ZnO NPs Exposure Research Articles

ZnO NPs induce miR-342-5p mediated ferroptosis of spermatocytes through the NF-κB pathway in mice

BackgroundZinc oxide nanoparticle (ZnO NP) is one of the metal nanomaterials with extensive use in many fields such as feed additive and textile, which is an emerging threat to human health due to widely distributed in the environment. Thus, there is an urgent need to understand the toxic effects associated with ZnO NPs. Although previous studies have found accumulation of ZnO NPs in testis, the molecular mechanism of ZnO NPs dominated a decline in male fertility have not been elucidated.ResultsWe reported that ZnO NPs exposure caused testicular dysfunction and identified spermatocytes as the primary damaged site induced by ZnO NPs. ZnO NPs led to the dysfunction of spermatocytes, including impaired cell proliferation and mitochondrial damage. In addition, we found that ZnO NPs induced ferroptosis of spermatocytes through the increase of intracellular chelatable iron content and lipid peroxidation level. Moreover, the transcriptome analysis of testis indicated that ZnO NPs weakened the expression of miR-342-5p, which can target Erc1 to block the NF-κB pathway. Eventually, ferroptosis of spermatocytes was ameliorated by suppressing the expression of Erc1.ConclusionsThe present study reveals a novel mechanism in that miR-342-5p targeted Erc1 to activate NF-κB signaling pathway is required for ZnO NPs-induced ferroptosis, and provide potential targets for further research on the prevention and treatment of male reproductive disorders related to ZnO NPs.Graphical

Protective potential of fresh orange juice against zinc oxide nanoparticles-induced trans-placental and trans-generational toxicity in mice.

Due to the emerging applications of nanoparticles, human exposure to nanoparticles is unavoidable, particularly to zinc oxide nanoparticles (ZnO NPs), owing to their wide range of usage. The ongoing study aimed to evaluate trans-generational toxic potential of ZnO NPs through exposure to F0 mothers, in F1 pups and F1 mature offspring and the protective potential of fresh orange juice (OJ). Twenty-eight F0 mothers were randomly allocated into four groups (n = 7), control; untreated, dose group; exposed to ZnO NPs, dose+antidote group; coadministered ZnO NPs + OJ, antidote group; OJ, during the organogenetic period. Fifty percent of F0 mothers were subjected to cesarean sections on the 18th day of gestation and F1 pups were recovered, macro-photographed, and dissected for liver evisceration, while 50% of F0 mothers underwent standard delivery. After parturition, F1 offspring were examined, and the liver and blood samples were extracted. Observations showed that ZnO NPs exposure in F0 mothers in preparturition and postparturition resulted in decreased body weight, increased liver weight, and elevated levels of ALT and AST significantly p ≤ .05 as compared to the control and antidote groups. Histopathological analysis of maternal livers intoxicated with NPs showed the disruptive structure of central vein, hepatocytes, and Kupffer cells in F0 mothers, while F1 pups showed morphological deviations and distorted development of the liver tissue and congestion, in contrast to the control. F1 offspring of NPs exposed mothers, even at postnatal week 8 showed pyknotic nuclei and activated Kupffer cells in the liver sections against control. But in the case of the Dose+antidote group, alterations were less severe than in the dose group. It can be concluded that exposure to ZnO NPs instigates teratogenicity and hepatotoxicity in F1 pups, F0 mothers, and F1 offspring, respectively, while fresh orange juice acts as a remedial agent against the abovementioned toxicities.

Mitigation mechanism of zinc oxide nanoparticles on cadmium toxicity in tomato.

