Oxytocin Enhances Time-Dependent Responses in the Aggressive Zebrafish (Danio rerio).

Autism spectrum disorder (ASD) has become one of the most well-known disorders encountered since early childhood among people. Nowadays, the main concerns are its high prevalence and the lack of proper therapeutic interventions. In this way, the necessity of using animal models that can mimic some of the spectrum symptoms, besides deepening the mechanisms of occurrence, is undeniable. Oxytocin (OT) is often mentioned and linked to producing social domain improvements. The goal of the present study was to determine if different time exposures to OT can trigger distinct behavioral responses in zebrafish, potentially offering insights into autism therapy. To accomplish this goal, zebrafish were exposed to the same dose of OT (33.2 ng/mL OT) for one week but with different time frames, such as: continuous exposure for seven days, fifteen minutes per day for seven days, and every two days for the same amount of time. The behavior of the fish was recorded using the EthoVision XT 11.5 software, and each trial lasted four minutes. Specific parameters for locomotor activity and aggressive behavior were measured. Overall, zebrafish exposure to OT generated several improvements in locomotor activity and aggressive behavior. Moreover, the differences in the exposure period indicated that time is an important factor, showing that continuous exposure to OT was linked with better performance than exposure to the hormone every two days. At the same time, the most variable results were observed in the case of fish exposed every day to OT. Exposure to OT could lead to certain improvements in zebrafish behavior that can be time-sensitive. Nevertheless, further work is needed in order to investigate the mechanisms of action of OT in an ASD context.

Vitamin B12 Ameliorates Pesticide-Induced Sociability Impairment in Zebrafish (Danio rerio): A Prospective Controlled Intervention Study.

Constant exposure to a variety of environmental factors has become increasingly problematic. A variety of illnesses are initiated or aided by the presence of certain perturbing factors. In the case of autism spectrum disorder, the environmental component plays an important part in determining the overall picture. Moreover, the lack of therapies to relieve existing symptoms complicates the fight against this condition. As a result, animal models have been used to make biomedical research easier and more suited for disease investigations. The current study used zebrafish as an animal model to mimic a real-life scenario: acute exposure to an increased dose of pesticides, followed by prospective intervention-based therapy with vitamin B12 (vit. B12). It is known that vit. B12 is involved in brain function nerve tissue, and red blood cell formation. Aside from this, the role of vit. B12 in the redox processes is recognized for its help against free radicals. To investigate the effect of vit. B12, fish were divided into four different groups and exposed to a pesticide mixture (600 µg L-1 fipronil + 600 µg L-1 pyriproxyfen) and 0.24 µg L-1 vit. B12 for 14 days. The impact of the compounds was assessed daily with EthoVision XT 11.5 software for behavioral observations, especially for sociability, quantified by the social interaction test. In addition, at the end of the study, the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) were measured. The results showed significant improvements in locomotor activity parameters and a positive influence of the vitamin on sociability. Regarding the state of oxidative stress, high activity was found for SOD and GPx in the case of vit. B12, while fish exposed to the mixture of pesticides and vit. B12 had a lower level of MDA. In conclusion, the study provides new data about the effect of vit. B12 in zebrafish, highlighting the potential use of vitamin supplementation to maintain and support the function of the organism.

A new approach to explore the correlation between declarative memory and anxiety in animal models of schizophrenia and microplastic pollution.

The discovery of new detrimental effects associated with microplastic pollution is ever-growing and reaching alarming rates worldwide, as it is linked to numerous disorders such as lung diseases, gastrointestinal problems, and cancer. However, a less explored issue is their impact on mental health, more precisely schizophrenia, even though several studies have shown the presence of microplastics in air, water, soil, and even food, thus making them a significant part of our daily dietary intake. It is also well known that declarative memory and anxiety levels are impaired in schizophrenia. However, apart from the novel object recognition test, the possibilities for testing memory in zebrafish are quite limited. For these reasons, we designed a novel memory test based on rewards, a learning period, and zebrafish's natural preference for certain colors. Among the results, our fish preferred the color yellow over red, and we illustrated that ketamine and its combination with methionine provide a robust model that seems to better represent the aspects of schizophrenia in animal models. Moreover, surprisingly, we observed that microplastics (more precisely, polypropylene fibers) ingested by animals through the diet seem to act as a buffer against ketamine toxicity and as an enhancer for methionine exposure. Moreover, according to our results, groups with higher anxiety levels seem to perform better on the memory test.

