Polluted water from a storage dam (Villa Victoria, méxico) induces oxidative damage, AChE activity, embryotoxicity, and behavioral changes in Cyprinus carpio larvae.

The Villa Victoria dam is one of the most important storage reservoirs in Mexico since it distributes water to more than 20 million inhabitants in the Metropolitan Zone of Mexico City. In this dam, the common carp (Cyprinus carpio) is an important food resource for the inhabitants, so the aim of this work was to evaluate the oxidative damage (lipoperoxidation, oxidized proteins, antioxidant enzymes activity and gene expression), AChE, embryotoxicity and behavioral changes in C. carpio embryos and larvae exposed to water from Villa Victoria dam for 24, 48, 72 and 96 h. The embryotoxicity was evaluated trough the General Morphology Score (GMS) and the teratogenic index. Behavioral changes in basal locomotor activity and thigmotaxis were evaluated in a DanioVision, Noldus ™. An increase in lipid and protein oxidation as well as modification of CAT, SOD and GPx enzymatic activity was observed during the exposure times. The GMS indicated a low development in the embryos, the teratogenic index was less than 1, however teratogenic effects as yolk edema, fin malformation, head malformation and scoliosis were observed. In parallel, an increase in AChE activity and gene expression was observed reflecting changes in distance traveled of the basal locomotor activity and thigmotaxis at the sampling points. In conclusion, pollutants in water from Villa Victoria dam caused oxidative damage, changes in SOD, CAT, GPx and AChE activity as well as embryotoxicity and modifications in the behavior of C. carpio larvae. This study demonstrates the need to implement restoration programs for this reservoir since, contamination in the Villa Victoria dam could eventually endanger aquatic life and human health.

Integrated adsorption and biological removal of the emerging contaminants ibuprofen, naproxen, atrazine, diazinon, and carbaryl in a horizontal tubular bioreactor.

Groundwater and surface water bodies may have contaminants from urban, industrial, or agricultural wastewater, including emerging contaminants (ECs) or micropollutants (MPs). Frequently, they are not efficiently removed by microbial action due to their minimal concentration in water and the low microbiota affinity for complex compounds. This work developed a process allowing the adsorption of contaminants and their simultaneous biodegradation using horizontal tubular fixed-bed biofilm reactors (HTR). Each HTR has two zones: an equalizer-aerator of the incoming liquid flow and a fixed bed zone. This zone was packed with a mixed support material consisting of granular bio-activated carbon (Bio-GAC) and porous material that increases the bed permeability, thus decreasing the pressure drop. Five microbial communities were acclimated and immobilized in granular activated carbon (GAC) to obtain different specialized Bio-GAC particles able to remove the micropollutants ibuprofen, naproxen, atrazine, carbaryl, and diazinon. The Bio-GAC particles were transferred to HTRs continuously run in microaerophilia at several MPs loading rates. Under these conditions, the removal efficiencies of MPs, except atrazine and carbaryl, were around 100.

Survival and malformation rate in oocytes and larvae of Cyprinus carpio by exposure to an industrial effluent.

Pharmaceuticals are used for the prevention or treatment of diseases, and due to their manufacturing process they are continuously released to water bodies. One of the pharmacological groups detected in aquatic environments is non-steroidal anti-inflammatory drugs (NSAIDs) at trace concentrations. This study evaluated the survival and malformation rate in oocytes and larvae of Cyprinus carpio (C. carpio) after exposure to different proportions of an industrial effluent. Initially, the industrial effluent was sampled from an NSAID manufacturing plant located in the city of Toluca, State of Mexico, subsequently the physicochemical characterization and determination of the concentration of chemical compounds present were carried out. On the other hand, the lethal concentration 50 (LC50) and the effective concentration 50 (EC50) were calculated to determine the teratogenic index (TI), as well as the alterations to the embryonic development and the teratogenic effects on oocytes and larvae of C. carpio at the following proportions of the industrial effluent: 0.1, 0.3, 0.5, 0.7, 0.9 and 1.1%, following the Test Guideline 236, which describes a Fish Embryo Acute Toxicity test, the exposure times were 12, 24, 48, 72 and 96 h post-fertilization. The contaminants detected were NaClO (2.6 mg L-1) and NSAIDs such as diclofenac, ibuprofen, naproxen and paracetamol in the range of 1.09-2.68 mg L-1. In this study the LC50 was 0.275%, the EC50 0.133% and the TI 2.068. Several malformations were observed in all proportions of the industrial effluent evaluated, however the most severe such as spina bifida and paravertebral hemorrhage were observed at the highest effluent proportion. The industrial effluent evaluated in this study represents a risk for organisms that are in contact with it, since it contains chemical compounds that induce embryotoxic and teratogenic effects as observed in oocytes and larvae of C. carpio.

