The fate and oxidative stress of different sized SiO2 nanoparticles in zebrafish (Danio rerio) larvae

Grape seed extract protects rat offspring hippocampus from the silicon dioxide nanoparticles' neurotoxicity

Silicon dioxide nanoparticles (SiO2-NPs) can be found in many products, such as composites, paints, ceramics, consumer products, and food additives. We recently demonstrated that via breastfeeding, SiO2-NPs transfer to the offspring's brain, interfering negatively with hippocampus development. In this work, we evaluated the protective effect of grape seed extract (GSE) against the adverse effects of SiO2-NPs. After delivery, animals were administered 25 mg/kg SiO2-NPs with/without GSE (300 mg/kg) for 20 days (from 2nd to 21st days post-delivery) by gavage. SiO2-NPs increased malondialdehyde concentration and decreased antioxidant activity in the offspring's hippocampi. The mean number of dark neurons (DNs) was significantly higher in the hippocampi of the SiO2-NPs group, whereas the mean number of DCX + cells was significantly lower than in the control group. The offspring in the SiO2-NPs groups had a weak cognitive performance in adulthood. Interestingly, these adverse effects of SiO2-NPs were alleviated in the GSE-treated groups. Therefore, GSE can attenuate the damaging effects of maternal exposure to SiO2-NPs during lactation.

The size-dependent in vivo toxicity of amorphous silica nanoparticles: A systematic review

The extensive application of amorphous silica nanoparticles (aSiNPs) in recent years has resulted in unavoidable human exposure in daily life, thus raising widespread concerns regarding the safety of aSiNPs on human health. The particle size is one of the important characteristics of nanomaterials that could influence their toxicity. For the reason that particles with smaller sizes possess larger surface area, which may lead to higher surface activity and biological reactivity. However, due to the complexity of experimental conditions and biological systems, the relationship between the particle size and the toxic effect of aSiNPs remains unclear. Therefore, this systematic review aims to investigate how particle size influences the toxic effect of aSiNPs in vivo and to analyze the relevant experimental factors affecting the size-dependent toxicity of aSiNPs in vivo. We found that 83.8% of 35 papers included in the present review came to the conclusion that smaller-sized aSiNPs exhibited stronger toxicity, though a few papers (6 papers) put forward different opinions. The reasons for smaller aSiNPs manifested greater toxicity were summarized. In addition, certain important experimental factors could influence the size-dependent effects and in vivo toxicity of aSiNPs, such as the synthesis method of aSiNPs, disperse medium of aSiNPs, administration route of aSiNPs, species or strain of experimental animals, sex of experimental animals, aggregation/agglomeration and protein corona of aSiNPs.

Long-term exposure to small-sized silica nanoparticles (SiO2-NPs) induces oxidative stress and impairs reproductive performance in adult zebrafish (Danio rerio)

The widespread use of silica nanoparticles (SiO2-NPs) in various industries, including chemical polishing, cosmetics, varnishes, medical, and food products, has increased the risk of their release into aquatic ecosystems. The toxic effects of small-size SiO2-NPs on the reproductive performance of zebrafish (Danio rerio) have yet to be widely studied. This study aimed to investigate the impact of chronic exposure to small-sized (35 ± 6 nm) SiO2-NPs on adult zebrafish through waterborne exposure to concentrations of 5 (SNP5), 10 (SNP10), 15 (SNP15), and 20 (SNP20) μg/L of SiO2-NPs for 28 days. Our results showed that SiO2-NPs significantly impacted several biochemical parameters, including cholesterol, triglycerides, LDL, HDL, total protein, albumin, urea levels, and alkaline phosphatase and aspartate aminotransferase activity. Cortisol and glucose levels in the SNP20 group significantly differed from the control group. All the exposed groups, apart from SNP5, experienced a significant increase in their total immunoglobulin levels and lysozyme activity. While there was a considerable increase in the activity of catalase and superoxide dismutase in all exposed groups, the expression of antioxidant genes did not appear to be affected. Furthermore, the expression level of il8 was significantly higher in SNP5 and SNP10 than in other treatments. Exposure to SiO2-NPs caused a decrease in gonad weight, absolute fecundity, and larval survival rate, particularly in the SNP20 group. The present study indicates that SiO2-NPs can harm zebrafish and thus further research is necessary to assess their health and environmental risks.

Nanosilica and copper ecotoxicity in Gambusia holbrooki fish

When silica nanoparticles (SiNP) reach the water bodies interact with the already existing pollutants in the environments. This study aimed to evaluate the ecotoxicity of SiNP under the presence/absence of Cu in mosquitofish (Gambusia holbrooki). Fish were exposed to 0, 10 and 100 mg SiNP L-1, alone or mixed with Cu (0.25 mg L-1). After 96 h, the amount of colony forming units (CFU) of bacteria living on the skin mucus was analysed, and oxidative stress, tissue damage enzymes, and neurotoxicity were evaluated. We observed a reduction in CFU when Cu was present in the media. The liver was the target organ, evidencing a decrease in tissue damage enzymatic activities, activation of the antioxidant system in all treatments, and lipid oxidative damage when the SiNP and Cu were mixed. Overall, SiNP ecotoxicity was proved, which could also be enhanced by the presence of ubiquitous elements such as metals.

A Short Review of the Toxicity of Dentifrices-Zebrafish Model as a Useful Tool in Ecotoxicological Studies

This review aims to summarize the literature data regarding the effects of different toothpaste compounds in the zebrafish model. Danio rerio provides an insight into the mechanisms of the ecotoxicity of chemicals as well as an assessment of their fate in the environment to determine long-term environmental impact. The regular use of adequate toothpaste with safe active ingredients possessing anti-bacterial, anti-inflammatory, anti-oxidant, and regenerative properties is one of the most effective strategies for oral healthcare. In addition to water, a typical toothpaste consists of a variety of components, among which three are of predominant importance, i.e., abrasive substances, fluoride, and detergents. These ingredients provide healthy teeth, but their environmental impact on living organisms are often not well-known. Each of them can influence a higher level of organization: subcellular, cellular, tissue, organ, individual, and population. Therefore, it is very important that the properties of a chemical are detected before it is released into the environment to minimize damage. An important part of a chemical risk assessment is the estimation of the ecotoxicity of a compound. The zebrafish model has unique advantages in environmental ecotoxicity research and has been used to study vertebrate developmental biology. Among others, the advantages of this model include its external, visually accessible development, which allows for providing many experimental manipulations. The zebrafish has a significant genetic similarity with other vertebrates. Nevertheless, translating findings from zebrafish studies to human risk assessment requires careful consideration of these differences.