Cadmium (Cd) pollution seriously reduces the yield and quality of vegetables. Reducing Cd accumulation in vegetables is of great significance for improving food safety and sustainable agricultural development. Here, using tomato as the material, we analyzed the effect of foliar spraying with zinc oxide nanoparticles (ZnO NPs) on Cd accumulation and tolerance in tomato seedlings. Foliar spraying with ZnO NPs improved Cd tolerance by increasing photosynthesis efficiency and antioxidative capacity, while it reduced Cd accumulation by 40.2% in roots and 34.5% in leaves but increased Zn content by 33.9% in roots and 78.6% in leaves. Foliar spraying with ZnO NPs also increased the contents of copper (Cu) and manganese (Mn) in the leaves of Cd-treated tomato seedlings. Subsequent metabonomic analysis showed that ZnO NPs exposure alleviated the fluctuation of metabolic profiling in response to Cd toxicity, and it had a more prominent effect in leaves than in roots. Correlation analysis revealed that several differentially accumulated metabolites were positively or negatively correlated with the growth parameters and physiol-biochemical indexes. We also found that flavonoids and alkaloid metabolites may play an important role in ZnO NP-alleviated Cd toxicity in tomato seedlings. Taken together, the results of this study indicated that foliar spraying with ZnO NPs effectively reduced Cd accumulation in tomato seedlings; moreover, it also reduced oxidative damage, improved the absorption of trace elements, and reduced the metabolic fluctuation caused by Cd toxicity, thus alleviating Cd-induced growth inhibition in tomato seedlings. This study will enable us to better understand how ZnO NPs regulate plant growth and development and provide new insights into the use of ZnO NPs for improving growth and reducing Cd accumulation in vegetables.

Selenium improves the histochemical pattern of amyloid beta proteins and carbohydrates in cerebellum of rats after ZnO NPs exposure.

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Sub-chronic Effects of Zinc oxide Nanoparticles on Ovary, Gills, Kidney and Liver of Fresh Water Fish (Cyprinus carpio): histopathological Study

Concerns have been raised about the potential environmental dangers connected with ZnO nanoparticles (ZnO NPs) entering aquatic systems due to the growing use of ZnO NPs in various fields. This study looked about how freshwater fish (Cyprinus carpio) respond to sub-chronic exposure to ZnO NPs through food. Common carp (C. carpio) from nearby fish hatcheries were employed in this investigation (city of Madaan, south of Baghdad). These fish had an approximate length and weight of 15-18 cm and 120-5 gram, respectively. Once every day, fish fed commercial fish meal. They were acclimated in 40 L aquariums (60 x 40 x 50 cm) with continuous aeration and 16- and 8-hours photoperiod for 12 days prior to the commencement of the experiment. For six weeks, two groups of fishes were treated to doses of 250 and 500 mg/l. Samples were taken six weeks after the ZnO NPs exposure. Five fish from every ZnO NPs treated group as well as the associated controls were taken out, killed, and preserved in formalin after necessary exposure times for tissue samples (liver, gills, kidney, and ovaries). The tissues samples exhibit pathological changes as a result, particularly at concentrations of 500 mg/l of Zinc oxide nanoparticles.

Vitamins A, C, and E Exert Anti-apoptotic Function in the Testis of Rats After Exposure to Zinc Oxide Nanoparticles.

Some reports emphasize that zinc oxide nanoparticles (ZnO NPs) are detrimental to the reproductive organs of animals. As such, this research aimed at exploring the apoptotic potential of ZnO NPs on testis along with the beneficial role of Vitamins (V) A, C, and E against ZnO NP-induced damage. To this aim, a population of 54 healthy, male Wistar rats were used in this work and then assigned into nine groups of 6 rats as G1: Control 1 (Water); G2: Control 2 (Olive oil); G3: VA (1000 IU/kg), G4: VC (200 mg/kg), G5: VE (100 IU/kg), G6: ZnO NPs exposed animals (200 mg/kg); and G7, 8 and 9: ZnO NPs-exposed animals that were pre-treated with either VA, C, or E. Apoptosis rates were estimated by measuring the level of apoptotic regulatory markers including Bcl-2-associated X (Bax) and B-cell lymphoma protein 2 (Bcl-2) using western blotting and qRT-PCR assays. The data indicated that ZnO NPs exposure elevates the level of Bax protein and gene expression, whereas the protein and gene expression of Bcl-2 was reduced. Further, the activation of caspase-3,7 occurred after exposure to ZnO NPs, while the above alterations were significantly alleviated in the rats that were co-treated with VA, C, or E and ZnO NPs relative to the rats in the ZnO NPs group. In summary, VA, C, and E exerted anti-apoptotic functions in the testis of rats following administration of ZnO NPs.

