The effect of TiO2 and Ag nanoparticles on reproduction and development of Drosophila melanogaster and CD-1 mice

Exposure to Titanium Dioxide Nanoparticles Leads to Specific Disorders of Spermatid Elongation via Multiple Metabolic Pathways in Drosophila Testes

Titanium dioxide nanoparticles (TiO2 NPs) have been extensively utilized in various applications. However, the regulatory mechanism behind the reproductive toxicity induced by TiO2 NP exposure remains largely elusive. In this study, we employed a Drosophila model to assess potential testicular injuries during spermatogenesis and conducted bulk RNA-Seq analysis to elucidate the underlying mechanisms. Our results reveal that while prolonged exposure to lower concentrations of TiO2 NPs (0.45 mg/mL) for 30 days did not manifest reproductive toxicity, exposure at concentrations of 0.9 and 1.8 mg/mL significantly impaired spermatid elongation in Drosophila testes. Notably, bulk RNA-seq analysis revealed that TiO2 NP exposure affected multiple metabolic pathways including carbohydrate metabolism and cytochrome P450. Importantly, the intervention of glutathione (GSH) significantly protected against reproductive toxicity induced by TiO2 NP exposure, as it restored the number of Orb-positive spermatid clusters in Drosophila testes. Our study provides novel insights into the specific detrimental effects of TiO2 NP exposure on spermatid elongation through multiple metabolic alterations in Drosophila testes and highlights the protective role of GSH in countering this toxicity.

Titanium Dioxide Nanoparticles Induce Maternal Preeclampsia-like Syndrome and Adverse Birth Outcomes via Disrupting Placental Function in SD Rats

The escalating utilization of titanium dioxide nanoparticles (TiO2 NPs) in everyday products has sparked concerns regarding their potential hazards to pregnant females and their offspring. To address these concerns and shed light on their undetermined adverse effects and mechanisms, we established a pregnant rat model to investigate the impacts of TiO2 NPs on both maternal and offspring health and to explore the underlying mechanisms of those impacts. Pregnant rats were orally administered TiO2 NPs at a dose of 5 mg/kg body weight per day from GD5 to GD18 during pregnancy. Maternal body weight, organ weight, and birth outcomes were monitored and recorded. Maternal pathological changes were examined by HE staining and TEM observation. Maternal blood pressure was assessed using a non-invasive blood analyzer, and the urinary protein level was determined using spot urine samples. Our findings revealed that TiO2 NPs triggered various pathological alterations in maternal liver, kidney, and spleen, and induced maternal preeclampsia-like syndrome, as well as leading to growth restriction in the offspring. Further examination unveiled that TiO2 NPs hindered trophoblastic cell invasion into the endometrium via the promotion of autophagy. Consistent hypertension and proteinuria resulted from the destroyed the kidney GBM. In total, an exposure to TiO2 NPs during pregnancy might increase the risk of human preeclampsia through increased maternal arterial pressure and urinary albumin levels, as well as causing fetal growth restriction in the offspring.

Developmental impacts and toxicological hallmarks of silver nanoparticles across diverse biological models

Silver nanoparticles (AgNPs), revered for their antimicrobial prowess, have become ubiquitous in a range of products, from biomedical equipment to food packaging. However, amidst their rising popularity, concerns loom over their possible detrimental effects on fetal development and subsequent adult life. This review delves into the developmental toxicity of AgNPs across diverse models, from aquatic species like zebrafish and catfish to mammalian rodents and in vitro embryonic stem cells. Our focus encompasses the fate of AgNPs in different contexts, elucidating associated hazardous results such as embryotoxicity and adverse pregnancy outcomes. Furthermore, we scrutinize the enduring adverse impacts on offspring, spanning impaired neurobehavior function, reproductive disorders, cardiopulmonary lesions, and hepatotoxicity. Key hallmarks of developmental harm are identified, encompassing redox imbalances, inflammatory cascades, DNA damage, and mitochondrial stress. Notably, we explore potential explanations, linking immunoregulatory dysfunction and disrupted epigenetic modifications to AgNPs-induced developmental failures. Despite substantial progress, our understanding of the developmental risks posed by AgNPs remains incomplete, underscoring the urgency of further research in this critical area.

Titanium-doped PET nanoplastics, from opaque milk bottle degradation, as a model of environmental true-to-life nanoplastics. Hazardous effects on Drosophila

Micro and nanoplastics (MNPLs) are emergent environmental pollutants, resulting from the degradation of plastic waste, requiring urgent information on their potential risks to human health. To determine such risks, reliable true-to-life materials are essential. In this work, we have used titanium-doped PET NPLs [PET(Ti)NPLs], obtained by grinding opaque milk polyethylene terephthalate (PET) bottles, as a true-to-life MNPLs model. These opaque PET bottles, with an average size of 112 nm, contain about 3% Ti in the form of titanium dioxide rod nanoparticles. TEM investigation confirmed the mixed Ti/PET nature of the obtained true-to-life NPLs, and the rod shape of the embedded TiO2NPs. In the in vivo Drosophila model neither PET(Ti)NPLs nor TiO2NPs reduced the survival rates, although their internalization was confirmed in different compartments of the larval body by using confocal and transmission electron microscopies. The presence of Ti in the PET(Ti)NPLs permitted to quantify its presence both in larvae (2.1 ± 2.2 μg/g of Ti) and in the resulting adults (3.4 ± 3.2 μg/g of Ti) after treatment with 500 μg/g food of PET(Ti)NPL, suggesting its potential use to track their fate in more complex organisms such as mammals. PET(Ti)NPLs, as well as TiO2NPs, altered the expression of genes driving different response pathways, inducing significant oxidative stress levels (up to 10 folds), and genotoxicity. This last result on the genotoxic effects is remarkable in the frame of the hot topic discussion on the risk that titanium compounds, used as food additives, may pose to humans.

Nanomedicine for Maternal and Fetal Health

Conception, pregnancy, and childbirth are complex processes that affect both mother and fetus. Thus, it is perhaps not surprising that in the United States alone, roughly 11% of women struggle with infertility and 16% of pregnancies involve some sort of complication. This presents a clear need to develop safe and effective treatment options, though the development of therapeutics for use in women's health and particularly in pregnancy is relatively limited. Physiological and biological changes during the menstrual cycle and pregnancy impact biodistribution, pharmacokinetics, and efficacy, further complicating the process of administration and delivery of therapeutics. In addition to the complex pharmacodynamics, there is also the challenge of overcoming physiological barriers that impact various routes of local and systemic administration, including the blood-follicle barrier and the placenta. Nanomedicine presents a unique opportunity to target and sustain drug delivery to the reproductive tract and other relevant organs in the mother and fetus, as well as improve the safety profile and minimize side effects. Nanomedicine-based approaches have the potential to improve the management and treatment of infertility, obstetric complications, and fetal conditions.

The food additive titanium dioxide hinders intestinal production of TGF-β and IL-10 in mice, and long-term exposure in adults or from perinatal life blocks oral tolerance to ovalbumin

Food hypersensitivities are increasing in industrialized countries, and foodborne nanoparticles (NPs) are suspected as co-factors in their aetiology. Food-grade titanium dioxide (fg-TiO2), a food colouring agent, is composed of NPs with immunomodulatory properties. We investigated whether fg-TiO2 may compromise the establishment of oral tolerance (OT) to food proteins using a model of OT induction to ovalbumin (OVA) in mice, and whether a perinatal exposure could trigger this effect. In pregnant mice fed a TiO2-enriched diet, ICP-MS and TEM-EDX analyses showed passage of TiO2 NPs into the foetus. When their weaned offspring were fed the same diet, a breakdown in OT to OVA was observed at adulthood, characterized by a high anti-OVA IgG production compared to controls. However, adult mice directly exposed to fg-TiO2 did not induce OT to OVA either, ruling out a developmental origin for these effects. When these mice were orally challenged with OVA, intestinal inflammation demonstrated hypersensitivity to OVA. In OVA-naïve mice, fg-TiO2 exposure impaired intestinal TGF-β and IL-10 production, of key role in OT induction and maintenance. These findings showed that long-term exposure to TiO2 as food additive alters anti-inflammatory cytokine profile, and leads to OT failure regardless of the timing of TiO2 exposure throughout life.