Current Aspects on the Plastic Nano- and Microparticles Toxicity in Zebrafish-Focus on the Correlation between Oxidative Stress Responses and Neurodevelopment.

Recent reports focusing on the extent of plastic pollution have shown that many types of fibers and polymers can now be found in most marine species. The severe contamination of plastic nano-/microparticles (NPs/MPs) mainly results in immediate negative outcomes, such as organic impairments and tissue damage, as well as long-termed negative effects, such as developmental retardation and defects, chronic inflammation, oxidative stress (OS), metabolic imbalance, mutagenesis, and teratogenesis. Oxidative responses are currently considered the first line molecular signal to potential toxic stimuli exposure, as the oxidative balance in electron exchange and reactive oxygen species signaling provides efficient harmful stimuli processing. Abnormal signaling or dysregulated ROS metabolism-OS-could be an important source of cellular toxicity, the source of a vicious cycle of environmental and oxidative signaling-derived toxicity. As chemical environmental pollutants, plastic NPs/MPs can also be a cause of such toxicity. Thus, we aimed to correlate the possible toxic effects of plastic NPs/MPs in zebrafish models, by focusing on OS and developmental processes. We found that plastic NPs/MPs toxic effects could be observed during the entire developmental span of zebrafish in close correlation with OS-related changes. Excessive ROS production and decreased antioxidant enzymatic defense due to plastic NPs/MPs exposure and accumulation were frequently associated with acetylcholinesterase activity inhibition, suggesting important neurodevelopmental negative outcomes (cognitive abnormalities, neurodevelopmental retardation, behavioral impairments) and extraneuronal effects, such as impaired digestive physiology.

Histopathological and Behavioral Impairments in Zebrafish (Danio rerio) Chronically Exposed to a Cocktail of Fipronil and Pyriproxyfen.

BACKGROUND: Lately, the high incidence of pesticide usage has attracted everyone's interest due to the serious effects produced. Fipronil (FIP) is a phenylpyrazole compound that acts on the insect's GABA neurotransmitter by inhibiting its activity. Moreover, the literature reports highlight its implication in neurodevelopmental abnormalities and oxidative stress production in different organisms. Similarly, pyriproxyfen (PYR) is known to affect insect activity by mimicking the natural hormones involved in the maturation of the young insects. The aim of the present study was to investigate the impact of the mixture of these pesticides on the tissues and behavior of zebrafish. METHODS: To assess the influence of this cocktail on zebrafish, three groups of animals were randomly selected and exposed to 0, 0.05, and 0.1 mg L-1 FIP and PYR mixture for five days. The fish were evaluated daily by the T-maze tests for locomotor activity and the light-dark test and recordings lasted four min. The data were quantified using the EthoVision software. RESULTS: Our results indicated significant changes in locomotor activity parameters that showed increased levels following exposure to the mixture of FIP and PYR. On the other hand, the mixture also triggered anxiety in the zebrafish, which spent more time in the light area than in the dark area. In addition, mixture-induced histological changes were observed in the form of numerous hemosiderin deposits found in various zebrafish tissues. CONCLUSIONS: The current findings indicate that the mixture of FIP and PYR can have considerable consequences on adult zebrafish and may promote or cause functional neurological changes in addition to histological ones.

The Role of Microglial Exosomes and miR-124-3p in Neuroinflammation and Neuronal Repair after Traumatic Brain Injury.

