Embryotoxicity of methylparaben to zebrafish (Danio rerio) early-life stages

From Personal Care to Coastal Concerns: Investigating Polyethylene Glycol Impact on Mussel's Antioxidant, Physiological, and Cellular Responses

Pharmaceutical and personal care products (PPCPs) containing persistent and potentially hazardous substances have garnered attention for their ubiquitous presence in natural environments. This study investigated the impact of polyethylene glycol (PEG), a common PPCP component, on Mytilus galloprovincialis. Mussels were subjected to two PEG concentrations (E1: 0.1 mg/L and E2: 10 mg/L) over 14 days. Oxidative stress markers in both gills and digestive glands were evaluated; cytotoxicity assays were performed on haemolymph and digestive gland cells. Additionally, cell volume regulation (RVD assay) was investigated to assess physiological PEG-induced alterations. In the gills, PEG reduced superoxide dismutase (SOD) activity and increased lipid peroxidation (LPO) at E1. In the digestive gland, only LPO was influenced, while SOD activity and oxidatively modified proteins (OMPs) were unaltered. A significant decrease in cell viability was observed, particularly at E2. Additionally, the RVD assay revealed disruptions in the cells subjected to E2. These findings underscore the effects of PEG exposure on M. galloprovincialis. They are open to further investigations to clarify the environmental implications of PPCPs and the possibility of exploring safer alternatives.

The combined effects of preservative chemicals in consumer products: An analysis using embryonic and adult zebrafish

Benzisothiazolinone (BIT) and propyl paraben (PP) are preservatives in cleaning products; however, their toxicities are not well understood. In this study, zebrafish embryos were exposed to BIT, PP, and mixtures of both for 96 h to investigate the effects on growth hormone (GH), insulin-like growth factor-1 (IGF-1), and the transcription of 19 genes related to the GH/IGFs axis. Concentrations of BIT and PP were measured in the whole body of larvae. Zebrafish pairs were also exposed to BIT, PP, and mixtures for 21 d to evaluate the effects on sex hormones, histology in gonad, and transcription of 22 genes related to the hypothalamus-pituitary-gonad axis and vitellogenin. The mixtures had potentiation effects on development, reproduction, hormones, and gene transcripts than individual exposure. Larvae exposed to 229 μg L-1 BIT, 64.5 μg L-1 PP, and mixtures showed reduced growth. Decreased GH and IGF-1 levels were supported by gene regulation associated with the GH/IGFs axis. In larvae, reactive oxygen species, superoxide dismutase, catalase, and glutathione peroxidase levels were increased under all exposures. The gonadosomatic index in males and number of eggs decreased after mixture exposure. In females exposed to mixtures, the percentage of atretic follicle in ovary was significantly increased. The significant decrease in testosterone in males and significant decrease in 17β-estradiol in females exposed to mixtures suggest anti-estrogenic and anti-androgenic potential. Thus, preservative mixtures in consumer products may be more toxic than the individual substances, which is important for managing the risks of mixing preservatives.

Evaluating quaternium-15 effects on Mytilus galloprovincialis: New insights on physiological and cellular responses

Among personal care products, quaternium-15 is prominently featured as a preservative in items such as shampoos, soaps, shaving products, and cosmetics. The widespread use of these products in people's daily routines contributes to quaternium-15 release into aquatic ecosystems. In this context, the primary aim of the study was to assess the physiological and cellular responses of the digestive gland and gills in Mytilus galloprovincialis to quaternium-15 exposure. Cell viability and the ability of digestive gland cells to regulate their volume were evaluated. Additionally, the expression of the genes involved in oxidative stress response was assessed to further substantiate the compound's harmful effects. Results indicated a significant decrease in both the viability of digestive gland cells and their RVD (regulatory volume decrease) capacity when exposed to a hypotonic solution. Furthermore, impairment of digestive gland cell function was corroborated by the modulation of oxidative stress-related gene expression, including SOD, Cat, as well as Hsp70 and CYP4Y1. Similar gene expression alterations were observed in the gills, reflecting impaired functionality in this vital organ as well. In summary, the outcomes of the study provide conclusive evidence of the toxicity of quaternium-15. This underscores the urgent need to further investigate the toxicological effects of this contaminant on aquatic ecosystems and emphasises the necessity of limiting the use of products containing quaternium-15.