TiO2 nanoparticles' library toxicity (UV and non-UV exposure) - High-throughput in vivo transcriptomics reveals mechanisms

The hazards of nanomaterials/nanoparticles (NMs/NPs) are mostly assessed using individual NMs, and a more systematic approach, using many NMs, is needed to evaluate its risks in the environment. Libraries of NMs, with a range of identified different but related characters/descriptors allow the comparison of effects across many NMs. The effects of a custom designed Fe-doped TiO₂ NMs library containing 11 NMs was assessed on the soil model Enchytraeus crypticus (Oligochaeta), both with and without UV (standard fluorescent) radiation. Effects were analyzed at organism (phenotypic, survival and reproduction) and gene expression level (transcriptomics, high-throughput 4x44K microarray) to understand the underlying mechanisms. A total of 48 microarrays (20 test conditions) were done plus controls (UV and non-UV). Unique mechanisms induced by TiO₂ NPs exposure included the impairment in RNA processing for TiO₂_10nm, or deregulated apoptosis for 2%FeTiO₂_10nm. Strikingly apparent was the size dependent effects such as induction of reproductive effects via smaller TiO₂ NPs (≤12 nm) - embryo interaction, while larger particles (27 nm) caused reproductive effects through different mechanisms. Also, phagocytosis was affected by 12 and 27 nm NPs, but not by ≤11 nm. The organism level study shows the integrated response, i.e. the result after a cascade of events. While uni-cell models offer key mechanistic information, we here deliver a combined biological system level (phenotype and genotype), seldom available, especially for environmental models.

Hydroxyapatite-binding Silver/Titanium Dioxide as a Potential Control Compound Against Mosquito Vectors, Aedes aegypti (Diptera: Culicidae) and Anopheles dirus (Diptera: Culicidae)

Controlling mosquitoes is vital for counteracting the rising number of mosquito-borne illnesses. Vector control requires the implementation of various measures; however, current methods lack complete effectiveness, and new control agents or substances are urgently needed. Therefore, this study developed a nonwoven fabric sheet coated with hydroxyapatite-binding silver/titanium dioxide compound (hydroxyapatite-binding silver/titanium dioxide sheet [HATS])and evaluated its effectiveness on all stages of laboratory Aedes aegypti (Linnaeus); Diptera: Culicidae and Anopheles dirus (Peyton & Harrison); Diptera: Culicidae. We reared larvae with HATS and control sheets and assessed their mortality, emergence, and hatching rates. The submersion rates of engorged female mosquitoes in submerged HATS and control sheets were also compared. The HATS strongly affected mosquito development, resulting in high mortality rates (mean ± SE) of 99.66 ± 0.58% (L1-L2) and 91.11 ± 9.20% (L3-L4) for Ae. aegypti and 100% of both stages for An. dirus. In contrast, mosquitoes raised in the control sheet showed relatively high survival rates of 92.33 ± 3.21% (L1-L2) and 95.67 ± 0.58% (L3-L4) for Ae. aegypti and 86.07 ± 3.53% (L1-L2) and 92.01 ± 8.67% (L3-L4) for An. dirus. Submersion of engorged females was found in the HATS oviposition cup, leading to a decreased number of eggs and a low hatching rate compared to that of the control. Overall, HATS may be a useful new control method for Ae. aegypti and An. dirus.

Adverse Outcome Pathways Associated with the Ingestion of Titanium Dioxide Nanoparticles-A Systematic Review

Titanium dioxide nanoparticles (TiO₂-NPs) are widely used, and humans are exposed through food (E171), cosmetics (e.g., toothpaste), and pharmaceuticals. The oral and gastrointestinal (GIT) tract are the first contact sites, but it may be systemically distributed. However, a robust adverse outcome pathway (AOP) has not been developed upon GIT exposure to TiO₂-NPs. The aim of this review was to provide an integrative analysis of the published data on cellular and molecular mechanisms triggered after the ingestion of TiO₂-NPs, proposing plausible AOPs that may drive policy decisions. A systematic review according to Prisma Methodology was performed in three databases of peer-reviewed literature: Pubmed, Scopus, and Web of Science. A total of 787 records were identified, screened in title/abstract, being 185 used for data extraction. The main endpoints identified were oxidative stress, cytotoxicity/apoptosis/cell death, inflammation, cellular and systemic uptake, genotoxicity, and carcinogenicity. From the results, AOPs were proposed where colorectal cancer, liver injury, reproductive toxicity, cardiac and kidney damage, as well as hematological effects stand out as possible adverse outcomes. The recent transgenerational studies also point to concerns with regard to population effects. Overall, the findings further support a limitation of the use of TiO₂-NPs in food, announced by the European Food Safety Authority (EFSA).

An Overview of Essential Microelements and Common Metallic Nanoparticles and Their Effects on Male Fertility

Numerous factors affect reproduction, including stress, diet, obesity, the use of stimulants, or exposure to toxins, along with heavy elements (lead, silver, cadmium, uranium, vanadium, mercury, arsenic). Metals, like other xenotoxins, can cause infertility through, e.g., impairment of endocrine function and gametogenesis or excess production of reactive oxygen species (ROS). The advancement of nanotechnology has created another hazard to human safety through exposure to metals in the form of nanomaterials (NMs). Nanoparticles (NPs) exhibit a specific ability to penetrate cell membranes and biological barriers in the human body. These ultra-fine particles (<100 nm) can enter the human body through the respiratory tract, food, skin, injection, or implantation. Once absorbed, NPs are transported to various organs through the blood or lymph. Absorbed NPs, thanks to ultrahigh reactivity compared to bulk materials in microscale size, disrupt the homeostasis of the body as a result of interaction with biological molecules such as DNA, lipids, and proteins; interfering with the functioning of cells, organs, and physiological systems; and leading to severe pathological dysfunctions. Over the past decades, much research has been performed on the reproductive effects of essential trace elements. The research hypothesis that disturbances in the metabolism of trace elements are one of the many causes of infertility has been unquestionably confirmed. This review examines the complex reproductive risks for men regarding the exposure to potentially harmless xenobiotics based on a series of 298 articles over the past 30 years. The research was conducted using PubMed, Web of Science, and Scopus databases searching for papers devoted to in vivo and in vitro studies related to the influence of essential elements (iron, selenium, manganese, cobalt, zinc, copper, and molybdenum) and widely used metallic NPs on male reproduction potential.