Multiple generation exposure to ZnO nanoparticles induces loss of genomic integrity in Caenorhabditis elegans

Zinc oxide nanoparticles (ZnO NPs) are commonly used in industrial and household applications, prompting the assessment of their associated health risks. Previous studies indicated that ZnO NPs can induce somatic cell mutations, while the aging process appears to increase the mutagenicity of ZnO NPs. However, little is known about the influence of ZnO NPs on genome stability of germ cells, and non-exposed progeny. Here we show that 20 nm ZnO NPs exposure disrupts germ cell development, and elevates the overall mutation frequency of germ cells in Caenorhabditis elegans (C. elegans). We observed that pristine ZnO NPs elicit germ cell apoptosis to a greater extent than the 60-day aged ZnO NPs. By treating parental worms with ZnO NPs for seven successive generations, whole-genome sequencing data revealed that, although the frequency of point mutations is kept unchanged, large deletions are significantly increased in F8 worms. Furthermore, we found that the mutagenicity of ZnO NPs might be partially attributed to the release of Zn2+ ions. Together, our results demonstrate the genotoxic effects of ZnO NPs on germ cells, and the possible underlying mechanism. These findings suggest that germ cell mutagenicity is worthy of consideration for the health risk assessment of engineered NPs.

The interplay of calponin, wnt signaling, and cytoskeleton protein governs transgenerational phenotypic abnormalities in drosophila exposed to zinc oxide nanoparticles

ZnO nanoparticles (ZnO NPs) are widely used engineered nanomaterials. Due to induced genotoxicity, increased oxidative stress, and teratogenicity, these NPs have been reported to be toxic. In the present study, we emphasise the role of vital proteins in regulating ZnO NP-induced abnormal phenotypes, particularly the deformed thorax and single wing in the Drosophila melanogaster progeny fed on 0.1–10 mM ZnO NPs. To understand how protein expression regulates this particular phenotype on ZnO NPs exposure, toxicoproteomics profile of control and abnormal phenotype flies was generated using LC/MS/MS. Gene ontology enrichment studies of proteomics data were carried out using CLUEGO and STRAP software. The bioinformatics tool STRING was used to generate a protein–protein interaction map of key proteins of enrichment analysis. Following ZnO NP exposure, the differential expression of key proteins of the Wnt pathway was prominent. Altered expression of various proteins of the Wnt pathway (CaMKII), cytoskeleton (Actin), and calponin resulted in developmental defects in drosophila progeny. In addition, immunohistology studies showed a significant deviation in the expression of wingless protein of ZnO NPs treated larvae in comparison to control. According to these findings, the interaction of the wnt pathway and cytoskeletal proteins with ZnO NPs caused developmental abnormalities in the subsequent generation of drosophila, highlighting the transgenerational toxic effects of these nanoparticles.

Different Strategies to Attenuate the Toxic Effects of Zinc Oxide Nanoparticles on Spermatogonia Cells.

Zinc oxide nanoparticles (ZnO NPs) are one of the most used nanoparticles due to their unique physicochemical and biological properties. There is, however, a growing concern about their negative impact on male reproductive health. Therefore, in the present study, two different strategies were used to evaluate the recovery ability of spermatogonia cells from the first stage of spermatogenesis (GC-1 spg cell line) after being exposed to a cytotoxic concentration of ZnO NPs (20 µg/mL) for two different short time periods, 6 and 12 h. The first strategy was to let the GC-1 cells recover after ZnO NPs exposure in a ZnO NPs-free medium for 4 days. At this phase, cell viability assays were performed to evaluate whether this period was long enough to allow for cell recovery. Exposure to ZnO NPs for 6 h and 12 h induced a decrease in viability of 25% and 41%, respectively. However, the recovery period allowed for an increase in cell viability from 16% to 25% to values as high as 91% and 84%. These results strongly suggest that GC-1 cells recover, but not completely, given that the cell viability does not reach 100%. Additionally, the impact of a synthetic chalcone (E)-3-(2,6-dichlorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (1) to counteract the reproductive toxicity of ZnO NPs was investigated. Different concentrations of chalcone 1 (0–12.5 µM) were used before and during exposure of GC-1 cells to ZnO NPs to mitigate the damage induced by NPs. The protective ability of this compound was evaluated through viability assays, levels of DNA damage, and cytoskeleton dynamics (evaluating the acetylated α-tubulin and β-actin protein levels). The results indicated that the tested concentrations of chalcone 1 can attenuate the genotoxicity induced by ZnO NPs for shorter exposure periods (6 h). Chalcone 1 supplementation also increased cell viability and stabilized the microtubules. However, the antioxidant potential of this compound remains to be elucidated. In conclusion, this work addressed the main cytotoxic effects of ZnO NPs on a spermatogonia cell line and analyzed two different strategies to mitigate this damage, which represent a significant contribution to the field of male fertility.

