Exposure of pregnant mice to carbon black by intratracheal instillation: toxicogenomic effects in dams and offspring

Microvascular and mitochondrial dysfunction in the female F1 generation after gestational TiO2 nanoparticle exposure

Due to the ongoing evolution of nanotechnology, there is a growing need to assess the toxicological outcomes in under-studied populations in order to properly consider the potential of engineered nanomaterials (ENM) and fully enhance their safety. Recently, we and others have explored the vascular consequences associated with gestational nanomaterial exposure, reporting microvascular dysfunction within the uterine circulation of pregnant dams and the tail artery of fetal pups. It has been proposed (via work derived by the Barker Hypothesis) that mitochondrial dysfunction and subsequent oxidative stress mechanisms as a possible link between a hostile gestational environment and adult disease. Therefore, in this study, we exposed pregnant Sprague-Dawley rats to nanosized titanium dioxide aerosols after implantation (gestational day 6). Pups were delivered, and the progeny grew into adulthood. Microvascular reactivity, mitochondrial respiration and hydrogen peroxide production of the coronary and uterine circulations of the female offspring were evaluated. While there were no significant differences within the maternal or litter characteristics, endothelium-dependent dilation and active mechanotransduction in both coronary and uterine arterioles were significantly impaired. In addition, there was a significant reduction in maximal mitochondrial respiration (state 3) in the left ventricle and uterus. These studies demonstrate microvascular dysfunction and coincide with mitochondrial inefficiencies in both the cardiac and uterine tissues, which may represent initial evidence that prenatal ENM exposure produces microvascular impairments that persist throughout multiple developmental stages.

A perspective on the developmental toxicity of inhaled nanoparticles

This paper aimed to clarify whether maternal inhalation of engineered nanoparticles (NP) may constitute a hazard to pregnancy and fetal development, primarily based on experimental animal studies of NP and air pollution particles. Overall, it is plausible that NP may translocate from the respiratory tract to the placenta and fetus, but also that adverse effects may occur secondarily to maternal inflammatory responses. The limited database describes several organ systems in the offspring to be potentially sensitive to maternal inhalation of particles, but large uncertainties exist about the implications for embryo-fetal development and health later in life. Clearly, the potential for hazard remains to be characterized. Considering the increased production and application of nanomaterials and related consumer products a testing strategy for NP should be established. Due to large gaps in data, significant amounts of groundwork are warranted for a testing strategy to be established on a sound scientific basis.

Effect of maternal exposure to carbon black nanoparticle during early gestation on the splenic phenotype of neonatal mouse

Maternal exposure to environmental factors is implicated as a major factor in the development of the immune system in newborns. Newborns are more susceptible to microbial infection because their immune system is immature. Development of lymphocytes reflects an innate program of lymphocyte proliferation. The aim of this study was to investigate the effects of maternal exposure to carbon black nanoparticle (CB-NP) during early gestation on the development of lymphoid tissues in infantile mice. Pregnant ICR mice were treated with a suspension of CB-NP (95 μg kg(-1) time(-1)) by intranasal instillation on gestational day 5 and 9. Spleen tissues were collected from offspring mice at 1, 3, 5, and 14 days postpartum. Splenocyte phenotypes were examined by investigating the pattern of surface molecules using flow cytometry. Gene expression in the spleen was examined by quantitative RT-PCR. CD3(+) (T), CD4(+) and CD8(+) cells were decreased in the spleen of 1-5-day-old offspring in the treated group. Expression level of Il15 was significantly increased in the spleen of newborn male offspring, and Ccr7 and Ccl19 were increased in the spleen of female offspring in the CB-NP group. Splenic mRNA change profiles by CBNP were similar between male and female offspring. This article concluded that exposure of pregnant mothers to CB-NP partially suppressed the development of the immune system of offspring mice. The decrease in splenic T cells in the treated group recovered at 14 days after birth. This is the first report of developmental effect of nanoparticle on the lymphatic phenotype.

Intratracheally instilled titanium dioxide nanoparticles translocate to heart and liver and activate complement cascade in the heart of C57BL/6 mice