(1) Background: In this study, we aimed to explore the regulatory mechanism of miR-124-3p microglial exosomes, as they were previously reported to modulate neuroinflammation and promote neuronal repair following traumatic brain injury (TBI). (2) Methods: Studies investigating the impact of microglial exosomal miRNAs, specifically miR-124-3p, on injured neurons and brain microvascular endothelial cells (BMVECs) in the context of TBI were reviewed. (3) Results: Animal models of TBI, in vitro cell culture experiments, RNA sequencing analysis, and functional assays were employed to elucidate the mechanisms underlying the effects of miR-124-3p-loaded exosomes on neuroinflammation and neuronal repair. Anti-inflammatory M2 polarization of microglia, mTOR signaling suppression, and BMVECs-mediated autophagy were reported as the main processes contributing to neuroprotection, reduced blood-brain barrier leakage, and improved neurologic outcomes in animal models of TBI. (4) Conclusions: Microglial exosomes, particularly those carrying miR-124-3p, have emerged as promising candidates for therapeutic interventions in TBI. These exosomes exhibit neuroprotective effects, attenuate neuroinflammation, and promote neuronal repair and plasticity. However, further research is required to fully elucidate the underlying mechanisms and optimize their delivery strategies for effective treatment in human TBI cases.

Exploitation of Quercetin's Antioxidative Properties in Potential Alternative Therapeutic Options for Neurodegenerative Diseases.

Oxidative stress (OS) is a condition in which there is an excess of reactive oxygen species (ROS) in the body, which can lead to cell and tissue damage. This occurs when there is an overproduction of ROS or when the body's antioxidant defense systems are overwhelmed. Quercetin (Que) is part of a group of compounds called flavonoids. It is found in high concentrations in vegetables, fruits, and other foods. Over the past decade, a growing number of studies have highlighted the therapeutic potential of flavonoids to modulate neuronal function and prevent age-related neurodegeneration. Therefore, Que has been shown to have antioxidant, anticancer, and anti-inflammatory properties, both in vitro and in vivo. Due to its antioxidant character, Que alleviates oxidative stress, thus improving cognitive function, reducing the risk of neurodegenerative diseases. On the other hand, Que can also help support the body's natural antioxidant defense systems, thus being a potentially practical supplement for managing OS. This review focuses on experimental studies supporting the neuroprotective effects of Que in Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and epilepsy.

Effects of Single and Combined Ciprofloxacin and Lead Treatments on Zebrafish Behavior, Oxidative Stress, and Elements Content.

Even though the toxic effects of antibiotics and heavy metals have been extensively studied in the last decades, their combined adverse impact on aquatic organisms is poorly understood. Therefore, the objective of this study was to assess the acute effects of a ciprofloxacin (Cipro) and lead (Pb) mixture on the 3D swimming behavior, acetylcholinesterase (AChE) activity, lipid peroxidation level (MDA-malondialdehyde), activity of some oxidative stress markers (SOD-superoxide dismutase and GPx-glutathione peroxidase), and the essential elements content (Cu-copper, Zn-zinc, Fe-iron, Ca-calcium, Mg-magnesium, Na-sodium and K-potassium) in the body of zebrafish (Danio rerio). For this purpose, zebrafish were exposed to environmentally relevant concentrations of Cipro, Pb, and a mixture for 96 h. The results revealed that acute exposure to Pb alone and in mixture with Cipro impaired zebrafish exploratory behavior by decreasing swimming activity and elevating freezing duration. Moreover, significant deficiencies of Ca, K, Mg, and Na contents, as well as an excess of Zn level, were observed in fish tissues after exposure to the binary mixture. Likewise, the combined treatment with Pb and Cipro inhibited the activity of AChE and increased the GPx activity and MDA level. The mixture produced more damage in all studied endpoints, while Cipro had no significant effect. The findings highlight that the simultaneous presence of antibiotics and heavy metals in the environment can pose a threat to the health of living organisms.

Zebrafish as a Potential Model for Neurodegenerative Diseases: A Focus on Toxic Metals Implications.

In the last century, industrial activities increased and caused multiple health problems for humans and animals. At this moment, heavy metals are considered the most harmful substances for their effects on organisms and humans. The impact of these toxic metals, which have no biological role, poses a considerable threat and is associated with several health problems. Heavy metals can interfere with metabolic processes and can sometimes act as pseudo-elements. The zebrafish is an animal model progressively used to expose the toxic effects of diverse compounds and to find treatments for different devastating diseases that human beings are currently facing. This review aims to analyse and discuss the value of zebrafish as animal models used in neurological conditions, such as Alzheimer's disease (AD), and Parkinson's disease (PD), particularly in terms of the benefits of animal models and the limitations that exist.