ABC transporter-mediated MXR mechanism in fish embryos and its potential role in the efflux of nanoparticles

ATP-binding cassette (ABC) transporters are believed to protect aquatic organisms by pumping xenobiotics out, and recent investigation has suggested their involvement in the detoxification and efflux of nanoparticles (NPs), but their roles in fish embryos are poorly understood. In this regard, this paper summarizes the recent advances in research pertaining to the development of ABC transporter-mediated multi-xenobiotic resistance (MXR) mechanism in fish embryos and the potential interaction between ABC transporters and NPs. The paper focuses on: (1) Expression, function, and modulation mechanism of ABC proteins in fish embryos; (2) Potential interaction between ABC transporters and NPs in cell models and fish embryos. ABC transporters could be maternally transferred to fish embryos and thus play an important role in the detoxification of various chemical pollutants and NPs. There is a need to understand the specific mechanism to benefit the protection of aquatic resources.

Nanosilica size-dependent toxicity in Ceriodaphnia reticulata (Cladocera)

Silica nanoparticles (SiNP) are the most produced nanomaterials due to their variety of applications. When released to environments, surface water bodies are their main final sink. SiNP toxicity is still inconclusive and may vary according to particle properties such as their size. We analyzed the size-related effects of SiNP (22 and 244 nm) on mortality, life history traits, and oxidative stress in the cladoceran Ceriodaphnia reticulata. The smaller SiNP (LC5072 h: 105.5 µg/ml) were more lethal than the larger ones (LC5072 h >500 µg/ml). The 22 nm-sized SiNP decreased the number of molts and neonates, increased superoxide dismutase and inhibited glutathione S-transferase activities, while larger SiNP did not exert substantial effects on the organisms at the tested concentrations. In conclusion, SiNP toxicity depended on their size, and this information should be considered for regulatory purposes and to the development of safe-by-design nanoproducts to ultimately guarantee the environment protection.

Binary toxicity of engineered silica nanoparticles (nSiO2) and arsenic (III) to zebrafish (Danio rerio): application of response surface methodology

Increasing production and use of engineered nanoparticles (NPs) leads to their release into the aquatic environments where they can interact with other hazardous contaminants, such as heavy metals, and threaten aquatic organisms. This study considers the ecotoxicity of arsenic (III) and silica nanoparticles (nSiO₂), individually and simultaneously, to the zebrafish (Danio rerio) using response surface methodology (RSM) under central composite design (CCD). The results revealed that in the treatments within the concentration range of 1 to 5 mg L^-1 arsenic and 1-100 mg L^-1 nSiO₂, no mortality was observed after 96 h. The optimal conditions for achieving the lowest effect of simultaneous toxicity in the concentration range of nSiO₂ and arsenic were 100 and 7 mg L^-1, respectively. Accordingly, the desirable function of the predicted model was found to be 0.78. According to these results, arsenic is toxic for zebrafish. Importantly, exposure to nSiO₂ alone did not cause acute toxicity in the studied species, while arsenic toxicity decreased by increasing the concentration of nSiO₂.

Characterization of oxidative damage induced by nanoparticles via mechanism-driven machine learning approaches

The wide application of TiO₂-based engineered nanoparticles (nTiO₂) inevitably led to release into aquatic ecosystems. Importantly, increasing studies have emphasized the high risks of nTiO₂ to coastal environments. Bivalves, the representative benthic filter feeders in coastal zones, acted as important roles to assess and monitor the toxic effects of nanoparticles. Oxidative damage was one of the main toxic mechanisms of nTiO₂ on bivalves, but the experimental variables/nanomaterial characteristics were diverse and the toxicity mechanism was complex. Therefore, it was very necessary to develop machine learning model to characterize and predict the potential toxicity. In this study, thirty-six machine learning models were built by nanodescriptors combined with six machine learning algorithms. Among them, random forest (RF) - catalase (CAT), k-neighbors classifier (KNN) - glutathione peroxidase (GPx), neural networks - multilayer perceptron (ANN) - glutathione s-transferase (GST), random forest (RF) - malondialdehyde (MDA), random forest (RF) - reactive oxygen species (ROS), and extreme gradient boosting decision tree (XGB) - superoxide dismutase (SOD) models performed good with high accuracy and balanced accuracy for both training sets and external validation sets. Furthermore, the best model revealed the predominant factors (exposure concentration, exposure periods, and exposure matrix) influencing the oxidative stress induced by nTiO₂. These results showed that high exposure concentrations and short exposure-intervals tended to cause oxidative damage to bivalves. In addition, gills and digestive glands could be vulnerable to nTiO₂-induced oxidative damage as tissues/organs differences were the important factors controlling MDA activity. This study provided insights into important nano-features responsible for the different indicators of oxidative stress and thereby extended the application of machine learning approaches in toxicological assessment for nanoparticles.

Has PdCu@GO effect on oxidant/antioxidant balance? Using zebrafish embryos and larvae as a model

Industrial products containing PdCu@GO can gain access to the aquaculture environment, causing dangerous effects on living biota. In this study, the developmental toxicity of zebrafish treated with different concentrations (50, 100, 250, 500 and 1000 μg/L) of PdCu@GO was investigated. The findings showed that PdCu@GO administration decreased the hatchability and survival rate, caused dose-dependent cardiac malformation. Reactive oxygen species (ROS) and apoptosis were also inhibited in a dose-dependent manner, with acetylcholinesterase (AChE) activity affected by nano-Pd exposure. As evidence for oxidative stress, malondialdehyde (MDA) level increased and superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (GPx) activities and glutathione (GSH) level decreased due to the increase in PdCu@GO concentration. Our research, it was determined that the oxidative stress stimulated by the increase in the concentration of PdCu@GO in zebrafish caused apoptosis (Caspase-3) and DNA damage (8-OHdG). Stimulation of ROS, inflammatory cytokines, tumor Necrosis Factor Alfa (TNF-α) and interleukin - 6 (IL-6), which act as signaling molecules to trigger proinflammatory cytokine production, induced zebrafish immunotoxicity. However, it was determined that the increase of ROS induced teratogenicity through the induction of nuclear factor erythroid 2 level (Nrf-2), NF-κB and apoptotic signaling pathways triggered by oxidative stress. Taken together with the research findings, the study contributed to a comprehensive assessment of the toxicological profile of PdCu@GO by investigating the effects on zebrafish embryonic development and potential molecular mechanisms.

Zn-Al layered double hydroxides induce embryo malformations and impair locomotion behavior in Danio rerio

Layered double hydroxides (LDHs) are stimuli-responsive anionic nanoclays. The vast possibilities of using LDHs can lead to their existence in the ecosystem, raising a question of potential ecological concern. However, little is known about the effect of these nanomaterials on freshwater organisms. The present study aimed to assess the ecotoxicological effects of Zinc-Aluminium LDH-nitrate (ZnAl LDH-NO₃) in zebrafish (Danio rerio) early life stages. The endpoints measured were mortality, malformations and hatching rate after exposure of D. rerio embryos and larvae to ZnAl LDH-NO₃ following the OECD 236 guideline. The behavioral, biochemical (markers of oxidative stress and neurotoxicity), and molecular (at DNA level) alterations were also assessed using sub-lethal concentrations. No observable acute effects were detected up to 415.2 mg LDH/L while the 96 h-LC₅₀ was estimated as 559.9 mg/L. Tested LDH caused malformations in D. rerio embryos, such as pericardial edema, incomplete yolk sac absorption and tail deformities (96 h-EC₅₀ = 172.4 mg/L). During the dark periods, the locomotor behavior in zebrafish larvae was affected upon ZnAl LDH-NO₃ exposure. However, no significant biochemical and molecular changes were recorded. The present findings suggest that ZnAl LDH-NO₃ can be regarded as a non-toxic nanomaterial towards D. rerio (E/LC₅₀ > > 100 mg/L) although impairment of the locomotion behavior on zebrafish embryos can be expected at concentrations below 100 mg/L.

Effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on reproductive and endocrine function in female zebrafish (Danio rerio)

BACKGROUND

Polybrominated diphenyl ethers (PBDEs), a group of brominated flame retardants (BFRs), were reported exist extensively in various ecological environmental. Studies have indicated that PBDEs induce reproductive toxic effects on human health, but the mechanisms remain poorly understood. In this study, the adult female zebrafish were used to investigate the effects of 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) on the reproductive endocrine system and its mechanism.

METHODS

Female zebrafish (AB strains) were continuously exposed to BDE-47 at the concentrations of 0, 10, 50, 100 and 500 µg/L till 21 days. The morphology of ovary were stained and evaluated with hematoxylin-eosin (H&E), and levels of sex hormones including follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T) and 17β-estradiol (E₂) and the biomarkers of oxidative stress such as superoxide dismutase (SOD) and malondialdehyde (MDA), were measured via ELISA. Subsequently, the expression of genes along the hypothalamic pituitary-gonad (HPG) and oxidative stress were determined using quantitative real-time PCR (qRT-PCR).

RESULT

The results showed that exposure to high level of BDE-47 reduced the index of condition factor (CF) and gonadosomatic index (GSI). Treatment with BDE-47 impaired the normal development and structure of oocytes in zebrafish ovary. Moreover, the steroid hormone of FSH, LH, T and E₂ were significantly decreased in BDE-47 exposure group. A dose-dependent elevation in SOD activity and MDA levels were recorded. Meanwhile, the transcription level of cyp19a, cyp19b, fshβ, lhβ were up-regulated while the transcription of fshr, lhr, cyp17a, 17βhsd were down-regulated in the gonad of female adult zebrafish.

CONCLUSION

Exposure to BDE-47 have detrimental impact on the development of ovary, decreasing sex hormone levels, inducing oxidative damage as well as altering HPG axis-related genes.

On the In Vitro and In Vivo Hazard Assessment of a Novel Nanomaterial to Reduce the Use of Zinc Oxide in the Rubber Vulcanization Process

Zinc oxide (ZnO) is the most efficient curing activator employed in the industrial rubber production. However, ZnO and Zn(II) ions are largely recognized as an environmental hazard being toxic to aquatic organisms, especially considering Zn(II) release during tire lifecycle. In this context, aiming at reducing the amount of microcrystalline ZnO, a novel activator was recently synthetized, constituted by ZnO nanoparticles (NPs) anchored to silica NPs (ZnO-NP@SiO₂-NP). The objective of this work is to define the possible hazards deriving from the use of ZnO-NP@SiO₂-NP compared to ZnO and SiO₂ NPs traditionally used in the tire industry. The safety of the novel activators was assessed by in vitro testing, using human lung epithelial (A549) and immune (THP-1) cells, and by the in vivo model zebrafish (Danio rerio). The novel manufactured nanomaterial was characterized morphologically and structurally, and its effects evaluated in vitro by the measurement of the cell viability and the release of inflammatory mediators, while in vivo by the Fish Embryo Acute Toxicity (FET) test. Resulting data demonstrated that ZnO-NP@SiO₂-NP, despite presenting some subtoxic events, exhibits the lack of acute effects both in vitro and in vivo, supporting the safe-by-design development of this novel material for the rubber industry.

Neurotoxicity of tetrabromobisphenol A and SiO2 nanoparticle co-exposure in zebrafish and barrier function of the embryonic chorion

Silicon dioxide nanoparticles (n-SiO₂) absorb tetrabromobisphenol A (TBBPA) and modify its bioavailability and toxicity in the aquatic phase; embryonic chorion is an efficient barrier against nanoparticles (e.g., SiO₂) and influences their toxicity. However, few studies have investigated developmental neurotoxicity in fish after co-exposure to TBBPA and n-SiO₂, especially considering the barrier function of the chorion. In the present study, zebrafish embryos were exposed to TBBPA (50, 100, and 200 μg/L) alone or in combination with n-SiO₂ (25 mg/L) until 24 or 120 h post fertilization (hpf), in the presence and absence of the chorion. The results confirmed that TBBPA exposure alone significantly downregulated the expression of neurodevelopment marker genes (mbp, alpha-tubulin, shha, and gfap), altered acetylcholinesterase activity and acetylcholine content, and affected locomotor behavior at different developmental stages. Moreover, the results indicated that n-SiO₂ promoted TBBPA-induced neurotoxic effects in zebrafish larvae at 120 hpf, including further repression of the transcription of CNS-related genes, disruption of the cholinergic system, and decrease in the average swimming speed under dark/light stimulation. However, scanning electron microscopy/energy dispersive spectroscopy analysis revealed that at 24 hpf, the embryonic chorion efficiently blocked n-SiO₂ and consequently decreased the bioaccumulation of TBBPA and TBBPA-induced neurotoxicity in dechorionated zebrafish embryos. Taken together, the results demonstrate that n-SiO₂ affected the bioavailability and neurodevelopmental toxicity of TBBPA, and their combined toxicity to zebrafish embryos was mitigated by embryonic chorion, which will facilitate risk assessment on n-SiO₂ and TBBPA and improve understanding the function of the fish embryonic chorion.

The impact of single walled carbon nanotubes on the expression of microRNA in zebrafish (Danio rerio) embryos

Objective. Single-walled carbon nanotubes (SWCNTs) are able to cross the blood-brain barrier, penetrate through the cell membrane, and accumulate in the cell nucleus, which purposefully allows their use in the health sciences as imaging probes and drug carriers in the cancer therapy. The aim of this study was to investigate the effect of low doses of SWCNTs on the expression of microRNAs associated with the cell proliferation and the brain development in zebrafish (Danio rerio) embryos. Methods. The zebrafish embryos (72 h post fertilization) were exposed to low doses of SWCNTs (2 and 8 ng/ml of medium) for 24 or 72 h. The microRNAs (miR-19, miR-21, miR-96, miR-143, miR-145, miR-182, and miR-206) expression levels were measured by quantitative polymerase chain reaction analysis. Results. It was found that low doses of SWCNTs elicited dysregulation in the expression of numerous cell proliferation and brain development-related microRNAs (miR-19, miR-21, miR-96, miR-143, miR-145, miR-182, and miR-206) in dose- (2 and 8 ng/ml of medium) as well as malformations in the zebrafish embryos brain development in a time-dependent (24 and 72 h) manner. Conclusion. Taken together, the present data indicate that the low doses of SWCNTs disturbed the genome functions and reduced the miR-19, miR-21, miR-96, miR-143, miR-145, miR-182, and miR-206 expression levels in dose- and time-dependent manners and interrupted the brain development in the zebrafish embryos indicating for both the genotoxic and the neurotoxic interventions.