Geno- and cytotoxicity induced on Cyprinus carpio by aluminum, iron, mercury and mixture thereof.

Metals such as Al, Fe and Hg are used in diverse anthropogenic activities. Their presence in water bodies is due mainly to domestic, agricultural and industrial wastewater discharges and constitutes a hazard for the organisms inhabiting these environments. The present study aimed to evaluate geno- and cytotoxicity induced by Al, Fe, Hg and the mixture of these metals on blood of the common carp Cyprinus carpio. Specimens were exposed to the permissible limits in water for human use and consumption according to the pertinent official Mexican norm [official Mexican norm NOM-127-SSA1-1994] Al (0.2mgL-1), Fe (0.3mgL-1), Hg (0.001mgL-1) and their mixture for 12, 24, 48, 72 and 96h. Biomarkers of genotoxicity (comet assay and micronucleus test) and cytotoxicity (caspase-3 activity and TUNEL assay) were evaluated. Significant increases relative to the control group (p<0.05) were observed in all biomarkers at all exposure times in all test systems; however, damage was greater when the metals were present as a mixture. Furthermore, correlations between metal concentrations and biomarkers of geno- and cytotoxicity were found only at certain exposure times. In conclusion, Al, Fe, Hg and the mixture of these metals induce geno- and cytotoxicity on blood of C. carpio.

Effect of amoxicillin exposure on brain, gill, liver, and kidney of common carp (Cyprinus carpio): The role of amoxicilloic acid.

Amoxicillin (AMX) is one of the most commonly prescribed antibiotics around the world due to its broad-spectrum activity against different bacterial strains as well as its use as a growth promoter in animal husbandry. Although residues of this antibacterial agent have been found in water bodies in diverse countries, there is not enough information on its potential toxicity to aquatic organisms such as the common carp Cyprinus carpio. This study aimed to evaluate AMX-induced oxidative stress in brain, gill, liver and kidney of C. carpio. Carp were exposed to three different concentrations of AMX (10 ng/L, 10 µg/L, 10 mg/L) for 12, 24, 48, 72, and 96 h, and the following biomarkers were evaluated: lipid peroxidation (LPX), hydroperoxide content (HPC), protein carbonyl content (PCC) and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Amoxicillin and its main degradation product amoxicilloic acid (AMA) were determined by high performance liquid chromatography coupled with electrochemical detection and UV detection (HPLC-EC-UV). Significant increases in LPX, HPC, and PCC (P < 0.05) were found in all study organs, particularly kidney, as well as significant changes in antioxidant enzymes activity. Amoxicilloic acid in water is concluded to induce oxidative stress in C. carpio, this damage being highest in kidney. The biomarkers used are effective for the assessment of the environmental impact of this agent on aquatic species. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1102-1120, 2017.

Cyto-genotoxicity and oxidative stress in common carp (Cyprinus carpio) exposed to a mixture of ibuprofen and diclofenac.

Thirty million people worldwide consume each day nonsteroidal anti-inflammatory drugs (NSAIDs), a heterogeneous group of pharmaceuticals used for its analgesic, antipyretic, and anti-inflammatory properties. Recent studies report high NSAID concentrations in wastewater treatment plant effluents, in surface, ground, and drinking water, and in sediments. NSAIDs are also known to induce toxicity on aquatic organisms. However, toxicity in natural ecosystems is not usually the result of exposure to a single substance but to a mixture of toxic agents, yet only a few studies have evaluated the toxicity of mixtures. The aim of this study was to evaluate the toxicity induced by diclofenac (DCF), ibuprofen (IBP), and their mixture on a species of commercial interest, the common carp Cyprinus carpio. The median lethal concentration of IBP and DCF was determined, and oxidative stress was evaluated using the following biomarkers: lipid peroxidation and activity of the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase. Cyto-genotoxicity was evaluated by micronucleus test, comet assay, and the specific activity of caspase-3. Results show that DCF, IBP, and a mixture of these pharmaceuticals induced free radical production, oxidative stress and cyto-genotoxicity in tissues of C. carpio. However, a greater effect was elicited by the mixture than by either pharmaceutical alone in some biomarkers evaluated, particularly in gill. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1637-1650, 2017.