Different cellular mechanisms from low- and high-dose zinc oxide nanoparticles-induced heart tube malformation during embryogenesis

With the wide application of nanometer materials in daily life, people pay more attention to the potential toxicity of nanoparticles to human fetal development once the nanoparticles are absorbed into the human body during pregnancy. However, there was no directly solid evidence for ZnO NPs-caused congenital heart defects. Hence, we investigated the effect of ZnO NPs exposure on early cardiogenesis using the chicken/mouse embryo models. First, we showed ZnO NPs reduced H9c2 cell viability in a dose- and time-dependent manner, while cell autophagy was significantly activated too on the same pattern. During early cardiogenesis, ZnO NPs exposure increased the chance of heart tube malformation, while precardiac cell apoptosis rises in the phenotype of closure defect and Bifida. The hypertrophy was also observed in late-stage chicken/mouse survival embryos exposed to ZnO NPs. Apart from cell apoptosis, high-dose ZnO NPs exposure led to massive programmed necrosis, and further experiments verified that ferroptosis remained primarily in ZnO NPs-induced programmed necrosis. We also revealed that the toxicology of low-dose ZnO NPs was mainly featured in the changes of expressions of key genes instead of causing precardiac cell death. MYL2 and CSRP3 could work as the downstream molecules of the above key genes in the context of ZnO NPs exposure to early cardiogenesis based on RNA sequencing. Taken together, this study for the first time revealed the potential risk of heart tube malformation induced by ZnO NPs exposure through different cellular mechanisms, which depended on low- or high-dose ZnO NPs.

Evaluation of the Effects of Ag, Cu, ZnO and TiO2 Nanoparticles on the Expression Level of Oxidative Stress-Related Genes and the Activity of Antioxidant Enzymes in Escherichia coli, Bacillus cereus and Staphylococcus epidermidis.

Although the molecular response of bacteria exposed to metal nanoparticles (NPs) is intensively studied, many phenomena related to their survival, metal uptake, gene expression and protein production are not fully understood. Therefore, this work aimed to study Ag-NPs, Cu-NPs, ZnO-NPs and TiO2-NPs-induced alterations in the expression level of selected oxidative stress-related genes in connection with the activity of antioxidant enzymes: catalase (CAT), peroxidase (PER) and superoxide dismutase (SOD) in Escherichia coli, Bacillus cereus and Staphylococcus epidermidis. The methodology used included: the extraction of total RNA and cDNA synthesis, the preparation of primers for selected housekeeping and oxidative stress genes, RT-qPCR reaction and the measurements of CAT, PER and SOD activities. It was established that the treatment of E. coli and S. epidermidis with NPs resulted mainly in the down-regulation of targeted genes, whilst the up-regulation of genes was confirmed in B. cereus. The greatest differences in the relative expression levels of tested genes occurred in B. cereus and S. epidermidis treated with TiO2-NPs, while in E. coli, they were observed under ZnO-NPs exposure. The changes found were mostly related to the expression of genes encoding proteins with PER and CAT-like activity. Among NPs, ZnO-NPs and Cu-NPs increased the activity of antioxidants in E. coli and B. cereus. In turn, TiO2-NPs had a major effect on enzymes activity in S. epidermidis. Considering all of the collected results for tested bacteria, it can be emphasised that the impact of NPs on the antioxidant system functioning was dependent on their type and concentration.