Embryonic and larval exposure to propylparaben induces developmental and long-term neurotoxicity in zebrafish model

Parabens are preservatives found in cosmetics, processed foods, and medications. The harmful repercussions on the central nervous system by one of the most common parabens, propylparaben (PrP), are yet unknown, especially during development. In this study, the neurodevelopmental effects of PrP and long-term neurotoxicity were investigated in the zebrafish model, using an integrated approach. Zebrafish embryos were exposed to two different concentrations of PrP (10 and 1000 μg/L), then larvae were examined for their behavioral phenotypes (open-field behavior, startle response, and circadian rhythmicity) and relevant brain markers (cyp19a1b, pax6a, shank3a, and gad1b). Long-term behavioral and cognitive impacts on sociability, cerebral functional asymmetry and thigmotaxis were also examined on juveniles at 30 dpf and 60 dpf. Moreover, proteomics and gene expression analysis were assessed in brains of 60 dpf zebrafish. Interestingly, thigmotaxis was decreased by the high dose in larvae and increased by the low dose in juveniles. The expression of shank3a and gad1b genes was repressed by both PrP concentrations pointing to possible effects of PrP on neurodevelopment and synaptogenesis. Proteomics analysis evidenced alterations related to brain development and lipid metabolism. Overall, the results demonstrated that early-life exposure to PrP promotes developmental and persistent neurobehavioral alterations in the zebrafish model, affecting genes and protein levels possibly associated with brain diseases.

Physiological impact of personal care product constituents on non-target aquatic organisms

Personal care products (PCPs) are products used in cleaning, beautification, grooming, and personal hygiene. The rise in diversity, usage, and availability of PCPs has resulted in their higher accumulation in the environment. Thus, these constitute an emerging category of environmental contaminants due to the potential of its constituents (chemical and non-chemical) to induce various physiological effects even at lower concentrations (ng/L). For analyzing the impact of the PCPs constituents on the non-target organism about 300 article including research articles, review articles and guidelines were studied from 2000 to 2023. This review aims to firstly discuss the fate and accumulation of PCPs in the aquatic environment and organisms; secondly provides overview of environmental risks that are linked to PCPs; thirdly review the trends, current status of regulations and risks associated with PCPs and finally discuss the knowledge gaps and future perspectives for future research. The article discusses important constituents of PCPs such as antimicrobials, cleansing agents and disinfectants, fragrances, insect repellent, moisturizers, plasticizers, preservatives, surfactants, UV filters, and UV stabilizers. Each of them has been found to display certain toxic impact on the aquatic organisms especially the plasticizers and UV filters. These continuously and persistently release biologically active and inactive components which interferes with the physiological system of the non-target organism such as fish, corals, shrimps, bivalves, algae, etc. With a rise in the number of toxicity reports, concerns are being raised over the potential impacts of these contaminant on aquatic organism and humans. The rate of adoption of nanotechnology in PCPs is greater than the evaluation of the safety risk associated with the nano-additives. Hence, this review article presents the current state of knowledge on PCPs in aquatic ecosystems.

Transcriptome analysis reveals differences in developmental neurotoxicity mechanism of methyl-, ethyl-, and propyl- parabens in zebrafish embryos

Studies on the comparison of developmental (neuro) toxicity of parabens are currently limited, and unharmonized concentrations between phenotypic observations and transcriptome analysis hamper the understanding of their differential molecular mechanisms. Thus, developmental toxicity testing was conducted herein using the commonly used methyl- (MtP), ethyl- (EtP), and propyl-parabens (PrP) in zebrafish embryos. With a benchmark dose of 5%, embryonic-mortality-based point-of-departure (M-POD) values of the three parabens were determined, and changes in locomotor behavior were evaluated at concentrations of 0, M-POD/50, M-POD/10, and M-POD, where transcriptome analysis was conducted to explore the underlying neurotoxicity mechanism. Higher long-chained parabens were more toxic than short-chained parabens, as determined by the M-POD values of 154.1, 72.6, and 24.2 µM for MtP, EtP, and PrP, respectively. Meanwhile, exposure to EtP resulted in hyperactivity, whereas no behavioral effect was observed with MtP and PrP. Transcriptome analysis revealed that abnormal behaviors in the EtP-exposed group were associated with distinctly enriched pathways in signaling, transport, calcium ion binding, and metal binding. In contrast, exposure to MtP and PrP mainly disrupted membranes and transmembranes, which are closely linked to abnormal embryonic development rather than neurobehavioral changes. According to the changes in the expressions of signature mRNAs, tentative transcriptome-based POD values for each paraben were determined as MtP (2.68 µM), EtP (3.85 µM), and PrP (1.4 µM). This suggests that different molecular perturbations initiated at similar concentrations determined the extent and toxicity outcome differently. Our findings provide insight into better understanding the differential developmental neurotoxicity mechanisms of parabens.

