Single and combined effects of carbamazepine and copper on nervous and antioxidant systems of zebrafish (Danio rerio)

Acute exposure to environmentally relevant concentrations of pharmaceutical pollutants induces neurobehavioral toxicity in zebrafish (Danio rerio)

Pharmaceutical waste from point and non-point sources enters, persists, or disseminates in the environment and is known as environmentally persistent pharmaceutical pollutants. Understanding the impacts of pharmaceutical pollutants on the environment and health is essential. This study investigates the behavioral impacts of pharmaceutical pollutants on aquatic organisms and delineates the possible nexus of oxidative stress. The male zebrafish were exposed to four major representative pharmaceutical pollutants, viz., acetaminophen, carbamazepine, metformin, and trimethoprim at environmentally relevant concentrations individually as well as in a mixture for seven days. Substantial alterations in social interaction, aggressive nature, novel tank exploration, and light and dark zone preferences were recorded and the degree varied to different pharmaceutical pollutants. The activity of oxidative stress markers, superoxide dismutase, glutathione-S-transferase, and catalase, was found to be suppressed to 66-20%, 42-25%, and 59-20% respectively with the elevated malondialdehyde generation (180-260%) compared to control. The activity level of acetylcholine esterase was found to be increased to 200-500% across all treatment groups. Despite the synergistic impacts of pharmaceutical pollutants on the whole system that could not be ascertained, this comprehensive study highlights their toxicity nature to induce neurobehavioral toxicity in zebrafish through oxidative stress mechanisms and altered cholinergic systems.

Combined effects of polyethylene terephthalate and abamectin on enzymatic activity and histopathology response in juvenile zebrafish (Danio rerio)

One of the most pressing global environmental issues is the widespread abundance and distribution of microplastics (MPs). MPs can act as vectors for other contaminants in the environment making these small plastic particles hazardous for ecosystems. The presence of MPs in aquatic environments may pose threats to aquatic organisms that ingest them. This study examined effects of abamectin (ABM) and polyethylene terephthalate (PET) MP fragments on histopathological and enzymatic biomarkers in zebrafish (Danio rerio). Zebrafish were exposed for 96 h to pristine PET-MPs at concentrations of 5 mg/L and 10 mg/L, ABM alone at 0.006 mg/L, and the same concentration of ABM in the presence of PET-MPs in aquaria. Histopathological analysis revealed tissue content changes in liver and kidney in the presence of ABM individually and in combination with MPs. Results of enzymatic analysis showed that MPs increased the bioavailability and toxicity of pesticides due to inhibition of catalase (CAT) and acid phosphatase (ACP) enzymes. However, MPs did not affect the toxicity of ABM for glutathione s-transferase (GST) enzyme. Despite the inhibition of acetylcholinesterase (AChE) in MPs or ABM treatments, and some neurotoxicity, no change in activity of this enzyme and neurotoxicity was observed in the combined MPs and ABM treatments, although toxicity effects of MPs and ABM on zebrafish require more detailed studies.

Reviewing the use of zebrafish for the detection of neurotoxicity induced by chemical mixtures through the analysis of behaviour

The knowledge and assessment of mixtures of chemical pollutants in the aquatic environment is a complex issue that is often challenging to address. In this review, we focused on the use of zebrafish (Danio rerio), a vertebrate widely used in biomedical research, as a model for detecting the effects of chemical mixtures with a focus on behaviour. Our aim was to summarize the current status of the ecotoxicological research in this sector. Specifically, we limited our research to the period between January 2012 and September 2023, including only those works aimed at detecting neurotoxicity through behavioural endpoints, utilizing zebrafish at one or more developmental stages, from egg to adult. Additionally, we gathered the findings for every group of chemicals involved and summarised data from all the works we included. At the end of the screening process 101 papers were considered eligible for inclusion. Results show a growing interest in zebrafish at all life stages for this kind of research in the last decade. Also, a wide variety of different assays, involving different senses, was used in the works we surveyed, with exposures ranging from acute to chronic. In conclusion, the results of this study show the versatility of zebrafish as a model for the detection of mixture toxicity although, for what concerns behavioural analysis, the lack of standardisation of methods and endpoints might still be limiting.