Gestational exposure to silver nanoparticles enhances immune adaptation and protection against streptozotocin-induced diabetic nephropathy in mice offspring

Silver nanoparticles (AgNPs) possess unique antimicrobial properties. As a result, they are being increasingly used in a wide range of applications. Several studies have shown detrimental effects of AgNPs exposure, including inflammation, accumulation, and cellular damage to different organs. However, the effect of AgNPs exposure during gestation, a critical and susceptible period of human development, on pregnant females and its long-term effects on offspring's health has not been studied. Therefore, we conducted a long-term study where we assessed the effect of gestational AgNPs exposure on pregnant mice and followed their offspring until the age of 12 months. Gestational exposure to AgNPs induced systemic inflammation in the pregnant mice at gestational day (GD) 18. Interestingly, developing fetuses exposed to AgNPs, showed anti-inflammatory conditions as indicated by reduced expression of inflammatory genes in fetal organs at GD 18 and reduced serum levels of TNF-α, IFN-γ, IL-17A, IL-6, and MCP-1 in AgNPs exposed pups at postnatal day (PD) 2. Surprisingly, post-weaning, AgNPs exposed offspring showed a heightened immune activation as shown by upregulation of inflammatory cytokines at PD 28, which persisted till late in life. Moreover, we observed metabolic alterations which persisted until adulthood in mice. To understand the impact of long-term immunometabolic changes on the progression of diabetes and kidney diseases under stressed conditions, we exposed offspring to streptozotocin which revealed a protective role of low-dose gestational AgNPs exposure against streptozotocin-induced diabetes and associated nephropathy.

Advanced human developmental toxicity and teratogenicity assessment using human organoid models

Tremendous progress has been made in the field of toxicology leading to the advance of developmental toxicity assessment. Conventional animal models and in vitro two-dimensional models cannot accurately describe toxic effects and predict actual in vivo responses due to obvious inter-species differences between humans and animals, as well as the lack of a physiologically relevant tissue microenvironment. Human embryonic stem cell (hESC)- and induced pluripotent stem cell (iPSC)-derived three-dimensional organoids are ideal complex and multicellular organotypic models, which are indispensable in recapitulating morphogenesis, cellular interactions, and molecular processes of early human organ development. Recently, human organoids have been used for drug discovery, chemical toxicity and safety in vitro assessment. This review discusses the recent advances in the use of human organoid models, (i.e., brain, retinal, cardiac, liver, kidney, lung, and intestinal organoid models) for developmental toxicity and teratogenicity assessment of distinct tissues/organs following exposure to pharmaceutical compounds, heavy metals, persistent organic pollutants, nanomaterials, and ambient air pollutants. Combining next-generation organoid models with innovative engineering technologies generates novel and powerful tools for developmental toxicity and teratogenicity assessment, and the rapid progress in this field is expected to continue.

Damaging effects of TiO2 nanoparticles on the ovarian cells of Bombyx mori

As a new type of biologically compatible material, TiO₂ NPs are widely used in the industry as additives, drug carriers, and components of skin care products. Due to their wide use, residual TiO₂ NPs in the environment are a safety concern that has attracted extensive attention. In this study, the ovarian cell line BmN of the model organism Bombyx mori was used to reveal the damaging effects of TiO₂ NPs exposure. The results demonstrated that TiO₂ NPs exhibited a dose-dependent effect on the relative cell viability, with significant toxic effects being observed above 20 mg/L. Oxidative damage analysis showed that ROS accumulated significantly in BmN cells after exposure to TiO₂ NPs (P ≤ 0.05) and induced DNA damage. Further analysis revealed that the transcriptional levels of key superoxide dismutase genes (SOD) decreased significantly, while the transcriptions of key genes of the MAPK/NF-κB signaling pathway (P38, MEK, ERK and REL) and the downstream inflammatory factor genes (IL6 and TNFSF5) were all significantly up-regulated (P ≤ 0.05). Overall, our results indicate that exposure to TiO₂ NPs leads to reduced transcription of antioxidant genes, accumulation of peroxides, and inflammation. These findings provide valuable data for the safety evaluation of environmental residues of TiO₂ NPs.

Attributes of oxidative stress in the reproductive toxicity of nickel oxide nanoparticles in male rats

The nanoparticles of nickel are now being widely used in industrial, commercial, and biomedical applications. In recent years, health safety issues posed by them have aroused concerns among health scientists. The aim of the present study was to investigate the role of oxidative stress in male reproductive toxicity induced by nickel oxide nanoparticles in rats. Male Wistar rats (140-170 g) were administered with nickel oxide nanoparticles (NiONPs) (particles size <30 nm) (5 mg/kg body weight) by gavage for 30 days. Its effects on different parameters, viz., sperm count, motility, and morphology, were investigated. DNA damage in sperms was monitored through comet assay. All these observations indicated a spermicidal effect of NiONPs. Results on lipid peroxidation (MDA, H₂O₂, and NO) and oxidative stress (GSH, GPx, and catalase) thus studied in testes exhibited adverse effects of NiONPs. Histopathological results on male reproductive organs, viz., testis, epididymis, vas deferens, seminal vesicles, and prostate also demonstrated moderate to severe toxicity. A comparison of these results with those obtained on nickel oxide microparticle (NiOMP)-treated rats showed that NiONPs are more toxic than NiOMPs. Furthermore, NiONPs could create an imbalance between oxidants and antioxidants in the testes. It is concluded that redox imbalance in testes constitutes a major mechanism of NiONP-induced reproductive toxicity.

Elimination of oxidative stress and genotoxicity of biosynthesized titanium dioxide nanoparticles in rats via supplementation with whey protein-coated thyme essential oil

The green synthesis of metal nanoparticles is growing dramatically; however, the toxicity of these biosynthesized particles against living organisms is not fully explored. Therefore, this study was designed to synthesize and characterize TiO₂-NPs, encapsulation and characterization thyme essential oil (ETEO), and determination of the bioactive constituents of ETEO using GC-MS and evaluate their protective role against TiO₂-NPs-induced oxidative damage and genotoxicity in rats. Six groups of rats were treated orally for 30 days including the control group, TiO₂-NPs (300 mg/kg b.w)-treated group, ETEO at low (50 mg/kg b.w) or high dose (100 mg/kg b.w)-treated groups, and TiO₂-NPs plus ETEO at the two doses-treated groups. Blood and tissues were collected for different assays. The GC-MS results indicated the presence of 21 compounds belonging to phenols, terpene derivatives, and heterocyclic compounds. The synthesized TiO₂-NPs were 45 nm tetragonal particles with a zeta potential of -27.34 mV; however, ETEO were 119 nm round particles with a zeta potential of -28.33 mV. TiO₂-NPs administration disturbs the liver and kidney markers, lipid profile, cytokines, oxidative stress parameters, the apoptotic and antioxidant hepatic mRNA expression, and induced histological alterations in the liver and kidney tissues. ETEO could improve all these parameters in a dose-dependent manner. It could be concluded that ETEO is a promising candidate for the protection against TiO₂-NPs and can be applied safely in food applications.

Developmental exposure to silver nanoparticles leads to long term gut dysbiosis and neurobehavioral alterations

Due to their antimicrobial properties, silver nanoparticles (AgNPs) are used in a wide range of consumer products that includes topical wound dressings, coatings for biomedical devices, and food-packaging to extend the shelf-life. Despite their beneficial antimicrobial effects, developmental exposure to such AgNPs may lead to gut dysbiosis and long-term health consequences in exposed offspring. AgNPs can cross the placenta and blood–brain-barrier to translocate in the brain of offspring. The underlying hypothesis tested in the current study was that developmental exposure of male and female mice to AgNPs disrupts the microbiome–gut–brain axis. To examine for such effects, C57BL6 female mice were exposed orally to AgNPs at a dose of 3 mg/kg BW or vehicle control 2 weeks prior to breeding and throughout gestation. Male and female offspring were tested in various mazes that measure different behavioral domains, and the gut microbial profiles were surveyed from 30 through 120 days of age. Our study results suggest that developmental exposure results in increased likelihood of engaging in repetitive behaviors and reductions in resident microglial cells. Echo-MRI results indicate increased body fat in offspring exposed to AgNPs exhibit. Coprobacillus spp., Mucispirillum spp., and Bifidobacterium spp. were reduced, while Prevotella spp., Bacillus spp., Planococcaceae, Staphylococcus spp., Enterococcus spp., and Ruminococcus spp. were increased in those developmentally exposed to NPs. These bacterial changes were linked to behavioral and metabolic alterations. In conclusion, developmental exposure of AgNPs results in long term gut dysbiosis, body fat increase and neurobehavioral alterations in offspring.