Oxidative stress induced in Hyalella azteca by an effluent from a NSAID-manufacturing plant in Mexico.

Production in the pharmaceutical industry has increased and along with it, the amount of wastewater of various characteristics and contaminant concentrations. The main chemicals in these effluents are solvents, detergents, disinfectants-such as sodium hypochlorite (NaClO)-and pharmaceutical products, all of which are potentially ecotoxic. Therefore, this study aimed to evaluate the oxidative stress induced in the amphipod Hyalella azteca by the effluent from a nonsteroidal anti-inflammatory drug (NSAID)-manufacturing plant. The median lethal concentration (72 h-LC50) was determined and H. azteca were exposed to the lowest observed adverse effect level (0.0732 %) for 12, 24, 48 and 72 h, and biomarkers of oxidative stress were evaluated [hydroperoxide content (HPC), lipid peroxidation (LPX), protein carbonyl content (PCC), and the activity of the superoxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)]. Statistically significant increases with respect to the control group (P < 0.05) were observed in HPC, LPX and PCC in H. azteca at all exposure times. Antioxidant enzymes activity SOD, CAT and GPx activity also increased significantly (P < 0.05) with respect to the control group. In conclusion, the industrial effluent analyzed in the present study contains NSAIDs and NaClO, and induces oxidative stress in H. azteca.

Biomarkers of Cytotoxic, Genotoxic and Apoptotic Effects in Cyprinus carpio Exposed to Complex Mixture of Contaminants from Hospital Effluents.

Hospital wastewater is an important source of emerging contaminants. Recent studies emphasize the importance of assessing the effects of mixtures of contaminants rather than environmental risk of their individual components, as well as the determination of intrinsic toxicity of wastewater. Mixtures of pollutants has possible interactions that have notable environmental side effects. The aim of this study is an attempt to characterize biomarkers in Cyprinus carpio related to the exposure to a complex mixture of contaminants found in hospital wastewater. Results of a particular hospital effluent show the presence of traces of heavy metals, high chlorine concentration and emerging contaminants such as non-steroidal anti-inflammatory drugs. The LC50 was of 5.49 % at 96 h. The cytotoxic, genotoxic and apoptotic biomarkers increase when fishes were exposed to wastewater (1/10 CL50) from hospital wastewater. This study emphasizes the importance of identifying and quantifying the effects of contaminants as pharmaceuticals, disinfectants and surfactants in order to design and implement an ecotoxicological plan.

Short and long-term exposure to diclofenac alter oxidative stress status in common carp Cyprinus carpio.

Diclofenac (DCF) has been detected in significant amounts in municipal treated wastewater effluent. Diverse studies report that trace concentrations of DCF may induce toxic effects on different aquatic organisms as well as developmental, reproductive and renal damage. This study aimed to determine whether short and long-term exposure to DCF alter the oxidative stress (OS) status in blood, muscle, gills, brain and liver of common carp Cyprinus carpio. The median lethal concentration of DCF at 96 h (96-h LC50) and subsequently the lowest observed adverse effect level were determined. Carp were exposed (short and long-term) to the latter value for different exposure times (4 and 24 days) and the following biomarkers were evaluated in gill, brain, liver and blood: hydroperoxides content (HPC), lipid peroxidation (LPX), protein carbonyl content (PCC) and the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Also, the DCF was determined by LC-MS/MS. Significant increases in HPC, LPX and PCC were observed respect to control (P < 0.05) particularly in blood, muscle, gill, brain and liver. SOD, CAT and GPx activity also increased in these organs, with respect to controls (P < 0.05). DCF concentrations decreased and increased in water system and carp, respectively. Cyprinus carpio exposed to DCF was affected in OS status during the initial days of the study (at 4 days), exhibiting an increased response at 24 days in blood and liver. In contrast, a decrease was observed in muscle, gills and brain at 24 days with respect to 4 days. In conclusion, DCF induces OS on blood, muscle, gills, brain and liver in the carp C. carpio in short and long-term exposure. The biomarkers employed in this study are useful in the assessment of the environmental impact of this agent on aquatic species.