Enrichment and distribution of 3,6-dichlorocarbazole in red crucian carp (Carassius auratus) and its hepatotoxicity

Polyhalogenated carbazoles (PHCZs) are a class of organohalogen compounds where the hydrogen atom on the carbazole ring is replaced by a halogen atom. In recent years, PHCZs have drawn increasing concern due to their persistence, dioxin-like toxicity, bioaccumulation, potential ecological hazards and widespread occurrence in the environment. Current research on the enrichment and depuration of PHCZs in biological tissues and organs is insufficient, and the liver toxicity is unclear. Herein, to understand the enrichment and elimination of 3,6-DCCZ in fish tissues and organs as well as the hepatotoxicity, we exposed the red crucian carp to 20 and 100 μg/L of 3,6-DCCZ for 20 days followed by a depuration period of 10 days. The 3,6-DCCZ enrichment in each organ tissue was classified from high to low: brain > liver, intestine, gill > muscle. For depuration, 3,6-DCCZ was quickly excreted in the various organs of the red crucian carp; however, the liver depuration was slow, with the concentration of 3,6-DCCZ was maintained at 0.25-0.35 μg/g. 3,6-DCCZ exposure at both tested concentrations induced oxidative stress in red crucian carp, causing lipid peroxidation and DNA damage, as well as some histopathological changes in the liver, such as cell vacuolization, nucleus pyknosis, nucleus pleomorphism, no nucleus areas. Additionally, the 3,6-DCCZ exposure at higher concentration (100 μg/L) caused more serious damage and abnormal lipid metabolism in the red crucian carp liver.

Copper and cadmium, isolated and in the mixture, impact the Neotropical freshwater Calanoida copepod Notodiaptomus iheringi: A short-term approach with environmental concentrations

Metal discharges in aquatic ecosystems are of concern since they affect different trophic levels, altering the functioning of the aquatic food chain. The metals can interact among them and with other pollutants, resulting in complex mixtures whose effects on biota are unpredictable. The impacts of copper (Cu) and cadmium (Cd), isolated and combined, on the freshwater copepod Notodiaptomus iheringi were assessed in acute and sub-chronic exposures. Species sensitivity distribution (SSD) curves were constructed for both metals. In the acute tests antagonism was observed in mortality, while in sub-chronic, mortality was not affected; however, the eggs produced and percentage of viable eggs were significantly altered. Our data suggest that egg production can be a detoxification route in N. iheringi under Cu and mixture exposure. From the SSD curves, N. iheringi was the most sensitive Brazilian species for Cu and the second most sensitive for Cd.

Exposure to copper induces endoplasmic reticulum (ER) stress-mediated apoptosis in chicken (Gallus gallus) myocardium

Copper (Cu), an omnipresent environmental pollutant, can cause potential harm to the public and ecosystems. In order to study the cardiotoxicity caused by Cu, molecular biology techniques were used to analyze the effect of Cu on ER stress-mediated cardiac apoptosis. In vivo investigation, 240 1-day-old chickens were fed with Cu (11, 110, 220, and 330 mg/kg) diet for 7 weeks. The consequence showed that high-Cu can induce ER stress and apoptosis in heart tissue. The vitro experiments, the Cu treatment for 24 h could provoke ultrastructural damage and upregulate the apoptosis rate. Meanwhile, GRP78, GRP94, eIF2α, ATF6, XBP1, CHOP, Bax, Bak1, Bcl2, Caspase-12 and Caspase-3 genes levels, and GRP78, GRP94 and Caspase-3 proteins levels were increased, which indicated that ER stress and apoptosis in cardiomyocytes. But the mRNA level of Bcl2 were decreased after Cu exposure. Conversely, Cu-induced ER stress-mediated apoptosis can be alleviated by treatment with 4-PBA. These findings generally showed that Cu exposure can contribute to ER stress-mediated apoptosis in chicken myocardium, which clarifies the important mechanism link between ER stress and apoptosis, and provides a new perspective for Cu toxicology.