Assessing the Neurotoxicity of a Sub-Optimal Dose of Rotenone in Zebrafish (Danio rerio) and the Possible Neuroactive Potential of Valproic Acid, Combination of Levodopa and Carbidopa, and Lactic Acid Bacteria Strains.

Parkinson's disease (PD) is an enigmatic neurodegenerative disorder that is currently the subject of extensive research approaches aiming at deepening the understanding of its etiopathophysiology. Recent data suggest that distinct compounds used either as anticonvulsants or agents usually used as dopaminergic agonists or supplements consisting of live active lactic acid bacteria strains might alleviate and improve PD-related phenotypes. This is why we aimed to elucidate how the administration of rotenone (ROT) disrupts homeostasis and the possible neuroactive potential of valproic acid (VPA), antiparkinsonian agents (levodopa and carbidopa - LEV+CARB), and a mixture of six Lactobacillus and three Bifidobacterium species (PROBIO) might re-establish the optimal internal parameters. ROT causes significant changes in the central nervous system (CNS), notably reduced neurogenesis and angiogenesis, by triggering apoptosis, reflected by the increased expression of PARKIN and PINK1 gene(s), low brain dopamine (DA) levels, and as opposed to LRRK2 and SNCA compared with healthy zebrafish. VPA, LEV/CARB, and PROBIO sustain neurogenesis and angiogenesis, manifesting a neuroprotective role in diminishing the effect of ROT in zebrafish. Interestingly, none of the tested compounds influenced oxidative stress (OS), as reflected by the level of malondialdehyde (MDA) level and superoxide dismutase (SOD) enzymatic activity revealed in non-ROT-exposed zebrafish. Overall, the selected concentrations were enough to trigger particular behavioral patterns as reflected by our parameters of interest (swimming distance (mm), velocity (mm/s), and freezing episodes (s)), but sequential testing is mandatory to decipher whether they exert an inhibitory role following ROT exposure. In this way, we further offer data into how ROT may trigger a PD-related phenotype and the possible beneficial role of VPA, LEV+CARB, and PROBIO in re-establishing homeostasis in Danio rerio.

Assessing Anti-Social and Aggressive Behavior in a Zebrafish (Danio rerio) Model of Parkinson's Disease Chronically Exposed to Rotenone.

Background: Rotenone (ROT) is currently being used in various research fields, especially neuroscience. Separated from other neurotoxins, ROT induces a Parkinson's disease (PD)-related phenotype that mimics the associated clinical spectrum by directly entering the central nervous system (CNS). It easily crosses through the blood−brain barrier (BBB) and accumulates in mitochondria. Unfortunately, most of the existing data focus on locomotion. This is why the present study aimed to bring novel evidence on how ROT alone or in combination with different potential ant(agonists) might influence the social and aggressive behavior using the counterclockwise rotation as a neurological pointer. Material and Methods: Thus, we exposed zebrafish to ROT­2.5 µg/L, valproic acid (VPA)­0.5 mg/mL, anti-parkinsonian drugs (LEV/CARB)­250 mg + 25 mg, and probiotics (PROBIO)­3 g for 32 days by assessing the anti-social profile and mirror tests and counterclockwise rotation every 4 days to avoid chronic stress. Results: We observed an abnormal pattern in the counterclockwise rotation only in the (a) CONTROL, (c) LEV/CARB, and (d) PROBIO groups, from both the top and side views, this indicating a reaction to medication and supplements administered or a normal intrinsic feature due to high levels of stress/anxiety (p < 0.05). Four out of eight studied groups­(b) VPA, (c) LEV/CARB, (e) ROT, and (f) ROT + VPA­displayed an impaired, often antithetical behavior demonstrated by long periods of time on distinct days spent on the right and the central arm (p < 0.05, 0.005, and 0.0005). Interestingly, groups (d) PROBIO, (g) ROT + LEV/CARB, and (h) ROT + PROBIO registered fluctuations but not significant ones in contrast with the above groups (p > 0.05). Except for groups (a) CONTROL and (d) PROBIO, where a normalized trend in terms of behavior was noted, the rest of the experimental groups exhibited exacerbated levels of aggression (p < 0.05, 0.005, and 0.001) not only near the mirror but as an overall reaction (p < 0.05, 0.005, and 0.001). Conclusions: The (d) PROBIO group showed a significant improvement compared with (b) VPA, (c) LEV/CARB, and ROT-treated zebrafish (e−h). Independently of the aggressive-like reactions and fluctuations among the testing day(s) and groups, ROT disrupted the social behavior, while VPA promoted a specific typology in contrast with LEV/CARB.