Oxidative stress in Cyprinus carpio induced by hospital wastewater in Mexico.

The very wide range of activities performed in hospitals (care, diagnosis, hygiene, maintenance, research) require the use of a large variety of potentially ecotoxic substances such as surfactants, metals, disinfectants and pharmaceuticals. This study aimed to determine oxidative stress in the common carp Cyprinus carpio induced by hospital wastewater (HWW) in Mexico. The median lethal concentration (LC50) and subsequently the lowest observed adverse effect level were determined. Carp were exposed to the latter value (0.5 %) for 24, 48, 72 and 96 h, and the following biomarkers were evaluated in gill, brain, liver and blood: hydroperoxide content (HPC), malondialdehyde (MDA) content, protein carbonyl content (PCC) and activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Significant increases in HPC, MDA content and PCC were observed in exposed specimens, particularly in gill, liver and brain. SOD and CAT activity also increased in liver and brain. In conclusion, this particular HWW induces oxidative stress on C. carpio, this damage being most evident in gill, liver and brain.

Genotoxic response and oxidative stress induced by diclofenac, ibuprofen and naproxen in Daphnia magna.

CONTEXT: Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used pharmaceuticals in Mexico, but there is not proper regulation on the sale, use and disposal. These drugs can enter water bodies by diverse pathways, attaining significant concentrations and inducing damage on hydrobionts. OBJECTIVE: To evaluate the oxidative stress and consequent damage to genetic material induced by DCF, IBP and NPX on Daphnia magna. METHODS: The acute toxicity assays were performed to 48-h by nonsteroidal anti-inflammatory drugs evaluated. A sublethal assay were done after 48 h of exposure to DCF, IBP and NPX added to water with the concentration equivalent to the lowest observed adverse effect level (LOAEL), 9.7 mg/L for DCF, 2.9 mg/L for IBP and 0.017 mg/L for NPX. The DNA damage (comet assay) was evaluated at 12, 48 and 96 h. The oxidative biomarkers were evaluated: lipid peroxidation; protein carbonyl content; activity of the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase. RESULTS: D. magna exposed to DCF, IBP and NPX showed a significant increase (p < 0.05) with respect to controls in LPX. PCC was increased in IBP exposure. SOD and CAT activity were increased by exposure to IBP and NPX. GPX shows a significant increase with respect to control in IBP and DCF exposure and significant decrease by NPX exposure. DNA damage was observed in 48 and 96 h. DISCUSSION AND CONCLUSION: DCF, IBP and NPX were responsible of alterations in biochemical biomarkers evaluated and DNA damage.

Metals and nonsteroidal anti-inflammatory pharmaceuticals drugs present in water from Madín Reservoir (Mexico) induce oxidative stress in gill, blood, and muscle of common carp (Cyprinus carpio).

Many toxic xenobiotics that enter the aquatic environment exert their effects through redox cycling. Oxidative stress, which incorporates both oxidative damage and antioxidant defenses, is a common effect induced in organisms exposed to xenobiotics in their environment. The results of the present study aimed to determine the oxidative stress induced in the common carp Cyprinus carpio by contaminants [metals and nonsteroidal anti-inflammatory drugs (NSAIDs)] present in Madín Reservoir. Five sampling stations (SSs), considered to have the most problems due to discharges, were selected. Carp were exposed to water from each SS for 96 h, and the following biomarkers were evaluated in gill, blood, and muscle: hydroperoxide content, lipid peroxidation, protein carbonyl content, and the activity of antioxidant enzymes superoxide dismutase and catalase. Results show that contaminants (metals and NSAIDs) present in water from the different SSs induce oxidative stress. Thus, water in this reservoir is contaminated with xenobiotics that are hazardous to C. carpio, a species consumed by the local human population.