The occurrence of typical psychotropic drugs in the aquatic environments and their potential toxicity to aquatic organisms - A review

Psychotropic drugs (PDs) and their bioactive metabolites often persist in aquatic environments due to their typical physical properties, which made them resistant to removal by traditional wastewater treatment plants (WWTPs). Consequently, such drugs and/or their metabolites are frequently detected in both aquatic environments and organisms. Even at low concentrations, these drugs can exhibit toxic effects on non-target organisms including bony fish (zebrafish (Danio rerio) and fathead minnows) and bivalves (freshwater mussels and clams). This narrative review focuses on the quintessential representatives of three different categories of PDs-antiepileptics, antidepressants, and antipsychotics. The data regarding their concentrations occurring in the environment, patterns of distribution, the degree of enrichment in various tissues of aquatic organisms, and the toxicological effects on them are summarized. The toxicological assessments of these drugs included the evaluation of their effects on the reproductive, embryonic development, oxidative stress-related, neurobehavioral, and genetic functions in various experimental models. However, the mechanisms underlying the toxicity of PDs to aquatic organisms and their potential health risks to humans remain unclear. Most studies have focused on the effects caused by acute short-term exposure due to limitations in the experimental conditions, thus making it necessary to investigate the chronic toxic effects at concentrations that are in coherence with those occurring in the environment. Additionally, this review aims to raise awareness and stimulate further research efforts by highlighting the gaps in the understanding of the mechanisms behind PD-induced toxicity and potential health risks. Ultimately, the study underscores the importance of developing advanced remediation methods for the removal of PDs in WWTPs and encourages a broader discussion on mitigating their environmental impacts.

Non-steroidal anti-inflammatory drugs caused an outbreak of inflammation and oxidative stress with changes in the gut microbiota in rainbow trout (Oncorhynchus mykiss)

One of the main contributors to pharmaceutical pollution of surface waters are non-steroidal anti-inflammatory drugs (NSAIDs) that contaminate the food chain and affect non-target water species. As there are not many studies focusing on toxic effects of NSAIDs on freshwater fish species and specially effects after dietary exposure, we selected rainbow trout (Oncorhynchus mykiss) as the ideal model to examine the impact of two NSAIDs - diclofenac (DCF) and ibuprofen (IBP). The aim of our study was to test toxicity of environmentally relevant concentrations of these drugs together with exposure doses of 100× higher, including their mixture; and to deepen knowledge about the mechanism of toxicity of these drugs. This study revealed kidneys as the most affected organ with hyalinosis, an increase in oxidative stress markers, and changes in gene expression of heat shock protein 70 to be signs of renal toxicity. Furthermore, hepatotoxicity was confirmed by histopathological analysis (i.e. dystrophy, congestion, and inflammatory cell increase), change in biochemical markers, increase in heat shock protein 70 mRNA, and by oxidative stress analysis. The gills were locally deformed and showed signs of inflammatory processes and necrotic areas. Given the increase in oxidative stress markers and heat shock protein 70 mRNA, severe impairment of oxygen transport may be one of the toxic pathways of NSAIDs. Regarding the microbiota, an overgrowth of Gram-positive species was detected; in particular, significant dysbiosis in the Fusobacteria/Firmicutes ratio was observed. In conclusion, the changes observed after dietary exposure to NSAIDs can influence the organism homeostasis, induce ROS production, potentiate inflammations, and cause gut dysbiosis. Even the environmentally relevant concentration of NSAIDs pose a risk to the aquatic ecosystem as it changed O. mykiss health parameters and we assume that the toxicity of NSAIDs manifests itself at the level of mitochondria and proteins.

Neurotoxicity of singular and combined exposure of Oreochromis niloticus to methomyl and copper sulphate at environmentally relevant levels: Assessment of neurotransmitters, neural stress, oxidative injury and histopathological changes

Aquatic organisms are concomitantly exposed to multiple noxious chemicals that can be discharged into water bodies. We aimed to investigate the single and simultaneous sub-acute exposure to copper and methomyl on juvenile Oreochromis niloticus. Compared to the controls, the outcomes revealed that brain of methomyl-exposed fish displayed significant declines in the activities of SOD, CAT, and GST in addition to higher MDA and lower GSH levels. Methomyl induced notable declines in levels of GABA and acetylcholine esterase in brain and muscle of exposed fish. Noteworthy downregulated gene expression levels of TNF-α, HSP-70 together with upregulated c-fos were evident in brain of fish expose to either of tested compounds. Marked apoptotic changes were observed in fish brain exposed to copper and methomyl indicated by augmented immune expression of caspase-3. Conclusively, the results indicated the possible interaction between both compounds with subsequent toxic effects that differ from their single exposure.