Hippocampal toxicity of metal base nanoparticles. Is there a relationship between nanoparticles and psychiatric disorders?

Metal base nanoparticles are widely produced all over the world and used in many fields and products such as medicine, electronics, cosmetics, paints, ceramics, toys, kitchen utensils and toothpastes. They are able to enter the body through digestive, respiratory, and alimentary systems. These nanoparticles can also cross the blood brain barrier, enter the brain and aggregate in the hippocampus. After entering the hippocampus, they induce oxidative stress, neuro-inflammation, mitochondrial dysfunction, and gene expression alteration in hippocampal cells, which finally lead to neuronal apoptosis. Metal base nanoparticles can also affect hippocampal neurogenesis and synaptic plasticity that both of them play crucial role in memory and learning. On the one hand, hippocampal cells are severely vulnerable due to their high metabolic activity, and on the other hand, metal base nanoparticles have high potential to damage hippocampus through variety of mechanisms and affect its functions. This review discusses, in detail, nanoparticles' detrimental effects on the hippocampus in cellular, molecular and functional levels to reveal that according to the present information, which types of nanoparticles have more potential to induce hippocampal toxicity and psychiatric disorders and which types should be more evaluated in the future studies.

Ecotoxicological evaluation of zebrafish liver (Danio rerio) induced by dibutyl phthalate

Dibutyl phthalate (DBP), one of the most commonly applied plasticizers, has been frequently detected in the aquatic environment, posing potential risks to aquatic organisms. Currently, reports about the toxicity of zebrafish liver with DBP exposure are rare, and the toxic mechanism is still not clear. In this study, zebrafish (Danio rerio) were used to explore the ecotoxicological effects of DBP from the physiological, biochemical, genetic, and molecular levels. The results showed oxidative stress, lipid peroxidation, and DNA damage occurred in zebrafish liver according to changes in antioxidant enzymes, MDA and 8-OHdG content. AchE activity was always active, and negatively correlated with the DBP concentration. The expression of Cu/Zn-sod and gpx genes were similar to that of antioxidant enzymes from 7 to 21 days, while in the end, the inconsistent result appeared due to the time lag effect in protein modification, gene transcription and translation. Besides, the mRNA abundance of Caspase-3 and p53 were upregulated, showing a "dose-response" relationship. The integrated biomarker reaction indicated that the effects of exposure time on zebrafish liver was 14th day> 28th day> 7th day> 21th day. These results are of great significance to evaluate the toxicological effects and explore the toxic mechanism of DBP on aquatic organisms.

Silica nanoparticles induce pyroptosis and cardiac hypertrophy via ROS/NLRP3/Caspase-1 pathway

Growing literatures suggest that silica nanoparticles (SiNPs) exposure is correlated with adverse cardiovascular effects. Cardiac hypertrophy is one of the most common risk factors for heart failure. However, whether SiNPs involved in cardiac hypertrophy and the underlying mechanisms was remained unexploited. Our study aimed to investigate the molecular mechanisms of SiNPs on pyroptosis and cardiac hypertrophy. The in vivo results found that SiNPs induced ultrastructural change and histopathological damage, accompanied by oxidative damage occurred and increased levels of inflammatory factors (IL-18 and IL-1β) in heart tissue. In addition, SiNPs could upregulate the expressions of cardiac hypertrophy-related special marker including ANP, BNP, β-MHC, it also elevated the pyroptosis-related protein, such as NLRP3, Cleaved-Caspase-1, GSDMD, IL-18 and Cleaved-IL-1β in vivo. For in vitro study, SiNPs increased the intracellular ROS generation and activated the NLRP3/Caspase-1/GSDMD signaling pathway in cardiomyocytes. Whereas, the NADPH oxidase (NOX) inhibitor VAS2870 had effectively inhibited the ROS level and suppressed the expression of NLRP3, ASC, Pro-Caspase-1, Cleaved-Caspase-1, N-GSDMD, IL-18, Cleaved-IL-1β, ANP, BNP and β-MHC. Moreover, transfected with si-NLRP3 or adopted with Caspase-1 inhibitor VX-765 in cardiomyocytes showed an inhibitory effect on SiNPs-induced pyroptosis and cardiac hypertrophy. In summary, our results demonstrated that SiNPs could trigger pyroptosis and cardiac hypertrophy via ROS/NLRP3/Caspase-1 signaling pathway.

Enhanced Antioxidant Effects of the Anti-Inflammatory Compound Probucol when Released from Mesoporous Silica Particles

Brain endothelial cells mediate the function and integrity of the blood brain barrier (BBB) by restricting its permeability and exposure to potential toxins. However, these cells are highly susceptible to cellular damage caused by oxidative stress and inflammation. Consequent disruption to the integrity of the BBB can lead to the pathogenesis of neurodegenerative diseases. Drug compounds with antioxidant and/or anti-inflammatory properties therefore have the potential to preserve the structure and function of the BBB. In this work, we demonstrate the enhanced antioxidative effects of the compound probucol when loaded within mesoporous silica particles (MSP) in vitro and in vivo zebrafish models. The dissolution kinetics were significantly enhanced when released from MSPs. An increased reduction in lipopolysaccharide (LPS)-induced reactive oxygen species (ROS), cyclooxygenase (COX) enzyme activity and prostaglandin E₂ production was measured in human brain endothelial cells treated with probucol-loaded MSPs. Furthermore, the LPS-induced permeability across an endothelial cell monolayer by paracellular and transcytotic mechanisms was also reduced at lower concentrations compared to the antioxidant ascorbic acid. Zebrafish pre-treated with probucol-loaded MSPs reduced hydrogen peroxide-induced ROS to control levels after 24-h incubation, at significantly lower concentrations than ascorbic acid. We provide compelling evidence that the encapsulation of antioxidant and anti-inflammatory compounds within MSPs can enhance their release, enhance their antioxidant effects properties, and open new avenues for the accelerated suppression of neuroinflammation.

Maternal exposure to silicon dioxide nanoparticles reduces hippocampal neurogenesis and synaptogenesis and induces neurodegeneration in rat offspring hippocampus

Silicon dioxide nanoparticles (SiO₂-NPs) are among the most widely used nanoparticles because of their chemical-physical properties. Since most brain maturation occurs in the neonatal period in humans and many mammals, it is important to understand how NPs may affect this process. This study tested the hypothesis that SiO2-NPs from treated dams could affect the hippocampus of neonatal rats during lactation. Twenty-four pregnant rats, after delivery, were divided into three groups of control, SiO₂-NPs (25 mg/kg) and SiO₂-NPs (100 mg/kg). The rats were treated from 2^nd to 21^st days post-delivery by gavage and the effects of these NPs were evaluated in the offspring's hippocampi to reveal the effects of maternal exposure to SiO₂-NPs during lactation on the offspring's hippocampi. The offspring in the SiO₂-NPs groups had higher malondialdehyde concentration and lower antioxidant activity in the hippocampi than the non-treated control group. The mean number of doublecortin positive (DCX⁺) cells and synaptophysin expression in the hippocampi of the SiO₂-NPs groups were significantly lower than the control group, whereas the mean number of dark neurons was significantly higher. Also, animals in the SiO₂-NPs groups had a weak cognitive performance in adulthood. In conclusion, maternal exposure to SiO₂-NPs via breastfeeding could affect offspring's hippocampal neurogenesis and synaptogenesis, leading to impaired cognitive performance.