Binary mixtures of diclofenac with paracetamol, ibuprofen, naproxen, and acetylsalicylic acid and these pharmaceuticals in isolated form induce oxidative stress on Hyalella azteca.

Toxicity in natural ecosystems is usually not due to exposure to a single substance, but is rather the result of exposure to mixtures of toxic substances. Knowing the effects of contaminants as a mixture compared to their effects in isolated form is therefore important. This study aimed to evaluate the oxidative stress induced by binary mixtures of diclofenac with paracetamol, ibuprofen, naproxen, and acetylsalicylic acid and by these nonsteroidal anti-inflammatory drugs (NSAIDs) in isolated form, using Hyalella azteca as a bioindicator. The median lethal concentration (LC50) and the lowest observed adverse effect level (LOAEL) of each NSAID were obtained. Amphipods were exposed for 72 h to the latter value in isolated form and as binary mixtures. The following biomarkers were evaluated: lipid peroxidation (LPX), protein carbonyl content (PCC), and activity of the antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Significant increases in LPX and PCC with respect to the control group (p ≤ 0.05) were induced by NSAIDs both in isolated form and as binary mixtures. Changes in SOD, CAT, and GPx activity likewise occurred with NSAIDs in isolated form and as binary mixtures. In conclusion, NSAIDs used in this study induce oxidative stress on H. azteca both in isolated form and as binary mixtures, and the interactions occurring between these pharmaceuticals are probably antagonistic in type.

Assessing the impact of COVID-19 era drug combinations on hepatic functionality: A thorough investigation in adult Danio rerio.

Current and thorough information on the ecotoxicological consequences of pharmaceuticals is accessible globally. However, there remains a substantial gap in knowledge concerning the potentially toxic effects of COVID-19 used drugs, individually and combined, on aquatic organisms. Given the factors above, our investigation assumes pivotal importance in elucidating whether or not paracetamol, dexamethasone, metformin, and their tertiary mixtures might prompt histological impairment, oxidative stress, and apoptosis in the liver of zebrafish. The findings indicated that all treatments, except paracetamol, augmented the antioxidant activity of superoxide dismutase (SOD) and catalase (CAD), along with elevating the levels of oxidative biomarkers such as lipid peroxidation (LPX), hydroperoxides (HPC), and protein carbonyl content (PCC). Paracetamol prompted a reduction in the activities SOD and CAT and exhibited the most pronounced toxic response when compared to the other treatments. The gene expression patterns paralleled those of oxidative stress, with all treatments demonstrating overexpression of bax, bcl2, and p53. The above suggested a probable apoptotic response in the liver of the fish. Nevertheless, our histological examinations revealed that none of the treatments induced an apoptotic or inflammatory response in the hepatocytes. Instead, the observed tissue alterations encompassed leukocyte infiltration, sinusoidal dilatation, pyknosis, fatty degeneration, diffuse congestion, and vacuolization. In summary, the hepatic toxicity elicited by COVID-19 drugs in zebrafish was less pronounced than anticipated. This attenuation could be attributed to metformin's antioxidant and hormetic effects.

Eco-endocrinological dynamics: Unraveling dexamethasone's influence on the interrenal axis in juvenile carp Cyprinus carpio.

This study delves into the eco-endocrinological dynamics concerning the impact of dexamethasone (DXE) on the interrenal axis in juvenile carp, Cyprinus carpio. Through a comprehensive analysis, we investigated the effects of DXE exposure on oxidative stress, biochemical biomarkers, gene expression, and bioaccumulation within the interrenal axis. Results revealed a concentration-dependent escalation of cellular oxidation biomarkers, including 1) hydroperoxides content (HPC), 2) lipid peroxidation level (LPX), and 3) protein carbonyl content (PCC), indicative of heightened oxidative stress. Concurrently, the activity of critical antioxidant enzymes, superoxide dismutase (SOD), and catalase (CAT), significantly increased, underscoring the organism's response to oxidative insult. Notable alterations were observed in biochemical biomarkers, particularly Gamma-glutamyl-transpeptidase (GGT) and alkaline phosphatase (ALP) activity, with GGT displaying a significant decrease with increasing DXE concentrations. Gene expression analysis revealed a significant upregulation of stress and inflammation response genes, as well as those associated with sensitivity to superoxide ion presence and calcium signaling, in response to DXE exposure. Furthermore, DXE demonstrated a concentration-dependent presence in interrenal tissue, with consistent bioconcentration factors observed across all concentrations tested. These findings shed light on the physiological and molecular responses of juvenile carp to DXE exposure, emphasizing the potential ecological implications of DXE contamination in aquatic environments. Understanding these dynamics is crucial for assessing the environmental impact of glucocorticoid pollutants and developing effective management strategies to mitigate their adverse effects on aquatic ecosystems.