Nickel-iron-driven heterogenous bio-electro-fenton process for the degradation of methylparaben

Discharge of emerging contaminants such as parabens in natural water bodies is a grievous concern. Among parabens, methylparaben (MP) is most prevalent due to its extensive usage in personal care and food products and has been purported to trigger hormonal-related diseases. In this regard, the bio-electro-Fenton (BEF) process garners attention for remediating refractory compounds because of its ability to generate in situ hydroxyl radicals (•OH) utilising the energy harvested from electroactive microorganisms. In the present investigation, a Ni-Fe-driven heterogenous BEF system (BEF-MFC) was used to degrade MP from different matrices. At neutral catholyte pH, 99.54 ± 0.22% of MP was removed from an initial concentration of 10 mg/L in 240 min of retention time with an estimated treatment cost of about 1.01 $/m3. The removal rate ameliorated when the catholyte pH was dropped to 3.0 and by imposing an external voltage of 0.5 V, requiring just 120 min to achieve comparable MP removal efficiencies. However, catalyst leaching was higher at acidic pH (leaching of Fe ions = 0.44 mg/L and Ni ions = 0.06 mg/L) and applying external voltage increased the treatment cost slightly to 1.08 $/m3. Further, treatment of 10 mg/L MP-spiked real wastewater at pH of 7.0 with the BEF-MFC attained 85.70 ± 3.30% and 56.50 ± 1.70% reduction in MP and total organic carbon, respectively, in 240 min. In addition, a maximum power density of 205.90 ± 2.27 mW/cm2 was harvested in the BEF-MFC; thus, portraying the dual benefit of Ni-Fe heterogeneous catalyst. Even though, Ni-Fe performed reasonably well as Fenton-cum-cathode catalyst, future endeavours should be poised to fine-tune catalysts to accelerate H2O2 and •OH generation, which will reinforce the scalability of this system.

Zebrafish as model organisms for toxicological evaluations in the field of food science

Food safety has long been an area of concern. The selection of stable and efficient model organisms is particularly important for food toxicology studies. Zebrafish (Danio rerio) are small model vertebrates, and 70% of human genes have at least one zebrafish ortholog. Zebrafish have advantages as model organisms due to their short life cycle, strong reproductive ability, easy rearing, and low cost. Zebrafish embryos have the advantage of being sensitive to the breeding environment and thus have been used as biosensors. Zebrafish and their embryos have been widely used for food toxicology assessments. This review provides a systematic and comprehensive summary of food toxicology studies using zebrafish as model organisms. First, we briefly introduce the multidimensional mechanisms and structure-activity relationship studies of food toxicological assessment. Second, we categorize these studies according to eight types of hazards in foods, including mycotoxins, pesticides, antibiotics, heavy metals, endocrine disruptors, food additives, nanoparticles, and other food-related ingredients. Finally, we list the applications of zebrafish in food toxicology studies in line with future research prospects, aiming to provide a valuable reference for researchers in the field of food science.