Fetotoxicity of Nanoparticles: Causes and Mechanisms

The application of nanoparticles in consumer products and nanomedicines has increased dramatically in the last decade. Concerns for the nano-safety of susceptible populations are growing. Due to the small size, nanoparticles have the potential to cross the placental barrier and cause toxicity in the fetus. This review aims to identify factors associated with nanoparticle-induced fetotoxicity and the mechanisms involved, providing a better understanding of nanotoxicity at the maternal–fetal interface. The contribution of the physicochemical properties of nanoparticles (NPs), maternal physiological, and pathological conditions to the fetotoxicity is highlighted. The underlying molecular mechanisms, including oxidative stress, DNA damage, apoptosis, and autophagy are summarized. Finally, perspectives and challenges related to nanoparticle-induced fetotoxicity are also discussed.

Nanoparticles induced embryo-fetal toxicity

Applications of nanomaterials cause a general concern on their toxicity when they intentionally (such as in medicine) or unintentionally (environment exposure) enter into the human body. As a special subpopulation, pregnant women are more susceptible to nanoparticle (NP)-induced toxicity. More importantly, prenatal exposures may affect the entire life of the fetus. Through blood circulation, NPs may cross placental barriers and enter into fetus. A cascade of events, such as damage in placental barriers, generation of oxidative stress, inflammation, and altered gene expression, may induce delayed or abnormal fetal development. The physicochemical properties of NPs, exposure time, and other factors directly affect nanotoxicity in pregnant populations. Even though results from animal studies cannot directly extrapolate to humans, compelling evidence has already shown that, for pregnant women, caution must be taken when dealing with nanomedicines or NP pollutants.

Developmental Toxicity of the Neural Tube Induced by Titanium Dioxide Nanoparticles in Mouse Embryos

Background:

This study investigated the potential effects of Titanium dioxide nanoparticles (Tio2NPs) followed by maternal gavage on fetal development and neural tube formation during pregnancy in mice.

Methods:

Thirty pregnant mice were randomly divided into five main study groups including the untreated control and 4 experimental groups (n=6 per group). The control group was treated with normal saline and the experimental groups were orally treated with doses of 30, 150, 300, and 500 mg/kg Body Weight (BW) of Tio2NPs during pregnancy. On gestational day 16 and 19 (n=3 per group), pregnant mice were euthanized and then examined for neural tube defects and compared with control. Serial transverse sections were prepared in both cranial region and in lumbar region of spinal cord.

Results:

Treatment with Tio2NPs resulted in low fetal weight and short length, dilation of lateral ventricle, thinning of cerebral cortex and spinal cord, spina bifida occulta and an increase in the number of apoptotic neurons in exposed embryos at doses of 300 and 500 mg/kg (p<0.05).

Conclusion:

It seems that exposure to nanoparticles of Tio2 during pregnancy induces growth retardation and for the first time, teratogenicity of this nanomaterial in neural tube development and induction of defects such as spinal bifida, reduction in cortical thickness and dilatation of lateral ventricles were verified which can be related to incidence of apoptosis in central nervous system.

Administration of silver nanoparticles affects ovarian steroidogenesis and may influence thyroid hormone metabolism in hens (Gallus domesticus)

This study aimed to determine the in vivo effect of silver nanoparticles (AgNPs) on the concentration of sex steroids (progesterone - P4, estradiol - E2, testosterone - T) and thyroid hormones (thyroxine - T₄, triiodothyronine - T₃) in the blood plasma as well as the messenger ribonucleic acid (mRNA) and protein expression of HSD3β, CYP17A1 and CYP19A1 enzymes and steroid hormone concentrations in chicken ovarian follicles. AgNPs did not affect serum steroid hormone levels, but increased T₃ levels depending on the size and concentration of AgNPs. At the level of ovarian tissues, AgNPs: (i) affected the levels of E2 and T in prehierachical follicles; (ii) reduced the expression of CYP19A1 mRNA and protein and consequently diminished E2 concentration in small white follicles; and (iii) increased the expression of CYP17A1 mRNA in large white follicles, without changing its protein expression. The results indicate that AgNPs affect chicken ovarian steroidogenesis. The effects of AgNPs depend on exposure time, the type of follicle and the degree of its development and are associated with the modulation of steroidogenic gene expression and E2 and T synthesis. Prehierachical follicles seem to be more susceptible to AgNPs than preovulatory ones. In conclusion, AgNPs by targeting the chicken ovary may indirectly influence the selection processes of prehierarchical follicles to the pre-ovulatory hierarchy and disturb the ovarian steroidogenesis. Furthermore, AgNPs may affect thyroid hormone metabolism in different ways by size which in turn may influence energy homeostasis of the target cells.

Breakthrough of ZrO2 nanoparticles into fetal brains depends on developmental stage of maternal placental barrier and fetal blood-brain-barrier

Ingestion of nanoparticles may cause various damages to human body. However, how such ingestion by pregnant mother influences fetal development is not known because, presumably, ingested nanoparticles have to cross multiple biological barriers (such as intestinal and placental) to reach fetus. To answer this crucial question, here we investigated how a relatively biocompatible zirconia nanoparticles (ZrO₂ NPs, 16 nm) were translocated to fetal brains in three exposure models of pregnant mice: Model 1, oral exposure of nanoparticles before maternal blood-placental barrier (BPB) was fully developed; Model 2, exposures after BPB was developed, but before fetal blood-brain-barrier (BBB) was fully developed; Model 3, exposures after both maternal BPB and fetal BBB were fully developed. Our experimental results showed that translocation of ZrO₂ NPs into fetal brains was 55 % higher in Model 2 and 96 % higher in Model 1 compared with that in Model 3 after nanoparticles (50 mg/kg) were orally exposed to pregnant mice. Therefore, nanoparticles are able to cross multiple biological barriers and nanotoxicity to fetus is highly dependent on stages of pregnancy and fetal development or the maturity of multiple biological barriers. Oral exposures to nanoparticles during pregnancy are dangerous to fetal brain development, especially in early pregnancy.

In Vivo and In Vitro Evaluation of Bull Semen Processed with Zinc (Zn) Nanoparticles

Defective sperms cause fertilization failure under both in vivo and in vitro conditions. Therefore, providing optimal conditions during semen storage is a prerequisite for maintaining viability. The current study investigated bull semen quality in vitro and in vivo when zinc (Zn) nanoparticles were used as antioxidant during semen processing and cryopreservation. In total, 32 ejaculates were collected from four Holstein bulls. All ejaculates were pooled and diluted with Bioxcell-extender containing 0 (control group), 10^-6, 10^-5, 10^-4, 10^-3, and 10^-2 M of Zn nanoparticles. Several physical and biochemical sperm parameters were determined after freeze-thawing process. In vitro embryo development rate and pregnancy rate were monitored after in vitro fertilization or artificial insemination using semen treated with Zn nanoparticles. Plasma membrane integrity was improved (P < 0.05) in bull semen treated with 10^-6 M (69.3%), and 10^-2 (62.4%) of Zn nanoparticles compared to untreated group (51.3%). In addition, proportions of live spermatozoa with active mitochondria were increased (P < 0.05) in semen supplemented with Zn nanoparticles at concentration of 10^-6 M (67.3%), and 10^-2 (85.3%) compared to control group (49.8%). Moreover, the level of MDA was lower (P < 0.05) in semen with Zn nanoparticles at 10^-6 M (2.97 mol/mL) and 10^-2 (2.7 mol/mL) concentrations than control semen samples (3.77 mol/mL). However, sperm total and progressive motility, sperm viability, DNA fragmentation, and pregnancy rate were not affected by treatment of semen with Zn nanoparticles. On the other hand, supplementation of in vitro maturation media with 10^-6 M Zn nanoparticles has increased blastocyst rate (P < 0.05) compared to other experimental groups, while addition of Zn nanoparticles-treated sperm during in vitro fertilization did not affect embryo development rate. In conclusion, supplementation of Zn nanoparticles to semen has improved its quality without affecting embryo development rate in vitro. However, in vitro embryo development rate was increased when Zn nanoparticles were supplemented to IVM media. This support the notion of Zn nanoparticles beneficial action on improving bovine gametes quality without affecting pregnancy rate.