Transcriptomics uncover the response of an aerobic denitrifying bacteria to zinc oxide nanoparticles exposure

ABSTRACT Zinc oxide nanoparticles (ZnO NPs) show adverse impacts on aerobic denitrifying bacteria, little is known about the response of these bacteria to ZnO NPs exposure at cellular level. This study assessed the multiple responses of Pseudomonas aeruginosa PCN-2 under ZnO NPs exposure. We demonstrated that ZnO NPs exposure could inhibit the intracellular metabolism and stimulate the antioxidant defence capability of PCN-2. At lower exposure concentration (5 mg/L), exogenous ROS generated and resulted in the inhibition of pyruvate metabolism and citrate cycle, which caused deficient energy for aerobic denitrification. At higher concentrations (50 mg/L), endogenous ROS additionally generated and triggered to stronger down-regulation of oxidative phosphorylation, which caused suppressed electron transfers for aerobic denitrification. Meanwhile, ZnO NPs exposure promoted EPS production and biofilm formation, and antioxidases was especially particularly stimulated at higher concentration. Our findings are significant for understanding of microbial bacterial susceptibility, tolerance and resistance under the exposure of ZnO NPs.

Skin damage induced by zinc oxide nanoparticles combined with UVB is mediated by activating cell pyroptosis via the NLRP3 inflammasome\u2013autophagy\u2013exosomal pathway

BackgroundZinc oxide nanoparticles (ZnONPs) are widely used nanomaterial in personal cosmetics, such as skin creams and sunscreens, due to their whitening properties and strong UV light absorption. However, the safety issues and the hazards of ZnONPs, which can be taken up by the skin and cause skin toxicity, are still unclear. From a chemoprevention point of view, pterostilbene (PT) has been reported to prevent skin damage effectively by its anti-inflammatory and autophagy inducer effect. This study aims to determine the skin toxicity and the potential mechanisms of UVB and ZnONPs exposure and the preventive effect of PT.ResultsThe co-exposure of UVB and ZnONPs elicit NLRP3 inflammasome activation and pyroptosis in keratinocytes. Furthermore, exposure to both UVB and ZnONPs also disrupts cellular autophagy, which increases cell exosome release. In vivo UVB and ZnONPs exposure triggers skin toxicity, as indicated by increased histological injury, skin thickness and transepidermal water loss. Notably, the NLRP3 inflammasome-mediated pyroptosis are also activated during exposure. Topical application of pterostilbene attenuates NLRP3 inflammasome activation and pyroptosis by decreasing ROS generation and mitochondrial ROS (mtROS) levels. In addition to its antioxidant effect, PT also reversed autophagy abnormalities by restoring normal autophagic flux and decreasing NLRP3 inflammasome-loaded exosome release.ConclusionsOur findings reveal that ZnONPs induce skin damage in conjunction with UVB exposure. This process involves an interplay of inflammasomes, pyroptosis, autophagy dysfunction, and exosomes in skin toxicity. PT alleviates skin inflammation by regulating the inflammasome–autophagy–exosome pathway, a finding which could prove valuable when further evaluating ZnONPs effects for cosmetic applications.

Bio-functionalized zinc oxide nanoparticles: Potential toxicity impact on freshwater fish Cyprinus carpio

There is a growing concern nowadays over the exposure of nanomaterials and their effects in aquatic life. In spite of reporting the changes in physiology, reproduction and behaviour in fish by different nanoparticles, the molecular events underlying in the aquatic bodies due to the toxicity of zinc oxide nanoparticles (ZnO NPs) are mainly unexplored. Therefore, the present study carried out an ex vivo exposure of ZnO NPs at various concentrations (0.382, 0.573 and 1.146 mg L−1) in freshwater fish Cyprinus carpio to investigate the potential adverse effects. The results revealed that ZnO NPs exposure altered the haematological parameter and induces the reactive oxygen species (ROS) that leads to elevation of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidise (GPx), glutathione S-transferase (GST) and reduced glutathione (GSH) activity in C. carpio. Furthermore, histopathological analysis exhibited that the ZnO NPs caused lamellar fusion, aneurism, cytoplasmic vacuolation, nuclear alteration, necrotic muscle fiber and pyknotic nuclei in the gills, liver and muscles of C. carpio. ZnO NPs exposure significantly up-regulated the overlapping expressions of SOD1, CAT, GPx1a, GST-α, CYP1A, and Nrf-2 genes. A higher level of Zn bioaccumulation was observed in the following order: gill (35.03 ± 2.50 μg g−1), liver (5.33 ± 0.73 μg g−1) and muscle (2.30 ± 0.20 μg g−1) at 1.146 mg L−1 exposure of ZnO NPs. Hence, the current study indicated that the biogenic ZnO NPs generate toxicity in fishes by modifying the antioxidant defense mechanisms, histomorphology, and oxidative stress encoding genes.