Early-life exposure to environmentally relevant concentrations of triclocarban impairs ocular development in zebrafish larvae

Triclocarban (TCC), is an antimicrobial component in personal care products and it is one of the emerging contaminants since it has been detected in various environmental matrices. Its presence in human cord blood, breast milk, and maternal urine raised issues about its possible impact on development and increased concerns about the safety of daily exposure. This study aims to provide additional information about the effects of zebrafish early-life exposure to TCC on eye development and visual function. Zebrafish embryos were exposed to two concentrations of TCC (5 and 50 μg/L) for 4 days. TCC-mediated toxicity was assessed in larvae at the end of exposure and in the long term (20 days post fertilization; dpf), through different biological end-points. The experiments showed that TCC exposure influences the retinal architecture. In 4 dpf treated larvae, we found a less organized ciliary marginal zone, a decrease in the inner nuclear and inner plexiform layers, and a decrease in the retinal ganglion cell layer. Photoreceptor and inner plexiform layers showed an increase in 20 dpf larvae at lower and both concentrations, respectively. The expression levels of two genes involved in eye development (mitfb and pax6a) were both decreased at the concentration of 5 μg/L in 4 dpf larvae, and an increase in mitfb was observed in 5 μg/L-exposed 20 dpf larvae. Interestingly, 20 dpf larvae failed to discriminate between visual stimuli, demonstrating notable visual perception impairments due to compound. The results prompt us to hypothesize that early-life exposure to TCC may have severe and potentially long-term effect on zebrafish visual function.

Personal Care Products as a Contributing Factor to Antimicrobial Resistance: Current State and Novel Approach to Investigation

Antimicrobial resistance (AMR) is one of the world's industrialized nations' biggest issues. It has a significant influence on the ecosystem and negatively affects human health. The overuse of antibiotics in the healthcare and agri-food industries has historically been defined as a leading factor, although the use of antimicrobial-containing personal care products plays a significant role in the spread of AMR. Lotions, creams, shampoos, soaps, shower gels, toothpaste, fragrances, and other items are used for everyday grooming and hygiene. However, in addition to the primary ingredients, additives are included to help preserve the product by lowering its microbial load and provide disinfection properties. These same substances are released into the environment, escaping traditional wastewater treatment methods and remaining in ecosystems where they contact microbial communities and promote the spread of resistance. The study of antimicrobial compounds, which are often solely researched from a toxicological point of view, must be resumed considering the recent discoveries, to highlight their contribution to AMR. Parabens, triclocarban, and triclosan are among the most worrying chemicals. To investigate this issue, more effective models must be chosen. Among them, zebrafish is a crucial study system because it allows for the assessment of both the risks associated with exposure to these substances as well as environmental monitoring. Furthermore, artificial intelligence-based computer systems are useful in simplifying the handling of antibiotic resistance data and speeding up drug discovery processes.

Toxicity of methylparaben and its chlorinated derivatives to Allium cepa L. and Eisenia fetida Sav

Methylparaben, chloro-methylparaben, and dichloro-methylparaben were evaluated in Allium cepa at 5, 10, 50, and 100 μg/L and in Eisenia fetida at 10 and 100 μg/L. In A. cepa roots, 100 μg/L methylparaben and 50 and 100 μg/L chlorinated methylparabens reduced cell proliferation, caused cellular changes, and reduced cell viability in meristems, which caused a reduction in root growth. Furthermore, they caused drastic inhibition of catalase, ascorbate peroxidase, and superoxide dismutase; activated guaiacol peroxidase and promoted lipid peroxidation in meristematic root cells. In earthworms, after 14 days exposure to the three compounds, there were no deaths, and catalase, ascorbate peroxidase, and superoxide dismutase were not inhibited. However, guaiacol peroxidase activity and lipid peroxidation were observed in animals exposed to dichloro-methylparaben. Soils with dichloro-methylparaben also caused the escape of earthworms. It is inferred that the recurrent contamination of soils with these methylparabens, with emphasis on chlorinated derivatives, can negatively impact different species that depend directly or indirectly on soil to survive.