Effects of silver nanoparticles prenatal exposure on rat offspring development

Many types of nanocomposites employed in food packaging are based on silver nanoparticles (AgNP) because of their antibacterial properties, which can increase food shelf-life. As the commercialization of AgNP products has been expanding, the released of such nanoparticles in the environment has caused enormous concern, once they can pose potential risks to the environment and human beings. For instance, exposure of the maternal environment to nanomaterials during pregnancy may impact the health of the dam, fetus and offspring. In this context, here we investigated the effects of prenatal exposure of AgNP on the pregnancy outcomes of dams and postnatal development of their offspring. Pregnant Wistar rats were exposed to distinct AgNP concentrations (0, 1, 3 and 5 μg/kg/day) from beginning to the end of pregnancy. At parturition, newborns were observed regarding clinical signs of toxicity and survival rate. The offspring was examined by evaluating developmental endpoints. A delay in time for vaginal opening and testes descent were detected in the offspring exposed to AgNP during embryonic development. Our results indicate that prenatal exposure to AgNP can compromise neonatal rats' postnatal development, especially the reproductive features.

Changes in the wing shape and size in Drosophila melanogaster treated with food grade titanium dioxide nanoparticles (E171) - A multigenerational study

Drosophila is among the most commonly used models for toxicity assessment of different types of nanoparticles. This study aims to examine the effects of a constant exposure to the low concentration of human food grade titanium dioxide nanoparticles (TiO₂ E171) on Drosophila melanogaster wing morphology over multiple generations. Subsequently, the Geometric Morphometrics Analysis was employed to examine possible changes in the wing shape and size of the treated flies. The treatment resulted in the diminishment but not a disruption in the sexual dimorphism in wings. Consequently, the female flies were clearly separated from the male flies by the differences in wing morphology as in the control group. A splitting by generations was overly similar within the control and the treatment, but it was slightly more pronounced in the treatment. However, the observed generational differences seemed mostly random between generations, irrespective of the treatment. Specifically, the treated groups displayed slightly higher splitting by generations in females than in males. Regardless of the generation, the results show a clear splitting by the differences in the wing shape between the treated flies and the flies from control. The mean value of centroid size, which refers to the wing size, of both female and male wings was smaller in the treatment when compared to the control. The overall effect of TiO₂ was to induce significant difference in Drosophila wing morphology but it did not alter the general wing morphology pattern. Therefore, the change in the wings occurred only within the normally allowed wing variation.

Recent insights on indirect mechanisms in developmental toxicity of nanomaterials

BACKGROUND

Epidemiological and animal studies provide compelling indications that environmental and engineered nanomaterials (NMs) pose a risk for pregnancy, fetal development and offspring health later in life. Understanding the origin and mechanisms underlying NM-induced developmental toxicity will be a cornerstone in the protection of sensitive populations and the design of safe and sustainable nanotechnology applications.

MAIN BODY

Direct toxicity originating from NMs crossing the placental barrier is frequently assumed to be the key pathway in developmental toxicity. However, placental transfer of particles is often highly limited, and evidence is growing that NMs can also indirectly interfere with fetal development. Here, we outline current knowledge on potential indirect mechanisms in developmental toxicity of NMs.

SHORT CONCLUSION

Until now, research on developmental toxicity has mainly focused on the biodistribution and placental translocation of NMs to the fetus to delineate underlying processes. Systematic research addressing NM impact on maternal and placental tissues as potential contributors to mechanistic pathways in developmental toxicity is only slowly gathering momentum. So far, maternal and placental oxidative stress and inflammation, activation of placental toll-like receptors (TLRs), impairment of placental growth and secretion of placental hormones, and vascular factors have been suggested to mediate indirect developmental toxicity of NMs. Therefore, NM effects on maternal and placental tissue function ought to be comprehensively evaluated in addition to placental transfer in the design of future studies of developmental toxicity and risk assessment of NM exposure during pregnancy.

Silver nanoparticles (AgNPs) and AgNO3 perturb the specification of human hepatocyte-like cells and cardiomyocytes

Silver nanoparticles (AgNPs) are commonly utilized industrial compounds mostly because of their antimicrobial properties. Nevertheless, our understanding of their potential developmental toxicity in humans is still limited. Embryonic stem cells (ESCs) are powerful in vitro tools for developmental toxicity assessments of chemicals. Here, we evaluated the potential developmental toxicity during early embryogenesis of AgNPs and AgNO₃ with human ESC (hESC)-based differentiation systems in vitro. We found that human relevant concentrations of AgNPs and Ag ions affected the specification of two of the three primary germ layers, endoderm and mesoderm, without drastically affecting ectoderm. Furthermore, the two forms of Ag impaired the generation and functions of hepatocytes-like cells derived from endoderm, by decreasing the expression of important liver markers such as AFP, ALB, and HNF4A, and altering glycogen storage. When considering cardiac development, AgNPs and AgNO₃ manifested opposite adverse effects, in that AgNPs increased while AgNO₃ decreased the expression of typical cardiac markers (NKX2.5, MYH6, and ISL) in hESC-derived cardiomyocytes. In conclusion, our findings argue for a potential developmental toxicity of AgNP doses we are exposed to, or levels detected in the human body, especially at very early stages during embryogenesis, and which may not be just due to Ag leakage. Moreover, mesendoderm-derived cell types, tissues and organs may be more prone to AgNP toxicity than ectoderm lineages.

Hazard characterization of silver nanoparticles for human exposure routes

Silver nanoparticles (AgNPs) have been widely used for a multitude of applications without full comprehensive knowledge regarding their safety. In particular, lack of data on hazard characterization may lead to uncertainties regarding potential human health risk. To provide the foundation for human health risk assessment of AgNPs, this study evaluates existing hazard characterization data, including reported pharmacokinetics, symptoms, and their corresponding dose-response relationships. Human equivalent relationships are also provided by extrapolation from animal dose-response relationships. From the data analyzed, it appears that AgNPs may persist for long periods (from days to years) in the human body. It was found that AgNP toxicity on traditional major targets of exogenous substances were generally underestimated. Some omissions of toxicity on sensitive systems in the AgNP toxicity assessment require attention, such as reprotoxicity and neurotoxicity. The necessity of the establishment of toxicity tests specifically for nanomaterials is highlighted. The scientific basis of a toxicity testing strategy is advised by this study, which paves the way for the monitoring and regulation of the ENP utilization in various industries.

The use of ex vivo ovary culture for assessment of alterations in steroidogenesis following neonatal exposure to poly(ethylene glycol)-block-polylactide methyl ether or titanium dioxide nanoparticles in Wistar rats

Objectives. Rapid development and widespread application of different types of nanoparticles (NPs) may result in increased exposure of humans and animals to NPs. Recently, reproductive toxicity due to NP exposure has become a major component of risk assessment. Current data have suggested that NPs may pose adverse effects on male and female reproductive health by altering normal testis and ovarian structure, and sex hormone levels. To detect possible alterations in steroidogenesis in adult and infantile rats following neonatal exposure to polymeric poly(ethylene glycol)-block-polylactide methyl ether (PEG-b-PLA) or titanium dioxide (TiO2) NPs, whole ovary cultures were used.