Synergistic effect of chloroquine and copper to the euryhaline rotifer Proales similis

Chloroquine (CQ) has been widely used for many years against malaria and various viral diseases. Its important use and high potential to being persistent make it of particular concern for ecotoxicological studies. Here, we evaluated the toxicity of CQ alone and in combination with copper (Cu) to the euryhaline rotifer Proales similis. All experiments were carried out using chronic toxicity reproductive five-day tests and an application factor (AF) of 0.05, 0.1, 0.3, and 0.5 by multiplying the 24-h LC₅₀ values of CQ (4250 µg/L) and Cu (68 µg/L), which were administered in solution. The rate of population increase (r, d^-1) ranged from 0.50 to 52 (controls); 0.20 to 0.40 (CQ); 0.09 to 0.43 (Cu); and -0.03 to 0.30 (CQ-Cu) and showed significant decrease as the concentration of both chemicals in the medium increased. Almost all tested mixtures induced synergistic effects, mainly as the AF increased. We found that the presence of Cu intensifies the vulnerability of organisms to CQ and vice versa. These results stress the potential hazard that these combined chemicals may have on the aquatic systems. This research suggests that P. similis is sensitive to CQ as other standardized zooplankton species and may serve as a potential test species in the risk assessment of emerging pollutants in marine environments.

Oxidative stress and metal homeostasis alterations in Danio rerio (zebrafish) under single and combined carbamazepine, acetamiprid and cadmium exposures

Contaminants of emerging concern (CEC) are routinely detected in aquatic environments, especially pharmaceuticals, such as carbamazepine (CBZ), and neonicotinoid pesticides, like acetamiprid (ACT). CECs can interact with each other and with other legislated contaminants like Cd, resulting in unknown effects. Most studies evaluate only the effects of single contaminant exposures on aquatic biota. Therefore, the aim of the present study was to assess the effects of both single and combined CBZ, ACT and Cd exposures on zebrafish brain and liver oxidative stress parameters and metal homeostasis. The biomarkers catalase (CAT), glutathione-S-transferase (GST), total thiols (TOT), metallothionein (MT) and malondialdehyde (MDA) and the essential elements Ca, Cu, K, Na, Mg, Mn and Zn were evaluated after 96-hour static exposures. CBZ, ACT and Cd single (brain and liver) and combined (liver) treatments resulted in oxidative effects in both fish organs, also leading to metal (Ca, Mg, K, Mn, Zn and Cu) homeostasis alterations. ACT exposure resulted in the greatest adverse effects in the brain, while CBZ was the cause of major element homeostasis and oxidative stress alterations in the liver. Lower LPO levels were observed in the combined treatments compared to single treatments, suggesting interactions and contaminant effect attenuation. This study is the first to evaluate the initial effects of combined CBZ, ACT and Cd exposures in zebrafish, paving the way for further investigations concerning other biomarkers during longer exposure times.

Effects of carbamazepine in aquatic biota

Carbamazepine (CBZ) is one of the most common pharmaceuticals found in the aquatic environment. Here, we reviewed studies in aquatic animals highlighting that CBZ affected ROS homeostasis but also the neuroendocrine system, cell viability, immunity, reproduction, feeding behavior and growth. Notably, the acetylcholinesterase activity was modified by concentrations of the order of ng L^-1 CBZ. At ≥10 μg L^-1, data pointed that CBZ triggered the production of ROS, modifying the activity of antioxidant enzymes and produced a significant cellular stress at concentrations ≥100 μg L^-1. However, the response appeared species-, organ- and time-dependent, and was impacted by different experimental conditions and the origin of animals. In this context, this review discusses the available data and proposes future research priorities.

Human Drug Pollution in the Aquatic System: The Biochemical Responses of Danio rerio Adults

Simple Summary

The release of medicinal products for human use in the aquatic environment is now a serious problem, and can be fatal for the organisms that live there. Danio rerio is a freshwater fish that provides the possibility to study the effects of these pollutants on the health of aquatic organisms. The results of the various existing scientific studies are scarce and conflicting. Here, we review the scientific studies that have analyzed these effects, highlighting that the impacts of drugs are evident in the biochemical responses of these animals.