Pesticides and Parabens Contaminating Aquatic Environment: Acute and Sub-Chronic Toxicity towards Early-Life Stages of Freshwater Fish and Amphibians

Pesticides and personal care products are two very important groups of contaminants posing a threat to the aquatic environment and the organisms living in it.. Therefore, this study aimed to describe the effects of widely used pesticides and parabens on aquatic non-target biota such as fish (using model organisms Danio rerio and Cyprinus carpio) and amphibians (using model organism Xenopus laevis) using a wide range of endpoints. The first part of the experiment was focused on the embryonal toxicity of three widely used pesticides (metazachlor, prochloraz, and 4-chloro-2-methyl phenoxy acetic acid) and three parabens (methylparaben, propylparaben, and butylparaben) with D. rerio, C. carpio, and X. laevis embryos. An emphasis was placed on using mostly sub-lethal concentrations that are partially relevant to the environmental concentrations of the substances studied. In the second part of the study, an embryo-larval toxicity test with C. carpio was carried out with prochloraz using concentrations 0.1, 1, 10, 100, and 1000 µg/L. The results of both parts of the study show that even the low, environmentally relevant concentrations of the chemicals tested are often able to affect the expression of genes that play either a prominent role in detoxification and sex hormone production or indicate cell stress or, in case of prochloraz, to induce genotoxicity.

Comprehensive assessment of estrogenic activities of parabens by in silico approach and in vitro assays

Parabens are ubiquitous pollutants in the environment and humans due to their wide applications in food, pharmaceuticals, and personal care products. Although the estrogenic activity of some parabens has been confirmed, the underlying mechanisms and the structure-estrogenic activity relationship are still largely unclear. Here, we systematically used in silico and in vitro approaches to investigate the estrogenic potency of typical parabens, including methyl-, ethyl-, propyl-, iso-propyl-, butyl-, iso-butyl- and benzyl-paraben. Molecular dynamics simulations and binding free energy calculations were combined to investigate the atomic-level mechanism of paraben binding to estrogen receptors (ERs). Computational analysis showed that ER were the targets of tested parabens and kept a stable agonist conformation. The calculated total binding free energies suggested that van der Waals interactions were the major driving forces for paraben-ER interaction and correlated with the structure of paraben side chains. In in vitro assays, paraben with an aromatic side chain, benzyl-paraben, showed the strongest estrogenic activity at 0.01 μM and the EC₅₀ at 0.796 ± 0.307 μM, on par with levels commonly detected in human organs. Among tested parabens with an alkyl side chain, the estrogenicity increased as the side chain length increased from 1 to 4, but no significant difference appeared between parabens with isomeric alkyl side chains (propyl- vs isopropyl and butyl- vs iso-butylparaben). The estrogenic activity of parabens was significantly related to the calculated binding energies (R² = 0.94, p = 0.0012), depending on the side chains of parabens. Our findings provide a significant mechanism for parabens to disrupt estrogenic function and considerations for structural optimization from the perspective of environmental protection.

Assessment of Thyroid Endocrine Disruption Effects of Parabens Using In Vivo, In Vitro, and In Silico Approaches

The extensive applications of parabens in foods, drugs, and cosmetics cause inevitable exposure to humans. Revealing the developmental toxicity of parabens is of utmost importance regarding their safety evaluation. In this study, the effects of four commonly used parabens, including methyl paraben (20 ∼ 200 μM), ethyl paraben (20 ∼ 100 μM), propyl paraben (5 ∼ 20 μM), and butyl paraben (BuP, 2 ∼ 10 μM), were investigated on the early development of zebrafish embryos and larvae. The underlying mechanisms were explored from the aspect of their disturbance in the thyroid endocrine system using in vivo, in vitro, and in silico assays. Paraben exposure caused deleterious effects on the early development of zebrafish, with BuP displaying the highest toxicity among all, resulting in the exposure concentration-related mortality, decreased hatching rate, reduced body length, lowered heart rate, and the incidence of malformation. Further investigation showed that paraben exposure reduced thyroid hormone levels and disturbed the transcriptional expressions of the target genes in the hypothalamic-pituitary-thyroid axis. Molecular docking analysis combined with in vitro GH3 cell proliferation assay testified that all test parabens exhibited thyroid receptor agonistic activities. The findings confirmed the developmental toxicity of the test parabens and their thyroid endocrine disruption effects, providing substantial evidence on the safety control of paraben-based preservatives.