Methods. Newborn female Wistar rats were intraperitoneally (i.p.) injected daily with two different doses of PEG-b-PLA NPs (20 and 40 mg/kg body weight, b.w.) or TiO2 NPs (1% LD50 TiO2=59.2 µg/kg b.w. and 10% LD50 TiO2=592 µg/kg b.w.) from postnatal day 4 (PND 4) to PND 7. The ovaries were collected on PND73 and PND15 of PEG-b-PLA- and TiO2 NP-treated rats, respectively, and their corresponding control animals. Minced ovaries were cultured in vitro in the absence (basal conditions) or presence of gonadotropins (follicle-stimulating hormone, FSH and luteinizing hormone, LH) and insulin-like growth factor-1 (IGF-1) (stimulated conditions) for 6 days. At indicated time intervals, culture media were collected for steroid hormone (progesterone, estradiol) analysis by specific radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) kits.

Results. Basal progesterone and estradiol secretion by ovaries from adult rats (PND73) were significantly decreased (p<0.01) in both PEG-b-PLA-treated groups after 3 days and 1 day of ex vivo ovary culture, respectively, compared with control group. With the presence of FSH/LH and IGF-1 in the culture medium, progesterone and estradiol production significantly increased (p<0.001) compared to basal levels. Stimulated progesterone production was significantly decreased (p<0.05) in PEG-b-PLA40-treated group after 3 days of culture compared with controls. After ex vivo culture of rat ovaries collected on PND15, basal progesterone and estradiol levels measured in the culture media did not differ between control and both TiO2 NP-treated groups. The ovaries from rats neonatally exposed to both doses of TiO2 NPs failed to respond to FSH/IGF stimulation in progesterone secretion at all time intervals.

Conclusions. The obtained results indicate that neonatal exposure to NPs in female rats may alter ovarian steroidogenic output (steroid hormone secretion) and thereby might subsequently induce perturbation of mammalian reproductive functions. Possible mechanisms (induction of oxidative stress, inflammation) of adverse effects of NPs on ovarian function should be further elucidated.

Biological interactions between nanomaterials and placental development and function following oral exposure

We summarize the literature involving the deposition of nanomaterials within the placenta following oral exposure and the biological interactions between nanomaterials and placental development and function. The review focuses on the oral exposure of metal and metal oxide engineered nanomaterials (ENMs), carbon-based ENMs, and nanoplastics in animal models, with a minor discussion of intravenous injections. Although the literature suggests that the placenta is an efficient barrier in preventing nanomaterials from reaching the fetus, nanomaterials that accumulate in the placenta may interfere with its development and function. Furthermore, some studies have demonstrated a decrease in placental weight and association with adverse fetal health outcomes following oral exposure to nanomaterials. Since nanomaterials are increasingly used in food, food packaging, and have been discovered in drinking water, the risk for adverse impacts on placental development and functions, with secondary effects on embryo-fetal development, following unintentional maternal ingestion of nanomaterials requires further investigation.

Investigating the accumulation and translocation of titanium dioxide nanoparticles with different surface modifications in static and dynamic human placental transfer models

Titanium dioxide nanoparticles (TiO₂ NPs) are widely incorporated in various consumer products such as cosmetics and food. Despite known human exposure, the potential risks of TiO₂ NPs during pregnancy are not fully understood, but several studies in mice elucidated toxic effects on fetal development. It has also been shown that modifying NPs with positive or negative surface charge alters cellular uptake and abolishes fetotoxicity of silicon dioxide (SiO₂) NPs in mice. Here, we investigated accumulation and translocation of positively charged TiO₂-NH₂ and negatively charged TiO₂-COOH NPs at the placental barrier, to clarify whether surface charge provides a means to control TiO₂ NP distribution at the placental barrier. To ensure outcome relevant for humans, the recently developed in vitro human placental co-culture model and the gold standard amongst placental translocation models - the ex vivo perfusion of human term placental tissue - were employed during this study. Sector field-ICP-MS analysis of maternal and fetal supernatants as well as placental cells/tissues revealed a substantial accumulation of both TiO₂ NP types while no considerable placental translocation was apparent in both models. Characterization of agglomeration behavior demonstrated a strong and fast agglomeration of TiO₂-NH₂ and TiO₂-COOH NPs in the different culture media. Overall, our results indicate that surface charge is not a key factor to steer placental uptake and transfer of TiO₂. Moreover, the negligible placental transfer but high accumulation of TiO₂ NPs in placental tissue suggests that potential effects on fetal health may occur indirectly, which calls for further studies elucidating the impact of TiO₂ NPs on placental tissue functionality and signaling.

Silver nanoparticle-induced developmental inhibition of Drosophila melanogaster accompanies disruption of genetic material of larval neural stem cells and non-neuronal cells

A few studies had determined the effects of silver nanoparticles on the development of Drosophila melanogaster. However, none had addressed its genotoxic effects on specific larval cells of the fly in details. This study was conducted to determine the effects of silver nanoparticle on the development of D. melanogaster with simultaneous evaluation of its genotoxic potential on specific larval cell types that play important roles in immunological defenses as well as growth and development. Five male and five female flies were maintained in standard Drosophila melanogaster culture medium containing varying concentrations of silver nanoparticles, i.e., 25, 50, 100, 200, and 300 mg/l with control culture medium containing no nanoparticle. Total time needed for stage-specific development, population yield, and genotoxic effects on third instar larval polytene chromosomes, hemocytes, and neuroblasts was determined. Body pigmentation of pupae and young adults was examined visually. In comparison with control, silver nanoparticles dose dependently inhibited the metamororphosis and population yields of pupae and young adults of Drosophila melanogaster. Every concentration of the nanoparticles inhibited pupa to adult conversion, with huge reduction under the influence of nanoparticle concentration of 100 mg/ml and above. Developmental inhibition was accompanied by dose-dependent and significant structural aberrations of larval polytene chromosomes and deformities of hemocytes and neuroblasts. Pupae and young adults also exhibited gradual discoloration of body with the increase in exposure to nanoparticle concentration.

Evaluation of the effects of titanium dioxide and aluminum oxide nanoparticles through tarsal contact exposure in the model insect Oncopeltus fasciatus

Despite the increasing presence of metal nanoparticles in the biosphere as a consequence of their widespread use, knowledge about the impact of these nanoparticles on fauna, ecosystems and human health is far from completion. This is especially true for terrestrial invertebrates. Insects are environmentally exposed to nanoparticles by several ways, the ectopic contact being one of the most probable. The model insect Oncopeltus fasciatus, has been used in the present work for testing toxicity of nanoparticles present in a surface. Adverse effects of TiO₂ nanoparticles and Al₂O₃ in nanoparticulated or bulk form on mortality, reproductive and embryonic developmental parameters have been analyzed after tarsal contact of adult individuals of O. fasciatus. Effects were monitored in the unexposed filial generation from control and exposed adults. In order to know the effect of the nanoparticles on the insect composition, measurements of protein and lipid content as well as lipid peroxidation were also performed. The results obtained indicate that the ectopic exposure to nanoparticles at 1 mg/cm² (TiO₂) and 0.5 mg/cm² (Al₂O₃) did not induce lethal toxicity in O. fasciatus, nor did it modify any of the reproductive parameters. However, NPs-TiO₂ and Al₂O₃ produced an increase in nymphal life span. In the parental generation NPs-TiO₂ increased protein content whereas NPs-Al₂O₃ decreased it. Several effects were detected in the filial generation as consequence of parental exposure. NPs-Al₂O₃ decreased protein content, NPs-TiO₂ decreased lipid content and Al₂O₃ in bulk form diminished protein content and increased lipid peroxidation. Responses observed in the individuals of the filial generation demonstrate the existence of trans-generational effects of NPs-Al₂O₃ and NPs-TiO_2.