Ribosome profiling reveals translatome remodeling in cancer cells in response to zinc oxide nanoparticles.

The anticancer effect of zinc oxide nanoparticles (ZnO NPs) largely relies on cellular responses such as alteration of gene expression. Although ZnO NPs have been reported to induce transcriptional changes, the potential of ZnO NPs to affect cellular translatome remains largely unknown. Using ribosome profiling, we demonstrated that the transcription of 78 genes and the translation of 1,448 genes are affected during one hour of ZnO NPs exposure in A549 human lung cancer cells. The mitogen-activated protein kinase (MAPK) pathway is up-regulated upon ZnO NP treatment. The upstream open reading frame (uORF) plays a pervasive role in the induction of up-regulated genes, including TLNRD1 and CCNB1IP1. Knockdown of TLNRD1 or CCNB1IP1 reduces ZnO NP-induced cytotoxicity. Together, our study characterizes the landscape of translational alteration under ZnO NPs treatment and provides potential targets to augment the anticancer effect of ZnO NPs.

Inflammatory response in human alveolar epithelial cells after TiO2 NPs or ZnO NPs exposure: Inhibition of surfactant protein A expression as an indicator for loss of lung function

The increasing use of metal oxide nanoparticles (MONPs) as TiO2 NPs or ZnO NPs has led to environmental release and human exposure. The respiratory system, effects on lamellar bodies and surfactant protein A (SP-A) of pneumocytes, can be importantly affected. Exposure of human alveolar epithelial cells (A549) induced differential responses; a higher persistence of TiO2 in cell surface and uptake (measured by Atomic Force Microscopy) and sustained inflammatory response (by means of TNF-α, IL-10, and IL-6 release) and ROS generation were observed, whereas ZnO showed a modest response and low numbers in cell surface. A reduction in SP-A levels at 24 h of exposure to TiO2 NPs (concentration-dependent) or ZnO NPs (the higher concentration) was also observed, reversed by blocking the inflammatory response (by the inhibition of IL-6). Loss of SP-A represents a relevant target of MONPs-induced inflammatory response that could contribute to cellular damage and loss of lung function.

Aerobic sludge digestion is distinguishingly affected by the different entering pathways of zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO NPs) are widespread emerging pollutants raising global concerns about their influences on biological wastewater treatment processes. However, the impacts of ZnO NPs on aerobic sludge digestion that is a major sludge treatment process remain unknown. Herein, this study comprehensively investigated the key influences of ZnO NPs on aerobic digestion of waste activated sludge (WAS) and the potential mechanisms involved. Two different entering pathways, i.e., ZnO NPs directly entered into aerobic sludge digester and ZnO NPs initially entered into wastewater bio-treatment reactor, were tested to evaluate the different impacts. Compared to the control, ZnO NPs initially entering into wastewater bioreactor inhibited WAS degradation by 18.2 ± 0.1%, whereas ZnO NPs immediately entered into digester inhibited it by 29.7 ± 0.1%. This was accompanied by a similar decrease in inorganic nitrogen production and oxygen consumption. ZnO NPs exposure in wastewater bioreactor changed WAS characteristics in favor of solubilization in aerobic digestion. Modelling analysis indicated that ZnO NPs inhibited WAS hydrolysis, especially for their direct entering into aerobic digester. Correspondingly, microbial community was shifted in the direction against aerobic digestion by the ZnO NPs. Excessive oxidative stress and Zn2+ release represented the primary toxicity factors for the inhibition.