Comprehensive Review Regarding Mercury Poisoning and Its Complex Involvement in Alzheimer's Disease.

Mercury (Hg) is considered one of the most widespread toxic environmental pollutants, which seems to have multiple effects on organisms even at low concentrations. It has a critical role in many health problems with harmful consequences, with Hg primarily targeting the brain and its components, such as the central nervous system (CNS). Hg exposure was associated with numerous CNS disorders that frequently trigger Alzheimer's disease (AD). Patients with AD have higher concentrations of Hg in blood and brain tissue. This paper aims to emphasize a correlation between Hg and AD based on the known literature in the occupational field. The outcome shows that all these concerning elements could get attributed to Hg. However, recent studies did not investigate the molecular level of Hg exposure in AD. The present review highlights the interactions between Hg and AD in neuronal degenerations, apoptosis, autophagy, oxidative stress (OS), mitochondrial malfunctions, gastrointestinal (GI) microflora, infertility and altering gene expression.

Vitamin C Mitigates Oxidative Stress and Behavioral Impairments Induced by Deltamethrin and Lead Toxicity in Zebrafish.

Environmental contamination from toxic metals and pesticides is an issue of great concern due to their harmful effects to human health and the ecosystems. In this framework, we assessed the adverse effects when aquatic organisms are exposed to toxicants such as deltamethrin (DM) and lead (Pb), alone or in combination, using zebrafish as a model. Moreover, we likewise evaluated the possible protective effect of vitamin C (VC) supplementation against the combined acute toxic effects of the two toxicants. Juvenile zebrafish were exposed to DM (2 µg L-1) and Pb (60 µg L-1) alone and in combination with VC (100 µg L-1) and responses were assessed by quantifying acetylcholinesterase (AChE) activity, lipid peroxidation (MDA), some antioxidant enzyme activities (SOD and GPx), three-dimension locomotion responses and changes of elements concentrations in the zebrafish body. Our results show that VC has mitigative effects against behavioral and biochemical alterations induced by a mixture of contaminants, demonstrating that it can be used as an effective antioxidant. Moreover, the observations in the study demonstrate zebrafish as a promising in vivo model for assessing the neuroprotective actions of bioactive compounds.

The Possible Role of Bifidobacterium longum BB536 and Lactobacillus rhamnosus HN001 on Locomotor Activity and Oxidative Stress in a Rotenone-Induced Zebrafish Model of Parkinson's Disease.

BACKGROUND: As every organ within the body, the brain is also extremely susceptible to a plethora of noxious agents that change its chemistry. One component frequently found in current products against harmful species to crops is rotenone whose effect under prolonged exposure has been demonstrated to cause neurodegenerative disorders such as Parkinson's disease. The latest reports have indeed revealed that rotenone promotes Parkinson's in humans, but studies aiming to show congruent effects in zebrafish (Danio rerio) are lacking. Material and Methods. In this context, the aim of the present study was to demonstrate how chronic administration of rotenone for 3 weeks impairs the locomotor activity and sociability and induces oxidative stress in zebrafish. RESULTS: There were no statistically significant differences following the analysis of their social interaction and locomotor tests (p > 0.05). However, several exceptions have been noted in the control, rotenone, and probiotics groups when we compared their locomotor activity during the pretreatment and treatment interval (p < 0.05). We further assessed the role of rotenone in disturbing the detoxifying system as represented by three enzymes known as superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA). Despite the fact that there were no statistically significant changes within SOD and GPx levels between the control group and rotenone, probiotics, and rotenone + probiotics (p > 0.05), relevant changes have been observed between the analyzed groups (p < 0.05 and p < 0.005, respectively). On the other hand, significant differences (p < 0.05) have been observed for MDA when we analyzed the data between the control group and the other three groups. CONCLUSIONS: Our results suggest that rotenone can be successfully used to trigger Parkinson's disease-related symptomatology in zebrafish.