Nanomaterials-induced toxicity on cardiac myocytes and tissues, and emerging toxicity assessment techniques

The extensive production and use of nanomaterials have resulted in the continuous release of nano-sized particles into the environment, and the health risks caused by exposure to these nanomaterials in the occupational population and the general population cannot be ignored. Studies have found that particle exposure is closely related to cardiovascular disease. In addition, there have been many reports that nanomaterials can enter the heart tissue, accumulate and then cause damage. Therefore, in the present article, literature related to nanomaterials-induced cardiotoxicity in recent years was collected from the PubMed database, and then organized and summarized to form a review. This article mainly discusses heart damage caused by nanomaterials from the following three aspects: Firstly, we summarize the research 8 carbon nanotubes, etc. Secondly, we discuss in depth the possible underlying mechanism of the damage to the heart caused by nanoparticles. Oxidative stress damage, mitochondrial damage, inflammation and apoptosis have been found to be key factors. Finally, we summarize the current research models used to evaluate the cardiotoxicity of nanomaterials, highlight reliable emerging technologies and in vitro models that have been used for toxicity evaluation of environmental pollutants in recent years, and indicate their application prospects.

Ecotoxicity of silica nanoparticles in aquatic organisms: An updated review

This review aims to (i) provide a current overview of the main characteristics of SiNP (physical and chemical properties, applications, and emissions), (ii) evaluate the scientific production up to date concerning SiNP, with focus on their toxic effects, through a bibliometric analysis, (iii) describe the main toxic mechanisms of SiNP, (iv) assess the current knowledge about ecotoxicity of SiNP on aquatic organisms (marine and freshwater), and (v) identify the main gaps in the knowledge of SiNP toxicity from an environmentally point of view. The scientific production of SiNP concerning their chemical and physical characteristics has increased exponentially. However, little information is available regarding their ecotoxicity. Particle functionalization is a key factor that reduces SiNP toxicity. Most of the studies employed standard species as test organisms, being the local/native ones poorly represented. Further studies employing long-term exposures and environmentally relevant concentrations are needed to deepen the knowledge about this emergent pollutant.

Characterization and preliminary safety evaluation of nano-SiO2 isolated from instant coffee

The physiological and toxicological evaluation of nano-silicon dioxide (nano-SiO2) particles in food is important for ensuring food safety. In this study, nano-SiO2 particles isolated from five brands of instant coffee, were structurally characterized using transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, dynamic light scattering, and zeta potential analyses. Their toxicity was assessed by measuring cell viability, membrane integrity, and reactive oxygen species (ROS) levels in model gastrointestinal cells (GES-1 and Caco-2). Additionally, mortality, deformity rate, heart rate and death of whole zebra fish embryos were measured. The five types of nano-SiO2 samples comprised amorphous particles with a purity of approximately 99%, which met the food additive standard. Considering that the original particle size ranged from 10 to 50 nm, the samples were classified as nano-SiO2 food additives. Nano-SiO2 did not significantly impact the activity of GES-1 or Caco-2 cells, and no significant cell membrane damage was observed (Caco-2 cells exhibited mild micro damage); however, a slight increase in intracellular RPS levels was detected. Moreover, nano-SiO2 was found to cause head deformity, pericardial edema, yolk sac edema and tail bending. Collectively, the results show that nano-SiO2 time- and dose-dependently affects GES-1 and Caco-2 cell viability, as well as the mortality, heart rate, and abnormality rate of zebra fish embryos. Specifically, a high concentration (≥ 200 μg/mL) and long exposure time (≥ 48 h) of food additive nano-SiO2 affected GES-1, Caco-2 cells, and the gastrointestinal tract in zebra fish embryos.

Toxicity of boron and vanadium nanoparticles on Danio rerio embryos - Phenotypical, biochemical, and behavioral alterations

Engineered nanoparticles (NPs) are emerging contaminants of concern and it is important to understand their environmental behavior and ecological risks to exposed organisms. Despite their ubiquitous presence in the environment, there is little information about the hazards of certain NPs, such as boron (BNPs) and vanadium (VNPs). The aim of the present research was to investigate the effects of commercial BNPs and VNPs (80 to 100 nm) to zebrafish embryos, at different levels of biological organization. A range of nominal concentrations for both NPs (0, 0.01, 0.1, 1, and 10 mg/L) was tested. Due to the presence of triton X-100 in the NPs' stock dispersions, an additional control group was included (0.001% triton X-100). Survival, hatching, and malformations of embryos were assessed for 96 hours (h) exposure. Locomotor behavior was evaluated at 120 h. Furthermore, embryos were exposed to 0, 1, and 10 mg/L of NPs to evaluate a set of biomarker responses after 96 h: cholinesterase (ChE) and glutathione S-transferase (GST) activities, total glutathione (TG) and energy budgets levels. VNPs induced malformations (10 mg/L), hyperactivity (10 mg/L), erratic swimming (0.01 mg/L), altered swimming pattern (>0.01 mg/L), delayed hatching (10 mg/L) and altered biochemical responses involved in antioxidant defense (GST and TG at >1 mg/L), neurotransmission (ChE at 10 mg/L) and energy metabolism (lipids at >1 mg/L and carbohydrates at 10 mg/L). BNPs caused malformations (10 mg/L), affected swimming pattern (>0.01 mg/L), induced erratic swimming (10 mg/L) and decreased TG content and GST activity (>1 mg/L). At the same concentrations, VNPs affected a greater number of endpoints than BNPs, demonstrating a greater toxicity to zebrafish embryos. The present study shows that BNPs and VNPs may affect aquatic organisms, albeit at relatively great non-environmentally relevant concentrations, reinforcing the importance of the risk assessment of different NPs.