An estimated 1% or less of nanoparticles (NPs) deposited in the lungs translocate to systemic circulation and enter other organs; however, this estimation may not be accurate given the low sensitivity of existing in vivo NP detection methods. Moreover, the biological effects of such low levels of translocation are unclear. We employed a nano-scale hyperspectral microscope to spatially observe and spectrally profile NPs in tissues and blood following pulmonary deposition in mice. In addition, we characterized effects occurring in blood, liver and heart at the mRNA and protein level following translocation from the lungs. Adult female C57BL/6 mice were exposed via intratracheal instillation to 18 or 162 µg of industrially relevant titanium dioxide nanoparticles (nano-TiO2) alongside vehicle controls. Using the nano-scale hyperspectral microscope, translocation to heart and liver was confirmed at both doses, and to blood at the highest dose, in mice analyzed 24 h post-exposure. Global gene expression profiling and ELISA analysis revealed activation of complement cascade and inflammatory processes in heart and specific activation of complement factor 3 in blood, suggesting activation of an early innate immune response essential for particle opsonisation and clearance. The liver showed a subtle response with changes in the expression of genes associated with acute phase response. This study characterizes the subtle systemic effects that occur in liver and heart tissues following pulmonary exposure and low levels of translocation of nano-TiO2 from lungs.

Transcriptional profiling identifies physicochemical properties of nanomaterials that are determinants of the in vivo pulmonary response

We applied transcriptional profiling to elucidate the mechanisms associated with pulmonary responses to titanium dioxide (TiO2 ) nanoparticles (NPs) of different sizes and surface coatings, and to determine if these responses are modified by NP size, surface area, surface modification, and embedding in paint matrices. Adult C57BL/6 mice were exposed via single intratracheal instillations to free forms of TiO2 NPs (10, 20.6, or 38 nm in diameter) with different surface coatings, or TiO2 NPs embedded in paint matrices. Controls were exposed to dispersion medium devoid of NPs. TiO2 NPs were characterized for size, surface area, chemical impurities, and agglomeration state in the exposure medium. Pulmonary transcriptional profiles were generated using microarrays from tissues collected one and 28 d postexposure. Property-specific pathway effects were identified. Pulmonary protein levels of specific inflammatory cytokines and chemokines were confirmed by ELISA. The data were collapsed to 659 differentially expressed genes (P ≤ 0.05; fold change ≥ 1.5). Unsupervised hierarchical clustering of these genes revealed that TiO2 NPs clustered mainly by postexposure timepoint followed by particle type. A pathway-based meta-analysis showed that the combination of smaller size, large deposited surface area, and surface amidation contributes to TiO2 NP gene expression response. Embedding of TiO2 NP in paint dampens the overall transcriptional effects. The magnitude of the expression changes associated with pulmonary inflammation differed across all particles; however, the underlying pathway perturbations leading to inflammation were similar, suggesting a generalized mechanism-of-action for all TiO2 NPs. Thus, transcriptional profiling is an effective tool to determine the property-specific biological/toxicity responses induced by nanomaterials.

Do all roads lead to Rome? The role of neuro-immune interactions before birth in the programming of offspring obesity

The functions of the nervous system can be powerfully modulated by the immune system. Although traditionally considered to be quite separate, neuro-immune interactions are increasingly recognized as critical for both normal and pathological nervous system function in the adult. However, a growing body of information supports a critical role for neuro-immune interactions before birth, particularly in the prenatal programming of later-life neurobehavioral disease risk. This review will focus on maternal obesity, as it represents an environment of pathological immune system function during pregnancy that elevates offspring neurobehavioral disease risk. We will first delineate the normal role of the immune system during pregnancy, including the role of the placenta as both a barrier and relayer of inflammatory information between the maternal and fetal environments. This will be followed by the current exciting findings of how immuno-modulatory molecules may elevate offspring risk of neurobehavioral disease by altering brain development and, consequently, later life function. Finally, by drawing parallels with pregnancy complications other than obesity, we will suggest that aberrant immune activation, irrespective of its origin, may lead to neuro-immune interactions that otherwise would not exist in the developing brain. These interactions could conceivably derail normal brain development and/or later life function, and thereby elevate risk for obesity and other neurobehavioral disorders later in the offspring's life.

Maternal Lipopolysaccharide Exposure Promotes Immunological Functional Changes in Adult Offspring CD4+ T Cells

PROBLEM

Maternal immune activation (MIA) is a risk factor for autism and schizophrenia. However, how MIA affects offspring immune function remains unknown.

METHOD OF STUDY

To investigate the effect of MIA on the offspring, pregnant C57BL/6J mice were given an intraperitoneal injection of 50 μg/kg lipopolysaccharide (LPS) on gestational day 12.5.

RESULTS

Adult LPS-treated offspring were hyper-reactive to LPS, and enhanced tumor necrosis factor-α production was observed. CD4+ T cells from LPS offspring had an elevated percentage of interferon (IFN)-γ(+) CD4+ T cells and interleukin (IL)-17A+ CD4+ T cells in the spleen, IL-17A+ CD4+ T cells in the liver, and CD4+ Foxp3+ T cells in the spleen. LPS offspring CD4+ T cells showed increased proliferation and an enhanced survival rate. DNA microarray analysis of resting LPS offspring CD4+ T cells identified eight up-regulated genes, most of which encoded transcription factors. Quantitative liquid chromatography-mass spectrometry identified 18 up-regulated proteins in resting LPS offspring CD4+ T cells and five up-regulated proteins in activated LPS offspring CD4+ T cells, most of which participated in the PANTHER Gene Ontology metabolic process.