In vitro antibacterial and anti-inflammatory effects of Anacardium occidentale L. extracts and their toxicity on PBMCs and zebrafish embryos

This study evaluated the in vitro antimicrobial and immunomodulatory action of crude extracts from Anacardium occidentale L. (cashew tree) leaves and bark, and to determine their toxicity to peripheral-blood mononuclear cells (PBMCs) and to zebrafish embryos and larvae. Chemical analysis of extracts was performed by proton nuclear magnetic resonance (¹H-NMR). The antibacterial activity was evaluated against selected bacteria strains by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Cytotoxicity of the extracts was assessed using resazurin method, while the effect on production of ROS by PMN leukocytes was measured by luminol. Embryotoxicity to zebrafish was assessed using the fish embryo acute toxicity test (FET) and quantification of toxicity marker enzymes (AChE, LDH, and GST). ¹H-NMR results showed anacardic acid as the main component of the extracts. All bacterial species tested were sensitive to the extracts, with MICs ranging from 312.5 to 10,000 μg/mL. Streptococcus mutans and Escherichia coli were the most susceptible species. The extracts promoted cell viability above 75% at concentrations from 1.25 to 80 μg/mL. Both extracts reduced zymosan-induced ROS (p < 0.05) at concentrations of 1, 8, and 80 μg/mL compared to the control. In vivo, there were embryotoxic effects in zebrafish embryos exposed to both extracts through the presence of lethal and sublethal endpoints. The samples also acted by inhibiting the activities of biomarker enzymes. The A. occidentale L. bark and leaf extracts showed antimicrobial potential and modulated ROS production in vitro, but these also showed embryotoxic effects to zebrafish.

Parental risk factors for congenital diaphragmatic hernia - a large German case-control study

Background

Evidence for periconceptional or prenatal environmental risk factors for the development of congenital diaphragmatic hernia (CDH) is still scarce. Here, in a case-control study we investigated potential environmental risk factors in 199 CDH patients compared to 597 healthy control newborns.

Methods

The following data was collected: time of conception and birth, maternal BMI, parental risk factors such as smoking, alcohol or drug intake, use of hairspray, contact to animals and parental chronic diseases. CDH patients were born between 2001 and 2019, all healthy control newborns were born in 2011. Patients and control newborns were matched in the ratio of three to one.

Results

Presence of CDH was significantly associated with maternal periconceptional alcohol intake (odds ratio = 1.639, 95% confidence interval 1.101–2.440, p = 0.015) and maternal periconceptional use of hairspray (odds ratio = 2.072, 95% confidence interval 1.330–3.229, p = 0.001).

Conclusion

Our study suggests an association between CDH and periconceptional maternal alcohol intake and periconceptional maternal use of hairspray. Besides the identification of novel and confirmation of previously described parental risk factors, our study underlines the multifactorial background of isolated CDH.

Behavioural effects of early-life exposure to parabens in zebrafish larvae

Parabens are classified as endocrine disrupting chemicals due to their ability to activate several nuclear receptors causing changes in hormones-dependent signalling pathways. Central nervous system of developing organisms is particularly vulnerable to changes in hormonal pathways, which could lead to altered brain function, abnormal behaviour and even diseases later in life. The aim of the present study was to investigate the effects of exposure to butylparaben (BuP), ethylparaben (EtP) and methylparaben (MeP) during early development on nervous system using zebrafish larvae's behavioural models. Zebrafish were exposed until 4 days post fertilization (dpf) to three concentrations of each paraben chosen considering the environmentally realistic concentrations of human exposure and the benchmark-dose lower bound calculated for zebrafish larvae (BuP: 5, 50 and 500 μg/L; EtP: 50, 500 and 5000 μg/L; MeP: 100, 1000 and 10,000 μg/L). Activity in novel and in familiar environment, thigmotaxis, visual startle response and photic synchronization of the behavioural circadian rhythms were analysed at 4, 5 and 6 dpf. Zebrafish larvae exposed to BuP 500 μg/L and EtP 5000 μg/L revealed increased anxiety-like behaviour in novel environment. Larvae treated with 500 μg/L of BuP showed reduced activity in familiar and marginally in unfamiliar environment, and larvae exposed to 5000 μg/L of EtP exhibited hyperactivity in familiar environment. Parabens exposure did not influence the visual startle response and the photic synchronization of circadian rhythms in zebrafish larvae. This research highlighted as the exposure to parabens has the potential to interfere with behavioural development of zebrafish.