Synthesis and characterization of palladium nanoparticles by chemical and green methods: A comparative study on hepatic toxicity using zebrafish as an animal model

Nanoparticles synthesized by chemical methods are of a matter of concern, whereas, the green methods are said to be eco-friendly and environmentally safe. In this study, the toxicity of palladium nanoparticles (Pd NPs) synthesized through chemical co-precipitation and green route method using Annona squamosa seed kernels (As-Pd NPs) were evaluated using zebrafish as an animal model. The synthesized nanoparticles (NPs) were characterized using UV-Visible spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray (EDX), Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS) and Zeta potential. Zebrafish (Danio rerio) were exposed to 0.4 ng/L of Pd NPs and As-Pd NPs for 96-h, further oxidative stress parameters and histological changes were evaluated. The superoxide dismutase (SOD), catalase (CAT) activity and the lipid peroxidation (LPO) levels were elevated in the Pd NPs groups. But in the As-Pd NPs group, the SOD activity showed a biphasic nature while the CAT activity gradually declined till the 96-h compared to the control and Pd NPs groups. The LPO levels in the As-Pd NPs groups showed a measurable increase till 72-h and sudden decline at the end of 96-h. Anomalies in the histological changes such as ruptured hepatocytes, sinusoidal congestion, vacuolation and accumulation of erythrocytes were observed in both the NPs treated groups but As-Pd NPs exhibited lesser lesions than the control and Pd NPs groups. However, our present study reveals the possible reliability of the nanoparticles and the mechanism of scavenging activity suggesting that the As-Pd NPs synthesized by green route are less toxic comparing to the chemically synthesized Pd NPs.

Adverse effects of amorphous silica nanoparticles: Focus on human cardiovascular health

Amorphous silica nanoparticle (SiNPs) has tremendous potential for a host of applications, while its mass production, broad application and environmental release inevitably increase the risk of human exposure. SiNPs could enter into the human body through different routes such as inhalation, ingestion, skin contact and even injection for medical applications. The cardiovascular system is gradually recognized as one of the primary sites for engineered NPs exerting adverse effects. Accumulating epidemiological or experimental evidence support the association between SiNPs exposure and adverse cardiovascular effects. However, this topic is still in its infancy, and the literature shows high inter-study variability and even contradictory results. New challenges still present in the safety evaluation of SiNPs, and its toxicological mechanisms are poorly understood. Here, scientific papers related to cardiovascular studies of SiNPs in vivo and in vitro were selected, and the updated particle-caused cardiovascular toxicity and potential mechanisms were summarized. Moreover, the understanding of how factors primarily including exposure dose, route of administration, particle size and surface properties, influence the interaction between SiNPs and cardiovascular system was discussed. In particular, the adverse outcome pathway (AOP) framework by which SiNPs cause deleterious effects in the cardiovascular system was described, aiming to provide useful information necessary for the regulatory decision and to guide a safer application of nanotechnology.

Hazardous Effects of SiO2 Nanoparticles on Liver and Kidney Functions, Histopathology Characteristics, and Transcriptomic Responses in Nile Tilapia (Oreochromis niloticus) Juveniles

Simple Summary

Waterborne exposure of Nile tilapia (Oreochromis niloticus) juveniles to sub-lethal concentrations of silicon dioxide nanoparticles (SiO₂NPs) induced hepato-renal damage through elevation of aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) activities as well as creatinine and blood urea levels. SiO₂NPs induced irreversible dose-dependent histopathological changes in the hepatopancreas, gills, and posterior kidneys, alongside modulation of the pro-inflammatory cytokines, apoptosis-related genes, and oxidative stress genes in gills and liver of exposed fish.

Abstract

The current investigation assessed the impacts of sub-lethal concentrations of silicon dioxide nanoparticles (SiO₂NPs) on hepato-renal functions, histopathological characteristics, and gene transcription in gills and liver of Nile tilapia juveniles. Fish were exposed to 20, 40, and 100 mg/L of SiO₂NPs for 3 weeks. Pairwise comparisons with the control group showed a significant dose-dependent elevation in serum ALP, ALT, and AST enzyme activities as well as blood urea and creatinine levels in SiO₂NP-intoxicated groups. Exposure to 100 mg/L SiO₂NPs significantly upregulated expression of HSP70, TNF-α, IL-1β, and IL-8 genes in the gills as compared to the control group. Moreover, exposure to 100 mg/L SiO₂NPs significantly upregulated the expression SOD, HSP70, IL-1β, IL-8, and TNF-α genes in the hepatic tissues as compared to the control group. Exposure of fish to 20 mg SiO₂NPs/L significantly increased the mRNA expression levels of IL-12 in both the gills and liver tissues. Notably, all tested SiO₂NP concentrations significantly upregulated the transcription of CASP3 gene in gills and liver of Nile tilapia as compared to the control group. Interestingly, varying histopathological alterations in renal, hepatopancreatic, and branchial tissues were observed to be correlated to the tested SiO₂NP concentrations. In conclusion, our results provide additional information on the toxic impacts of SiO₂NPs in Nile tilapia at the hematological, tissue, and molecular levels.

Synthetic Ligand-Coated Starch Magnetic Microbeads for Selective Extraction of Food Additive Silicon Dioxide from Commercial Processed Food

The amorphous form of silicon dioxide has long been regarded as a safe food additive (E551) that is widely used in commercially processed food as an anticaking agent. However, starting with titanium dioxide, there have been growing safety concerns regarding to the use of nanoscale silicon dioxide particles in food as food additives. The size, morphology, and chemical properties of inorganic food materials are important parameters to determine its potential toxicity. Therefore, an effective means of extracting an intact form of SiO₂ from food without altering the physicochemical property of SiO₂ particles is of great need to accurately monitor its characteristics. Here, we report on an effective magnetic separation method to extract food additive SiO₂ from food by utilizing a diatom-originated peptide with a specific affinity to SiO₂ particles. The affinity-based magnetic separation was found to be specific to SiO₂ particles over other types of inorganic food additives such as titanium dioxide and zinc oxide. The size and morphology of SiO₂ were shown to not be affected by the extraction processes. This method was successfully applied to extract and characterize the food additive SiO₂ from six different types of commercial food.

Effects of SiO2 nanoparticles on the uptake of tetrabromobisphenol A and its impact on the thyroid endocrine system in zebrafish larvae

The coexistence of nanoparticles and organic toxicants in the environment modifies pollutant bioavailability and toxicity. This study investigated the influence of silicon dioxide nanoparticles (n-SiO₂) on the uptake of tetrabromobisphenol A (TBBPA) and its impact on the thyroid endocrine system in zebrafish larvae. Zebrafish (Danio rerio) embryos were exposed to TBBPA at different concentrations (50, 100, and 200 μg/L) alone or in combination with n-SiO₂ (25 mg/L) until 120 h post-fertilization (hpf). Chemical measurements showed that both TBBPA and n-SiO₂ were bioconcentrated in zebrafish larvae, and the uptake of TBBPA was enhanced by n-SiO₂. Furthermore, zebrafish larvae exposed to 200 μg/L TBBPA alone exhibited significantly increased T4 contents and decreased T3 contents, whereas n-SiO₂ treatment alone did not have a detectable effect. Furthermore, the thyroid hormone levels changed more upon treatment with 200 μg/L TBBPA combined with 25 mg/L n-SiO₂ than upon TBBPA treatment alone. Alterations in gene transcription along the related hypothalamic-pituitary-thyroid (HPT) axis were observed, and expression of the binding and transport protein transthyretin (TTR) was significantly decreased for both TBBPA alone and co-exposure with n-SiO₂. Thus, the current study demonstrates that n-SiO₂, even at the nontoxic concentrations, increases thyroid hormone disruption in zebrafish larvae co-exposed to TBBPA by promoting its bioaccumulation and bioavailability.

