies showed upregulation of the DNA-repair genes FEN1 and ERCC1. Severe histological changes were seen in zebrafish larvae following exposure to the dyes. Our results show that indigo dyes may be teratogenic and genotoxic to aquatic organisms, underscoring the need for development of sustainable practices and policies for mitigating the environmental impacts of textile dyeing.