Endoplasmic reticulum stress-related calcium imbalance plays an important role on Zinc oxide nanoparticles-induced failure of neural tube closure during embryogenesis

Zinc oxide nanoparticles (ZnO NPs) have been increasingly and widely utilized in various fields, such as agriculture, food and cosmetics. However, various levels of adverse impacts of ZnO NPs on the ecological environment and public health have been associated with each stage of their production, use and disposal. ZnO NPs can be ingested by pregnant women and transferred to developing embryos/foetus through the placental barrier, however, the potential toxicity of ZnO NPs to embryonic and foetal development is largely unclear. In this study, we discovered that ZnO NPs exposure caused growth proportional failure of neural tube closure in mouse and chicken embryos and a simultaneous increase in apoptosis in the developing neural tubes of chicken embryos, which was verified in an in vitro experiment using the SH-SY5Y cell line. Furthermore, removal of free Zn2+ ions with EDTA or inhibition of Zn2+ ion absorption by CaCl2 partially alleviated the neurotoxicity induced by ZnO NPs, implying that ZnO NPs-induced developmental neurotoxicity is probably due to both ZnO NPs and the Zn2+ ions released from ZnO NPs. In addition, we found that ZnO NPs exposure caused endoplasmic reticulum stress-mediated apoptosis driven mainly by an increase in intracellular calcium (Ca2+) concentrations, rather than by the activation of three membrane protein receptors (ATF6, IRE-1 and PERK). Thus, Ca2+ imbalance-mediated apoptosis in the context of ZnO NPs exposure may lead to cellular dysfunctions in developing neural precursors, such as, abnormalities involved in neural tube closure, ultimately leading to neural tube defects (NTDs) during embryogenesis. In sum, our results revealed that ZnO NPs exposure greatly increases the risk of failure of neural tube closure through endoplasmic reticulum stress-mediated neural cell death in the developing embryos, which may further lead to the NTD in fetal stage, including failure of neural tube closure.

Bioaccumulation and toxicokinetics of zinc oxide nanoparticles (ZnO NPs) co-exposed with graphene nanosheets (GNs) in the blackfish (Capoeta fusca)

In this study, we investigated the bioaccumulation and toxicokinetics of zinc oxide nanoparticles (ZnO NPs) alone and in the presence of graphene nanosheets (GNs) in the blackfish (Capoeta fusca). Blackfish were exposed via water to two ZnO NPs concentrations alone or as a combination with GNs and uptake of Zn into the gills, intestine, liver, and kidney was assessed at 7, 14 and 28 d. Zn elimination from these tissues was then assessed after a further 7, 14 and 28 d in clean water for both ZnO NPs concentrations and combined ZnO NPs/GN exposures. In the body tissues analyzed of exposed fish, the highest amounts of Zn occurred in the intestine and the lowest amount in the liver. Zn levels in blackfish after 28 d of exposure were higher in all treatment groups compared to those on 7 d (p < 0.05). For both ZnO NPs exposure concentrations, the highest amount of Zn was eliminated from the intestine, followed by the gills. Furthermore, elimination kinetics for both ZnO NPs concentrations alone and in combination with GNs showed that the shortest half-life for Zn is occurring in the intestine. Moreover, uptake rates of Zn in fish exposed to ZnO NPs + GNs followed the same pattern observed for the ZnO NP, with intestine and gills having the highest levels followed by kidney and liver. Thus, we show accumulation and elimination of Zn from ZnO NPs in blackfish depends on the tissue, exposure concentration and duration, and is dependent on the presence of GNs.

Protein Profile of Human Lung Epithelial Cells (A549) Revealing Deviation in Cytoskeleton Proteins in Response to Zinc Oxide Nanoparticles Exposure

Zinc oxide nanoparticles (ZnO NPs) are widely used in biomedicine and scientific research because of their high dissolution property and bioavailability. On the contrary, this property also increases the intracellular reactivity, accessibility and cytotoxicity. These nano-bio interactions could induce undesirable changes in the proteome of the interacting cells, especially in the lung cells as these are the primary contact site. However, the potential effects of ZnO NPs exposure on proteome remain unclear. Proteomics data will substantiate the detailed mechanism of cellular interactions and modulatory effects of ZnO NPs on cells. Quantitative proteomic profiling was done using MALDI-TOF/TOF and MS/MS to identify differential protein expression on exposure to NPs among non exposed and exposed cells. Twenty-two proteins, with approximately 1.5 fold differential expression in cells exposed to ZnO NPs as compared to control cells were identified. Differentially expressed proteins were further classified using PANTHER software on the basis of functional gene ontology term: molecular function, biological process and cellular component. ToppGene suite was used to study protein-protein interaction and network was enriched with STRING. This study is a systematic analysis of protein modulation of the A549 cells exposed to ZnO NPs indicating alterations in the cytoskeleton.