Developmental neurotoxicity fingerprint of silica nanoparticles at environmentally relevant level on larval zebrafish using a neurobehavioral-phenomics-based biological warning method

BACKGROUND

Larval zebrafish (Danio rerio) is not only an ideal vertebrate applied in Fish Embryos Toxicity (FET) test but also a well-accepted model in behavioral neurotoxicity research. By applying the commercial standard behavioral tracking system (Zebrabox), the locomotion profiles (neurobehavioral-phenomics) of larval zebrafish can be comprehensively monitored and systematically analyzed to probe ecotoxicological neurotoxicity of nano-pollutants at environmental relevant concentration level.

RESULTS

Herein, the potential toxicity of at environment relevant concentration level on embryonic zebrafish was evaluated by FET and neurobehavioral-phenomics (NBP). The embryos were exposed to the environmental relevant concentration (0.05, 0.1,1, 5, 10, 100 μg/L). The FET criteria were utilized to evaluate the ecotoxicological effect induced by silica NPs. Subsequently, behavioral neurotoxicity of silica NPs was further quantified via locomotion response (LMR). Specifically, the alteration of Light/Dark challenge (LDC) evoked by light/dark stimulation was detected and analyzed by commercially standard behavioral protocols using zebrabox. We revealed that the exposures of silica NPs at environmental relevant concentration (0.05, 0.1, 1, 5, 10,100 μg/L) significantly disturbed locomotion profiles of larval zebrafish. Additionally, it was obviously noted that low, environmentally relevant silica concentrations might result in altering the total behavioral profiles in developing zebrafish.

CONCLUSIONS

In sum, neurobehavior phenomics profiling based on LMR and LDC is a potent methodology for the evaluation of sub-lethal or sub-teratogenic toxicity. Compared with the FET tests characterized by the detection of embryonic teratogenicity, the neurobehavior phenomics based method can be more sensitive to determine sub-teratogenic toxicity of silica NPs at environmental concentrations. With the combination of multivariate data analysis, this approach would offer effective technical reference for environmental nano-toxicology research.

The nano-bio interactions of rare-earth doped BaF2 nanophosphors shape the developmental processes of zebrafish

Nanoparticles with biomedical applications should be evaluated for their biocompatibility. Rare-earth doped nanoparticles with unique spectral properties are superior in vivo optical probes in comparison with quantum dots and organic dyes, however, studies describing their nano-bio interactions are still limited. Here, we have evaluated the nano-bio interactions of green-synthesized, phase-pure BaF₂ nanoparticles doped with rare-earth (RE³⁺ = Ce³⁺/Tb³⁺) ions using larval zebrafish. We found that zebrafish can tolerate a wide concentration range of these nanoparticles, as the maximal lethality was observed at very high concentrations (more than 200 mg L^-1) upon five days of continuous exposure. At a concentration of 10 mg L^-1, at which Zn²⁺, Ti⁴⁺ and Ag⁺ nanoparticles are reported to be lethal to developing zebrafish, continuous exposure to our nanoparticles for four days produced no developmental anomalies, craniofacial defects, cardiac toxicity or behavioural abnormalities in the developing zebrafish larvae. We have also found that the doping of rare-earth ions has no major effect on these biomarkers. Interestingly, the function of acetylcholinesterase (AChE) and the cellular metabolic activity of whole zebrafish larvae remained unchanged, even during continuous exposure to these nanoparticles at 150 mg L^-1 for four days; however, severe developmental toxicities were evident at this high concentration. Based on these results, we can conclude that the biocompatibility of rare-earth doped nanoparticles is concentration dependent. Not all biomarkers are sensitive to these nanoparticles. The high concentration-dependent toxicity occurs through a mechanism distinct from changes in the metabolic or AChE activity. The significance of these findings lies in using these nanoparticles for bioimaging applications and biomarker studies, especially for prolonged exposure times.

Comparative Acute Toxicity and Oxidative Stress Responses in Three Aquatic Species Exposed to Stannic Oxide Nanoparticles and Stannic Chloride

We experimentally investigated the toxicity of stannic oxide nanoparticles (SnO₂ NPs) to three freshwater species including Scenedesmus obliquus, Daphnia magna, and Danio rerio. To evaluate effect, toxicological impacts were compared to that of stannic chloride (SnCl₄). Based on the actual concentration of Sn, SnO₂ NPs suspensions inhibited growth of S. obliquus in a dose-dependent manner, demonstrating a median effect concentration of 2.28 ± 0.53 mg/L. However, SnO₂ NP suspensions were found to exhibit limited acute toxicity in D. magna and D. rerio. Moreover, the toxicity of the SnO₂ NP suspension was lower than SnCl₄ for all three trophic aquatic organisms. Comparison of component-specific contribution to overall toxicity indicated that, in SnO₂ NP suspensions, particulate Sn more significantly contributed to toxicity than dissolved Sn-ions. Furthermore, we found that the toxic mechanism of the SnO₂ NP suspension involved the induction of oxidative stress by increasing intracellular ROS accumulation.

A link between nanoparticles and Parkinson's disease. Which nanoparticles are most harmful?

Nowadays, different kinds of nanoparticles (NPs) are produced around the world and used in many fields and products. NPs can enter the body and aggregate in the various organs including brain. They can damage neurons, in particular dopaminergic neurons in the substantia nigra (SN) and striatal neurons which their lesion is associated with Parkinson's disease (PD). So, NPs can have a role in PD induction along with other agents and factors. PD is the second most common neurodegenerative disease in the world, and in patients, its symptoms progressively worsen day by day through different pathways including oxidative stress, neuroinflammation, mitochondrial dysfunction, α-synuclein increasing and aggregation, apoptosis and reduction of tyrosine hydroxylase positive cells. Unfortunately, there is no effective treatment for PD. So, prevention of this disease is very important. On the other hand, without having sufficient information about PD inducers, prevention of this disease would not be possible. Therefore, we need to have sufficient information about things we contact with them in daily life. Since, NPs are widely used in different products especially in consumer products, and they can enter to the brain easily, in this review the toxicity effects of metal and metal oxide NPs have been evaluated in molecular and cellular levels to determine potential of different kinds of NPs in development of PD.