Toxic and Genotoxic Effects of Silver Nanoparticles in Drosophila

The in vivo model Drosophila melanogaster was used here to determine the detrimental effects induced by silver nanoparticles (AgNPs) exposure. The main aim was to explore its interaction with the intestinal barrier and the genotoxic effects induced in hemocytes. The observed effects were compared with those obtained by silver nitrate, as an agent acting via the release of silver ions. Larvae were fed in food media containing both forms of silver. Results indicated that silver nitrate was more toxic than AgNPs when the viability "egg-to-adult" was determined. Depigmentation was observed in adults including those exposed to nontoxic concentrations, as indicative of exposure action. Interestingly, AgNPs were able to cross the intestinal barrier affecting hemocytes that show significant increases in the levels of intracellular reactive oxygen species. Additionally, significant levels of genotoxic damage, as determined by the comet assay, were also induced. When the expression of different stress-response genes was determined, for both AgNPs and silver nitrate, significant upregulation of Sod2 and p53 genes was observed. Our results confirm for the first time that in an in vivo model as Drosophila, AgNPs are able to cross the intestinal barriers and produce primary DNA damage (comet assay) via oxidative stress induction. In general, the effects induced by silver nitrate were more pronounced than those induced by AgNPs what would emphasize the role of silver ions in the observed effects. Environ. Mol. Mutagen. 60:277-285, 2019. © 2018 Wiley Periodicals, Inc.

Potential adverse effects of nanoparticles on the reproductive system

With the vigorous development of nanometer-sized materials, nanoproducts are becoming widely used in all aspects of life. In medicine, nanoparticles (NPs) can be used as nanoscopic drug carriers and for nanoimaging technologies. Thus, substantial attention has been paid to the potential risks of NPs. Previous studies have shown that numerous types of NPs are able to pass certain biological barriers and exert toxic effects on crucial organs, such as the brain, liver, and kidney. Only recently, attention has been directed toward the reproductive toxicity of nanomaterials. NPs can pass through the blood–testis barrier, placental barrier, and epithelial barrier, which protect reproductive tissues, and then accumulate in reproductive organs. NP accumulation damages organs (testis, epididymis, ovary, and uterus) by destroying Sertoli cells, Leydig cells, and germ cells, causing reproductive organ dysfunction that adversely affects sperm quality, quantity, morphology, and motility or reduces the number of mature oocytes and disrupts primary and secondary follicular development. In addition, NPs can disrupt the levels of secreted hormones, causing changes in sexual behavior. However, the current review primarily examines toxicological phenomena. The molecular mechanisms involved in NP toxicity to the reproductive system are not fully understood, but possible mechanisms include oxidative stress, apoptosis, inflammation, and genotoxicity. Previous studies have shown that NPs can increase inflammation, oxidative stress, and apoptosis and induce ROS, causing damage at the molecular and genetic levels which results in cytotoxicity. This review provides an understanding of the applications and toxicological effects of NPs on the reproductive system.

Mechanisms of (photo)toxicity of TiO2 nanomaterials (NM103, NM104, NM105): using high-throughput gene expression in Enchytraeus crypticus

Titanium dioxide (TiO2) based nanomaterials (NMs) are among the most produced NMs worldwide. When irradiated with light, particularly UV, TiO2 is photoactive, a property that is explored for several purposes. There are an increasing number of reports on the negative effects of photoactivated TiO2 on non-target organisms. We have here studied the effect of a suite of reference type TiO2 NMs (i.e. NM103, NM104, and NM105 and compared these to the bulk) with and without UV radiation to the oligochaete Enchytraeus crypticus. High-throughput gene expression was used to assess the molecular mechanisms, while also anchoring it to the known effects at the organism level (i.e., reproduction). Results showed that the photoactivity of TiO2 (UV exposed) played a major role in enhancing TiO2 toxicity, activating the transcription of oxidative stress, lysosome damage and apoptosis mechanisms. For non-UV activated TiO2, where toxicity at the organism level (reproduction) was lower, results showed potential for long-term effects (i.e., mutagenic and epigenetic). NM specific mechanisms were identified: NM103 affected transcription and translation, NM104_UV negatively affected the reproductive system/organs, and NM105_UV activated superoxide anion response. Results provided mechanistic information on UV-related phototoxicity of TiO2 materials and evidence for the potential long-term effects.

Translocation of silver nanoparticles in the ex vivo human placenta perfusion model characterized by single particle ICP-MS

With the extensive use of silver nanoparticles (AgNPs) in various consumer products their potential toxicity is of great concern especially for highly sensitive population groups such as pregnant women and even the developing fetus. To understand if AgNPs are taken up and cross the human placenta, we studied their translocation and accumulation in the human ex vivo placenta perfusion model by single particle ICP-MS (spICP-MS). The impact of different surface modifications on placental transfer was assessed by AgNPs with two different modifications: polyethylene glycol (AgPEG NPs) and sodium carboxylate (AgCOONa NPs). AgNPs and ionic Ag were detected in the fetal circulation in low but not negligible amounts. Slightly higher Ag translocation across the placental barrier for perfusion with AgPEG NPs and higher AgNP accumulation in placental tissue for perfusion with AgCOONa NPs were observed. Since these AgNPs are soluble in water, we tried to distinguish between the translocation of dissolved and particulate Ag. Perfusion with AgNO3 revealed the formation of Ag containing NPs in both circulations over time, of which the amount and their size in the fetal circulation were comparable to those from perfusion experiments with both AgNP types. Although we were not able to clarify whether intact AgNPs and/or Ag precipitates from dissolved Ag cross the placental barrier, our study highlights that uptake of Ag ions and/or dissolution of AgNPs in the tissue followed by re-precipitation in the fetal circulation needs to be considered as an important pathway in studies of AgNP translocation across biological barriers.

Effects on cytotoxicity and antibacterial properties of the incorporations of silver nanoparticles into the surface coating of dental alloys

The aim of this study was to research the changes in cytotoxicity and antibacterial properties after silver nanoparticles (AgNPs) were incorporated into the surface coating of dental alloys. AgNPs were attached to cobalt chromium alloys and pure titanium using a hydrothermal method, according to the reaction: AgNO₃+NaBH₄→ Ag+1/2H₂+1/2B₂H₆+NaNO₃. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity of the alloys when in contact with osteogenic precursor cells (MC3T3-E1) from mice and mesenchymal stem cells (BMSC) from rats. The antibacterial properties of dental alloys incorporating three different concentrations (10, 4, and 2 μmol/L) of AgNPs were tested on Staphylococcus aureus (SA) and Streptococcus mutans (MS). High cytotoxicity values were observed for all dental alloys that contained 0% of AgNPs (the control groups). The incorporation of AgNPs reduced cytotoxicity values. No significant difference was observed for antibacterial performance when comparing dental alloys containing AgNPs to the respective control groups. The results demonstrated that the cobalt chromium alloys and pure titanium all had cytotoxicity to MC3T3-E1 and BMSC and that the incorporation of AgNPs could reduce this cytotoxicity. The concentrations of AgNPs adopted in this study were found to have no antibacterial action against SA or MS.