Zebrafish as a Screening Model to Study the Single and Joint Effects of Antibiotics.

The overuse of antibiotics combined with the limitation of wastewater facilities has resulted in drug residue accumulation in the natural environment. Thus, in recent years, the presence of antibiotic residues in the environment has raised concerns over the potential harmful effects on ecosystems and human health. The in vivo studies represent an essential step to study the potential impact induced by pharmaceutical exposure. Due to the limitations of traditional vertebrate model systems, zebrafish (Danio rerio) has recently emerged as a promising animal model to study the toxic effects of drugs and their therapeutic efficacy. The present review summarizes the recent advances made on the toxicity of seven representative classes of antibiotics, namely aminoglycosides, ß-lactams, macrolides, quinolones, sulfonamides, tetracyclines and polyether antibiotics, in zebrafish, as well as the combined effects of antibiotic mixtures, to date. Despite a significant amount of the literature describing the impact of single antibiotic exposure, little information exists on the effects of antibiotic mixtures using zebrafish as an animal model. Most of the research papers on this topic have focused on antibiotic toxicity in zebrafish across different developmental stages rather than on their efficacy assessment.

Response of aquatic macroinvertebrates communities to multiple anthropogenic stressors in a lowland tributary river.

In the current study the response of aquatic macroinvertebrate communities to multiple anthropogenic stressors in a typical lowland river that crosses pristine sectors situated toward headwaters, as well as densely populated urban areas was assessed. We wished to develop an effective bioassay procedure for assessing water and sediment quality in lotic ecosystems from Romania with the aid of macroinvertebrate organisms correlated with physico-chemical parameters and pollutants in both dissolved fractions and material bonded to sediment. A fast scanning approach of the river, from springs to the mouth, was employed. We found significant changes in physico-chemical parameters along a longitudinal gradient, the highest values being registered within the urban area and heavily agriculturally developed areas. The macroinvertebrates showed affinities for certain abiotic factors, emphasising their potential use for future studies as reliable ecological indicators, shaped by a synergic combination of urban effects and magnitude of type of land use.

Preliminary Results Regarding Sleep in a Zebrafish Model of Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is one of the most salient developmental neurological diseases and remarkable similarities have been found between humans and model animals of ASD. A common method of inducing ASD in zebrafish is by administrating valproic acid (VPA), which is an antiepileptic drug that is strongly linked with developmental defects in children. In the present study we replicated and extended the findings of VPA on social behavior in zebrafish by adding several sleep observations. Juvenile zebrafish manifested hyperactivity and an increase in ASD-like social behaviors but, interestingly, only exhibited minimal alterations in sleep. Our study confirmed that VPA can generate specific ASD symptoms, indicating that the zebrafish is an alternative model in this field of research.

Preliminary investigation of lower Danube pollution caused by potentially toxic metals.

The current study aims to assess the pollution status of the European river-sea system lower Danube River-Danube Delta-North West Black Sea, through an integrated analysis of metal concentrations in water, sediments and fish community. The Danube flows through numerous industrial cities and receives a significant amount of pollutants due to the reception of urban and industrial emissaries, as well as agricultural land runoff. Samples of water, sediments and fish (10 species) were collected from 7 representative sites along Danube River, Danube Delta and Black Sea shore. For the analysed fish species, potentially toxic and essential elements (Pb, Cd, As, Cu, Fe, Zn, Mg, Ca, Na, K) from muscle and liver samples were measured and discussed. Measurement of elements and other environmental quality parameters were determined for water and sediments. The Black Sea area, represented by S6 and S7, received sediments from Danube with the lowest concentrations of Cd (0.05 ± 0.01 µg g-1, respectively 0.01 ± 0.001 µg g-1), Pb (3 ± 0.03 µg g-1, respectively 2 ± 0.03 µg g-1), As (2 ± 0.02 µg g-1, respectively 1.4 ± 0.3 µg g-1), Ni (8.9 ± 0.1 µg g-1, respectively 5.2 ± 0.2 µg g-1), Cr (8 ± 0.7 µg g-1, respectively 5 ± 0.2 µg g-1), Cu (3 ± 0.1 µg g-1, respectively 2 ± 0.04 µg g-1), Fe(6 ± 0.3 µg g-1, respectively 3 ± 0.1 µg g-1) and Zn (0.03 ± 0.003 µg g-1, respectively 0.017 ± 0.001 µg g-1). These results suggest that the Danube Delta system plays an important role in filtering the pollutants. Based on the biota and water analysis, there was no correlation observed between Cd, respectively Pb concentration in the environment and fish body (Person Coef. = -0.02 in muscle tissue and -0.01 in liver tissue, respectively Pearson Coeff. = -0.06 in muscle tissue and 0.1 in liver tissue). Cadmium remained an active element in the pollution of the Danube area (S1 and S2), with high concentration in the water matrix (0.14 ± 0.02 µg L-1, respectively 0.05 ± 0.01 µg L-1) and fish muscle (0.15 ± 0.03 µg g-1f.w. in C. carpio - S2). This fact was confirmed by several other studies.