Abstract

To date, drug pollution in aquatic systems is an urgent issue, and Danio rerio is a model organism to study the toxicological effects of environmental pollutants. The scientific literature has analyzed the effect of human drug pollution on the biochemical responses in the tissues of D. rerio adults. However, the information is still scarce and conflicting, making it difficult to understand its real impact. The scientific studies are not consistent with each other and, until now, no one has grouped their results to create a baseline of knowledge of the possible impacts. In this review, the analysis of literature data highlights that the effects of drugs on adult zebrafishes depend on various factors, such as the tissue analyzed, the drug concentration and the sex of the individuals. Furthermore, the most influenced biochemical responses concern enzymes (e.g., antioxidants and hydrolase enzymes) and total protein and hormonal levels. Pinpointing the situation to date would improve the understanding of the chronic effects of human drug pollution, helping both to reduce it in the aquatic systems and then to draw up regulations to control this type of pollution.

Mechanism of CuSO4 cytotoxicity in goat erythrocytes after high-level in vitro exposure to isotonic media

Copper (Cu) is a common environmental pollutant in nature. Cu-poisoning can cause liver damage and erythrocytes hemolysis. To evaluate the effect of CuSO₄ poisoning on the morphological and functional characteristics of goat red blood cells. Five 10-14-month-old goats were selected for jugular vein blood sampling to obtain erythrocytes, and then the erythrocytes were processed with different concentrations (0, 10, 20, 30, 40 and 50 μmol/L) of CuSO₄ for 48 h, and 40 μmol/L doses CuSO₄ incubated for different time (12, 24, 36, 48 and 60 h) to process erythrocytes. We observed the changes in erythrocyte morphology through scanning electron microscopy, and detected the antioxidant function and activities of three ATPases. Additionally, biological properties were examined from the perspectives of phospholipids and membrane protein components, permeability fragility, and fluidity in erythrocytes. We found that after CuSO₄ treatment, the antioxidant capacity of erythrocytes decreased, which was manifested as increased MDA content and decreased CuZn-SOD and GSH-Px activities (p < 0.05). In addition, we also found that erythrocyte fluidity decreased, osmotic fragility increased, membrane phospholipid percentage and protein composition changes abnormally, and Na⁺/K⁺-ATPase^, Mg²⁺-ATPase and Ca²⁺-ATPase activities decreased (p < 0.05). From the results, it can be concluded that CuSO₄ exposure causes hemolysis of goat erythrocytes through oxidative stress to the structure and function of erythrocytes, showing a dose-time effect.

Development and Molecular Investigation into the Effects of Carbamazepine Exposure in the Zebrafish (Danio rerio)

Concerns regarding environmental exposures and the impacts of pharmaceuticals on non-target aquatic organisms continue to increase. The antiepileptic drug carbamazepine (CBZ) is often detected as an aquatic contaminant and can disrupt various behaviors of fishes. However, there are few reports which investigate the mechanism of CBZ action in fish. The aim of the current study was to evaluate the effects of CBZ on embryonic development (i.e., hatching rate, heart rate, and body length) and early spontaneous movement. Moreover, we sought to investigate potential mechanisms by focusing on the gamma-aminobutyric acid (GABA) neurotransmitter system in zebrafish 6 days after of exposure. The results show that CBZ exposure did not cause significant effects on embryo development (hatching rate, heart rate, nor body length) at the test concentrations. However, the early spontaneous movement of embryos was inhibited following 10 μg/L CBZ exposure at 28-29 h post-fertilization (hpf). In addition, acetylcholinesterase (AChE) activity and GABA concentrations were increased with exposure, whereas glutamate (Glu) concentrations were decreased in larval zebrafish. Gene expression analysis revealed that GABA and glutamate metabolic pathways in zebrafish larvae were altered following exposure to CBZ. GABA transaminase (abat) and glutamic acid decarboxylase (gad1b) decreased to 100 µg/L, and glutamate receptor, ionotropic, N-methyl D-aspartate 1b (grin1b) as well as the glutamate receptor, ionotropic, α-amino-3hydroxy-5methylisoxazole-4propionic 2b (gria2b) were down-regulated with exposure to 1 µg/L CBZ. Our study suggests that CBZ, which can act as an agonist of the GABA_A receptor in humans, can also induce alterations in the GABAergic system in fish. Overall, this study improves understanding of the neurotoxicity and behavioral toxicity of zebrafish exposed to CBZ and generates data to be used to understand mechanisms of action that may underlie antiepileptic drug exposures.