Diclofenac-induced oxidative stress in brain, liver, gill and blood of common carp (Cyprinus carpio).

Due to its analgesic properties, diclofenac (DCF) is one of the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs). While residue from this pharmaceutical agent has been found in diverse water bodies in various countries, there is not enough information of its potential toxicity on aquatic organisms, particularly in species which are economically valuable due to their high consumption by humans, such as the common carp Cyprinus carpio. This study aimed to evaluate potential DCF-induced oxidative stress in brain, liver, gill and blood of C. carpio. The median lethal concentration of DCF at 96h (96-h LC50) was determined and used to establish the concentration equivalent to the lowest observed adverse effect level (LOAEL). Carp specimens were exposed to this concentration for different exposure times (12, 24, 48, 72 and 96h) and the following biomarkers were evaluated: lipid peroxidation (LPX) and the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Also, the DCF and 4-hydroxy DCF was determined by LC-MS/MS. Results show a statistically significant LPX increase (P<0.05) in liver and gill mainly as well as significant changes in the activity of the antioxidant enzymes evaluated in these organs, with respect to controls (P<0.05). The DCF concentrations decreased in water system and increased in the carp. The DCF biotransformation to 4-hydroxy DCF was observed to 12h. The pharmaceutical agent DCF is concluded to induce oxidative stress on the common carp C. carpio, with the highest incidence of oxidative damage occurring in liver and gill. Furthermore, the biomarkers employed in this study are useful in the assessment of the environmental impact of this agent on aquatic species.

The relationship of cytotoxic and genotoxic damage with blood aluminum levels and oxidative stress induced by this metal in common carp (Cyprinus carpio) erythrocytes.

Aluminum is one of the most abundant elements in nature and is used in diverse industrial processes. As a result, it contaminates aquatic ecosystems, inducing damage on associated biota. In fish, it has been observed to induce hypoxia, hypercapnia, metabolic acidosis and respiratory arrest. Although there is little information on Al-induced cytotoxicity and DNA damage, this type of studies are essential in order to identify the mechanisms of action of this metal. The cytotoxic and genotoxic effects induced by Al on common carp (Cyprinus carpio) erythrocytes were determined in specimens exposed to 0.05, 120 and 239mgAlL(-1) in static exposure systems. Blood samples were taken at 12, 24, 48, 72 and 96h, erythrocytes were separated, and the following were evaluated: frequency of micronuclei and frequency of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells, blood Al levels, lipid peroxidation, protein carbonyl content, and activity of the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase. The results show that tested aluminum concentrations produces oxidative stress (increase in lipid peroxidation degree and oxidized proteins content, as well as decrease in antioxidant enzymes activity) and induced higher frequencies of micronuclei and TUNEL-positive cells, so this metal can be considered as a cytotoxic and genotoxic agent for erythrocytes of common carp.

Realistic concentrations of Bisphenol-A trigger a neurotoxic response in the brain of zebrafish: Oxidative stress, behavioral impairment, acetylcholinesterase inhibition, and gene expression disruption.