Vitamin C Attenuates Oxidative Stress and Behavioral Abnormalities Triggered by Fipronil and Pyriproxyfen Insecticide Chronic Exposure on Zebrafish Juvenile.

Chronic exposure to synthetic insecticides in the early life of a child can lead to a series of disorders. Several causes as parental age, maternal smoking, birth complications, and exposure to toxins such as insecticides on childhood can lead to Autism spectrum disorder (ASD) occurrence. The aim of this study was to evaluate the potential protective role of vitamin C (Vit. C) from children's supplements after 14 days chronic exposure to insecticide mixture fipronil (Fip) + pyriproxyfen (Pyr) on juvenile zebrafish for swimming performances, social behavior and oxidative stress associated with ASD model. Juvenile (14-17 mm) wild-type AB zebrafish (Danio rerio) (45 days) were exposed to relevant concentrations: vit. C (25 µg L-1), Fip (600 µg L-1/1.372 µM) + Pyr (600 µg L-1/1.89 µM), and [Fip (600 µg L-1/1.372 µM) + Pyr (600 µg L-1 /1.89 µM)] + vit. C (25 µg L-1). Our results showed that insecticides can disturb the social behavior of zebrafish during 14 days of the administration, decreased the swimming performances, and elevated the oxidative stress biomarkers of SOD (superoxide dismutase), GPx (glutathione peroxidase), and MDA (malondialdehyde). The vitamin C supplement significantly attenuated the neurotoxicity of insecticide mixture and oxidative stress. This study provides possible in vivo evidence to show that vitamin C supplements could attenuate oxidative stress and brain damage of fipronil and pyriproxyfen insecticide chronic exposure on zebrafish juvenile.

Parkinson's Disease-Induced Zebrafish Models: Focussing on Oxidative Stress Implications and Sleep Processes.

The complex yet not fully understood pathophysiology of Parkinson's disease includes an important molecular component consisting of oxidative status changes, thus leading to oxidative stress occurrence. While no particular evidence has been reported that describes the relationship between oxidative stress and the molecular mechanisms behind Parkinson's disease development, animal model studies has shown that oxidative stress induction could modulate Parkinson's disease symptomatology. Despite the inability to perfectly replicate human disease in animals and despite that Parkinson's disease has not been reported in any animal species, animal modeling is one of the most important tools in understanding the complex mechanisms of human disorders. In this way, this study is aimed at detailing this particular relationship and describing the molecular mechanisms underlying Parkinson's disease in animal models, focusing on the potential advantages and disadvantages of zebrafish in this context. The information relevant to this topic was gathered using major scientific database research (PubMed, Google Scholar, Web of Science, and Scopus) based on related keywords and inclusion criteria. Thus, it was observed that oxidative stress possesses an important role in Parkinson's disease as shown by numerous animal model studies, many of which are based on rodent experimental models. However, an emerging impact of the zebrafish model was observed in the research of Parkinson's disease pathological mechanisms with regard to disease development factors and the cause-effect relationship between oxidative stress and comorbidities (such as depression, hyposmia, fatigue, sleep disturbances, and cognitive deficits) and also with regard to the pharmacological potential of antioxidant molecules in Parkinson's disease treatment.