Titanium dioxide nanoparticles: Toxicity and genotoxicity in Drosophila melanogaster (SMART eye-spot test and comet assay in neuroblasts)

Titanium dioxide nanoparticles (TiO₂NP) are used in the food, drug, and cosmetics industries and evaluation of their human and environmental toxicity is required. We have tested the toxicity of TiO₂NP (anatase) with respect to developmental effects and DNA damage in Drosophila melanogaster strain Ok, using the eye-spot Somatic Mutation and Recombination Test (SMART) and the comet assay (neuroblasts). For the survival assay, TiO₂NP were supplied to adult flies for 72 h and no adverse effects were seen. TiO₂NP were supplied chronically for the prolificacy, SMART, and comet assays. TiO₂NP increased fly prolificacy. With regard to genotoxicity, an increase was observed in the eye-spot SMART assay at 8 μg/mL dose, but not in the neuroblast comet assay for DNA damage.

Mode of action of nanoparticles against insects

The employment of nanoparticles obtained through various synthesis routes as novel pesticides recently attracted high research attention. An impressive number of studies have been conducted to test their toxic potential against a wide number of arthropod pests and vectors, with major emphasis on mosquitoes and ticks. However, precise information on the mechanisms of action of nanoparticles against insects and mites are limited, with the noteworthy exception of silica, alumina, silver, and graphene oxide nanoparticles on insects, while no information is available for mites. Here, I summarize current knowledge about the mechanisms of action of nanoparticles against insects. Both silver and graphene oxide nanoparticles have a significant impact on insect antioxidant and detoxifying enzymes, leading to oxidative stress and cell death. Ag nanoparticles also reduced acetylcholinesterase activity, while polystyrene nanoparticles inhibited CYP450 isoenzymes. Au nanoparticles can act as trypsin inhibitors and disrupt development and reproduction. Metal nanoparticles can bind to S and P in proteins and nucleic acids, respectively, leading to a decrease in membrane permeability, therefore to organelle and enzyme denaturation, followed by cell death. Besides, Ag nanoparticles up- and downregulate key insect genes, reducing protein synthesis and gonadotrophin release, leading to developmental damages and reproductive failure. The toxicity of SiO₂ and Al₂O₃ nanoparticles is due to their binding to the insect cuticle, followed by physico-sorption of waxes and lipids, leading to insect dehydration. In the final section, insect nanotoxicology research trends are critically discussed, outlining major challenges to predict the ecotoxicological consequences arising from the real-world use of nanoparticles as pesticides.

Titanium dioxide nanoparticle exposure alters metabolic homeostasis in a cell culture model of the intestinal epithelium and Drosophila melanogaster

Nanosized titanium dioxide (TiO₂) is a common additive in food and cosmetic products. The goal of this study was to investigate if TiO₂ nanoparticles affect intestinal epithelial tissues, normal intestinal function, or metabolic homeostasis using in vitro and in vivo methods. An in vitro model of intestinal epithelial tissue was created by seeding co-cultures of Caco-2 and HT29-MTX cells on a Transwell permeable support. These experiments were repeated with monolayers that had been cultured with the beneficial commensal bacteria Lactobacillus rhamnosus GG (L. rhamnosus). Glucose uptake and transport in the presence of TiO₂ nanoparticles was assessed using fluorescent glucose analog 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG). When the cell monolayers were exposed to physiologically relevant doses of TiO₂, a statistically significant reduction in glucose transport was observed. These differences in glucose absorption were eliminated in the presence of beneficial bacteria. The decrease in glucose absorption was caused by damage to intestinal microvilli, which decreased the surface area available for absorption. Damage to microvilli was ameliorated in the presence of L. rhamnosus. Complimentary studies in Drosophila melanogaster showed that TiO₂ ingestion resulted in decreased body size and glucose content. The results suggest that TiO₂ nanoparticles alter glucose transport across the intestinal epithelium, and that TiO₂ nanoparticle ingestion may have physiological consequences.

Maternal exposure to silver nanoparticles are associated with behavioral abnormalities in adulthood: Role of mitochondria and innate immunity in developmental toxicity

Silver nanoparticles (Ag-NPs) are currently used in a wide range of consumer products. Considering the small size of Ag-NPs, they are able to pass through variety of biological barriers and exert their effects. In this regard, the unique physicochemical properties of Ag-NPs along with its high application in the industry have raised concerns about their negative effects on human health. Therefore, it investigated whether prenatal exposure to low doses of Ag-NPs is able to induce any abnormality in the cognitive and behavioral performance of adult offspring. We gavaged pregnant NMRI mice with, 1) Deionized water as vehicle, 2) Ag-NPs 10 nm (0.26 mg/kg/day), 3) Ag-NPs 30 nm (0.26 mg/kg/day), and 4) AgNO₃ (0.26 mg/kg/day) from gestational day (GD) 0 until delivery day. At the postnatal day (PD) 1, our results showed that high concentration of silver is present in the brain of pups. Further, we observed mitochondrial dysfunction and upregulation of the genes relevant to innate immune system in the brain. At PD 60, results revealed that prenatal exposure to Ag-NPs provoked severe cognitive and behavioral abnormalities in male offspring. In addition, we found that prenatal exposure to Ag-NPs was associated with abnormal mitochondrial function and significant up-regulation of the genes relevant to innate immunity in the brain. Although the Ag-NPs have been considered as safe compounds at low doses, our results indicate that prenatal exposure to low doses of Ag-NPs is able to induce behavioral and cognitive abnormalities in adulthood. Also, we found that these effects are at least partly associated with hippocampal mitochondrial dysfunction and the activation of sterile inflammation during early stages of life.

Gestational exposure to titanium dioxide nanoparticles impairs the placentation through dysregulation of vascularization, proliferation and apoptosis in mice

Background

Titanium dioxide nanoparticles (TiO₂ NPs) have recently found applications in a wide variety of consumer goods. TiO₂ NPs exposure significantly increases fetal deformities and mortality. However, the potential toxicity of TiO₂ NPs on the growth and development of placenta has been rarely studied during mice pregnancy.

Purpose

The objective of this study was to investigate the effects of maternal exposure of TiO₂ NPs on the placentation.

Methods

Mice were administered TiO₂ NPs by gavage at 0, 1 and 10 mg/kg/day from gestational day (GD) 1 to GD 13. Uteri and placentas from these mice were collected and counted the numbers of implanted and resorbed embryo and measured the placental weight on GD 13. Placental morphometry was observed by hematoxylin and eosin staining. The levels of Hand1, Esx1, Eomes, Hand2, Ascl2 and Fra1 mRNA were assessed by qRT-PCR. Uterine NK (uNK) cells were detected by using DBA lectin. Laminin immunohistochemical staining was to identify fetal vessels. Western blotting and transmission electron micrograph (TEM) were used to assess the apoptosis of placenta.

Results

No treatment-related difference was observed in the numbers of implanted and resorbed embryos and weight of placenta between the groups. However, 1 mg/kg/day TiO₂ NPs treatment significantly reduced the ratio of placenta/body weight on GD 13. The proportion of spongiotrophoblast in the 10 mg/kg/day dose group became higher than that in the control group, yet that of labyrinth was significantly lower in 10 mg/kg/day mice. The expression levels of Hand1, Esx1, Eomes, Hand2, Ascl2 and Fra1 mRNA markedly decreased in TiO₂ NP treated placentas. Furthermore, TiO₂ NPs treatment impaired the formation of intricate networks of fetal vessels and reduced the number of uNK cells, and inhibited proliferation and induced apoptosis of placenta by nuclear pyknosis, the activation of caspase-3 and upregulation of Bax protein and downregulation of Bcl-2 protein on GD 13.

Conclusion

Gestational exposure to TiO₂ NPs significantly impairs the growth and development of placenta in mice, with a mechanism that seems to be involved in the dysregulation of vascularization, proliferation and apoptosis. Therefore, our results suggested the need for great caution while handling of the nanomaterials by workers and specially pregnant consumers.