Bisphenol A (BPA) is a micro-pollutant found in various environmental matrices at concentrations as low as ng/L. Recent studies have shown that this compound can cause oxidative damage and neurotoxic effects in aquatic organisms. However, there is a lack of research investigating the effects of BPA at environmentally relevant concentrations. Therefore, this study aimed to assess the neurotoxic effects of acute BPA exposure (96 h) at environmentally relevant concentrations (220, 1180, and 1500 ng/L) in adult zebrafish (Danio rerio). The Novel Tank trial was used to evaluate fish swimming behavior, and our results indicate that exposure to 1500 ng/L of BPA reduced the total distance traveled and increased freezing time. Furthermore, the evaluation of biomarkers in the zebrafish brain revealed that BPA exposure led to the production of reactive oxygen species and increased acetylcholinesterase activity. Gene expression analysis also indicated the overexpression of mbp, α1-tubulin, and manf in the zebrafish brain. Based on our findings, we concluded that environmentally relevant concentrations of BPA can cause anxiety-like behavior and neurotoxic effects in adult zebrafish.

Oxidative stress as regulator of neuronal impairment after exposure to hospital effluents in Danio rerio.

The variety of activities carried out within hospitals results in their final discharges being considered hotspots for the emission of emerging pollutants. Hospital effluents contain different substances capable of altering the health of ecosystems and biota, furthermore, little research has been done to elucidate the adverse effects of these anthropogenic matrices. Taking this into account, herein we aimed to establish whether exposure to different proportions (2 %, 2.5 %, 3 %, and 3.5 %) of hospital effluent treated by hospital wastewater treatment plant (HWWTP) can induce oxidative stress, behavioral alterations, neurotoxicity, and disruption of gene expression in Danio rerio brain. Our results demonstrate that the hospital effluent under-study induces an anxiety-like state and alters swimming behavior, as fish exhibited increased freezing episodes, erratic movements and traveled less distance than the control group. In addition, after exposure we observed a meaningful rise in biomarkers related to oxidative damage, such as protein carbonyl content (PCC), lipoperoxidation level (LPX), hydroperoxide content (HPC), as well as an increase in enzyme antioxidant activities of catalase (CAT), and superoxide dismutase (SOD) upon short-term exposure. Moreover, we discovered an inhibition of acetylcholinesterase (AChE) activity in a hospital effluent proportion-dependent manner. Regarding gene expression, a significant disruption of genes related to antioxidant response (cat, sod, nrf2), apoptosis (casp6, bax, casp9), and detoxification (cyp1a1) was observed. In conclusion, our outcomes suggest that hospital effluents enhance the emergence of oxidative molecules, and promote a highly oxidative environment at the neuronal level that favors the inhibition of AChE activity, which consequently explains the anxiety-like behavior observed in D. rerio adults. Lastly, our research sheds light on possible toxicodynamic mechanism by which these anthropogenic matrices may trigger damage in D. rerio brain.

Short-term exposure to dexamethasone at environmentally relevant concentrations impairs embryonic development in Cyprinus carpio: Bioconcentration and alteration of oxidative stress-related gene expression patterns.

In recent years and as a result of the Covid-19 pandemic, the consumption of dexamethasone (DXE) has increased. This favors that this corticosteroid is highly released in aquatic environments, generating deleterious effects in aquatic organisms. The information on the toxic effects of DXE in the environment is still limited. Thus, the objective of this work was to determine whether DXE at short-term exposure can cause alterations to embryonic development and alteration of oxidative stress-related gene expression patterns in Cyprinus carpio. For this purpose, common carp embryos (2 hpf) were exposed to realistic concentrations of DXE until 96 hpf. Alterations to embryonic development were evaluated at 12, 24, 48, 72 and 96 hpf. In addition, oxidative stress in carp embryos at 72 and 96 hpf was evaluated by cellular oxidation biomarkers (lipoperoxidation level, hydroperoxide and carbonyl protein content) and antioxidant enzymes activities (superoxide dismutase and catalase). Oxidative stress-related gene expression (sod, cat and gpx1) was also evaluated. Our results showed that DXE concentrations above 35 ng/L are capable of producing alterations to embryonic development in 50 % of the embryo population. Furthermore, DXE was able to induce alterations such as scoliosis, hypopigmentation, craniofacial malformations, pericardial edema and growth retardation, leading to the death of half of the population at 50 ng/L of DXE. Concerning oxidative stress, the results demonstrated that DXE induce oxidative damage on the embryos of C. carpio. In conclusion, DXE is capable of altering embryonic development and generating oxidative stress in common carp C. carpio.