Antagonistic effects of multi-walled carbon nanotubes and BDE-47 in zebrafish (Danio rerio): Oxidative stress, apoptosis and DNA damage

In natural environments, organisms are often exposed to several environmental pollutants at any one time, and the potential effects of such co-exposures on human and environmental health are of considerable concern. It is thought that multi-walled carbon nanotubes (MWCNTs) may interact with other pollutants in aquatic systems and induce considerably different effects compared with exposure to a single contaminant. The objective of this study was to evaluate the potential acute combined effects of mixtures of MWCNTs and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on embryonic development stages, oxidative stress, apoptosis and DNA damage in developing zebrafish (Danio rerio). The embryos were treated with BDE-47 (5, 10, and 50 μg/L) and MWCNTs (50 mg/L), either combined or individually, for 96 h. Following exposure, BDE-47 induced significant acute toxicity, while the MWCNTs exhibited slight toxicity. When compared with BDE-47-only exposure, the inhibited growth induced by BDE-47 was weakened in the presence of MWCNTs. Similarly, the levels of oxidative stress biomarkers (reactive oxygen species, superoxide dismutase, catalase activities and malondialdehyde), apoptosis (apoptosis rate, caspase-3 and caspase-9 activities) and DNA damage (comet assay and comet olive tails) decreased in the presence of MWCNTs compared to those exposed to BDE-47 alone. These results demonstrate that MWCNTs can weaken the developmental inhibition, oxidative stress, apoptosis and DNA damage induced by BDE-47 in the early stages of zebrafish development.

Mesoporous Silica Nanoparticles at Predicted Environmentally Relevant Concentrations Cause Impairments in GABAergic Motor Neurons of Nematode Caenorhabditis elegans

Available safety evaluations regarding mesoporous silica nanoparticles (mSiNPs) are based on the assumption of a relatively high exposure concentration, which makes the findings less valuable in a realistic environment. In this study, we employed Caenorhabditis elegans (C. elegans) as a model to assess the neuronal damage caused by mSiNPs at the predicted environmentally relevant concentrations. After nematodes were acute and prolonged exposed to mSiNPs at concentrations over 300 μg/L, locomotion degeneration, shrinking behavior, and abnormal foraging behavior were observed, which were associated with the deficits in the development of GABAergic neurons, including D-type and RME motor neurons. Furthermore, the oxidative stress evidenced by excessive ROS generation might contribute to the mechanism of mSiNPs damaging neurons. Although the neurotoxicity of mSiNPs was weaker than (nonmesoporous) SiNPs, it is still necessary for researchers to pay attention to the adverse effects caused by mSiNPs in the environmental animals, especially with the rapid increase in mSiNPs application. Considering the conserved property of GABAergic neurons during evolution, these findings will shed light on our understanding of the potential eco-risks of NPs to the nervous system of other animal models.

Nanotechnology-based Drug Delivery, Metabolism and Toxicity

BACKGROUND

Nanoparticles (NPs) are being used extensively owing to their increased surface area, targeted delivery and enhanced retention. NPs have the potential to be used in many disease conditions. Despite widespread use, their toxicity and clinical safety still remain a major concern.

OBJECTIVE

The purpose of this study was to explore the metabolism and toxicological effects of nanotherapeutics.

METHODS

Comprehensive, time-bound literature search was done covering the period from 2010 till date. The primary focus was on the metabolism of NP including their adsorption, degradation, clearance, and bio-persistence. This review also focuses on updated investigations on NPs with respect to their toxic effects on various in vitro and in vivo experimental models.

RESULTS

Nanotechnology is a thriving field of biomedical research and an efficient drug delivery system. Further their applications are under investigation for diagnosis of disease and as medical devices.

CONCLUSION

The toxicity of NPs is a major concern in the application of NPs as therapeutics. Studies addressing metabolism, side-effects and safety of NPs are desirable to gain maximum benefits of nanotherapeutics.

Silica nanoparticles induce JNK-mediated inflammation and myocardial contractile dysfunction

Increasing environmental exposure to silica nanoparticles (SiNPs) and limited cardiotoxicity studies posed a challenge for the safety evaluation and management of these materials. This study aimed to explore the adverse effects and underlying mechanisms of subacute exposure to SiNPs on cardiac function in rats. Results from echocardiographic, ultrastructural and histopathological analysis found that SiNPs induced cardiac contractile dysfunction, accompanied by incomplete myocardial structures, disordered sarcomere segments, interstitial edema and myocyte apoptosis in heart. Levels of myocardial enzymes and inflammatory factors were markedly increased in both serum and heart tissue, accompanied by elevated levels of oxidative damage occurred in the hearts of SiNPs-treated rats. SiNPs significantly upregulated the expressions of inflammation and contraction-related proteins, including JNK, p-JNK, c-Jun, TF and PAR1. Lentivirus transfection of JNK shRNA showed the low-expression of JNK-facilitated F-actin and inhibited TF in the SiNPs-treated cardiomyocytes. Moreover, SiNPs activated the mRNA and protein levels of JNK/TF/PAR1 pathway, and these effects were significantly dampened after JNK knock down. Our results demonstrate that SiNPs trigger myocardial contractile dysfunction via JNK/TF/PAR1 signaling pathway.

Combined toxic effects of fludioxonil and triadimefon on embryonic development of zebrafish (Danio rerio)

Pesticides scarcely exist as individual compounds in the water ecosystem, but rather as mixtures of multiple chemicals at relatively low concentrations. In this study, we aimed to explore the mixture toxic effects of fludioxonil (FLU) and triadimefon (TRI) on zebrafish (Danio rerio) by employing different toxicological endpoints. Results revealed that the 96-h LC₅₀ values of FLU to D. rerio at multiple developmental stages ranged from 0.055 (0.039-0.086) to 0.61 (0.33-0.83) mg L^-1, which were less than those of TRI ranging from 3.08 (1.84-5.96) to 9.75 (5.99-14.78) mg L^-1. Mixtures of FLU and TRI exerted synergistic effects on embryonic zebrafish. Activities of total superoxide dismutase (T-SOD) and catalase (CAT) were markedly altered in most of the individual and pesticide mixture treatments compared with the control. The expressions of 16 genes involved in oxidative stress, cellular apoptosis, immune system and endocrine system displayed that embryonic zebrafish were affected by the individual pesticides and their mixtures, and greater variations of four genes (ERɑ, Tnf, IL and bax) were found when exposed to pesticide mixtures compared with their individual compounds. Therefore, more studies on mixture toxicities among different pesticides should be taken as a priority when evaluating their ecological risk.

Comparative Assessment of Genotoxic Impacts Induced by Zinc Bulk- and Nano-Particles in Nile tilapia, Oreochromis niloticus

Fish were separately exposed to 1/2 LC50/96 h values of bulk-Zn and nano-Zn for 7, 14, and 28 days. The induction of micronuclei (MN) and other eight nuclear abnormalities in erythrocytes showed marked time and size dependence. The frequencies of all nuclear anomalies were progressively elevated (p < 0.05) with increasing the time of exposure to both bulk-Zn and nano-Zn. Throughout the study periods, fish exposed to nano-Zn showed the maximum elevation in all studied nuclear anomalies. Based on the fragmented DNA values, both Zn forms induced tissue-specific DNA damage as following gills > liver > muscles. Moreover, nano-Zn exposed groups revealed a maximum percentage of DNA damage among all studied groups, especially after 14 days. The percentage of DNA damage was decreased in all tissues on the 28th day, which reflected the presence of an effective repair mechanism. Finally, nano-Zn exhibited more genotoxic effects than that of its bulk counterparts.