CONCLUSIONS

Our results showed that MIA to LPS up-regulated proteins involved in metabolic process in CD4+ T cells from LPS offspring that might contribute to the hyperactivated immune response of adult LPS offspring.

DNA damage following pulmonary exposure by instillation to low doses of carbon black (Printex 90) nanoparticles in mice

We previously observed genotoxic effects of carbon black nanoparticles at low doses relative to the Danish Occupational Exposure Limit (3.5 mg/m(3)). Furthermore, DNA damage occurred in broncho-alveolar lavage (BAL) cells in the absence of inflammation, indicating that inflammation is not required for the genotoxic effects of carbon black. In this study, we investigated inflammatory and acute phase response in addition to genotoxic effects occurring following exposure to nanoparticulate carbon black (NPCB) at even lower doses. C57BL/6JBomTac mice were examined 1, 3, and 28 days after a single instillation of 0.67, 2, 6, and 162 µg Printex 90 NPCB and vehicle. Cellular composition and protein concentration was evaluated in BAL fluid as markers of inflammatory response and cell damage. DNA strand breaks in BAL cells, lung, and liver tissue were assessed using the alkaline comet assay. The pulmonary acute phase response was analyzed by Saa3 mRNA real-time quantitative PCR. Instillation of the low doses of NPCB induced a slight neutrophil influx one day after exposure. Pulmonary exposure to small doses of NPCB caused an increase in DNA strand breaks in BAL cells and lung tissue measured using the comet assay. We interpret the increased DNA strand breaks occurring following these low exposure doses of NPCB as DNA damage caused by primary genotoxicity in the absence of substantial inflammation, cell damage, and acute phase response.

MWCNTs of different physicochemical properties cause similar inflammatory responses, but differences in transcriptional and histological markers of fibrosis in mouse lungs

Multi-walled carbon nanotubes (MWCNTs) are an inhomogeneous group of nanomaterials that vary in lengths, shapes and types of metal contamination, which makes hazard evaluation difficult. Here we present a toxicogenomic analysis of female C57BL/6 mouse lungs following a single intratracheal instillation of 0, 18, 54 or 162 μg/mouse of a small, curled (CNT(Small), 0.8 ± 0.1 μm in length) or large, thick MWCNT (CNT(Large), 4 ± 0.4 μm in length). The two MWCNTs were extensively characterized by SEM and TEM imaging, thermogravimetric analysis, and Brunauer-Emmett-Teller surface area analysis. Lung tissues were harvested 24h, 3 days and 28 days post-exposure. DNA microarrays were used to analyze gene expression, in parallel with analysis of bronchoalveolar lavage fluid, lung histology, DNA damage (comet assay) and the presence of reactive oxygen species (dichlorodihydrofluorescein assay), to profile and characterize related pulmonary endpoints. Overall changes in global transcription following exposure to CNT(Small) or CNT(Large) were similar. Both MWCNTs elicited strong acute phase and inflammatory responses that peaked at day 3, persisted up to 28 days, and were characterized by increased cellular influx in bronchoalveolar lavage fluid, interstitial pneumonia and gene expression changes. However, CNT(Large) elicited an earlier onset of inflammation and DNA damage, and induced more fibrosis and a unique fibrotic gene expression signature at day 28, compared to CNT(Small). The results indicate that the extent of change at the molecular level during early response phases following an acute exposure is greater in mice exposed to CNT(Large), which may eventually lead to the different responses observed at day 28.

Effects of prenatal exposure to single-wall carbon nanotubes on reproductive performance and neurodevelopment in mice

Carbon nanotubes with extraordinary properties may become a novel drug and gene delivery tool in nanomedicine; however, insufficient information is available regarding their biosafety. Therefore, this work was performed to study the effect of prenatal exposure of single-walled carbon nanotubes (SWCNTs) on reproductive and neurobehavioral endpoints in mice. Thirty pregnant female mice were assigned to three groups ( n = 10 for each group). The two treated groups were injected intraperitoneally (i.p.) with 1 or 10 mg/kg body weight (b.w.) of SWCNTs suspended in 1 ml of phosphate buffer saline (PBS) on gestational days 0 and 3. The control group was injected i.p. with an equal volume of PBS. The neurobehavioral ontogeny of pups was evaluated using a modified Fox battery. A decrease in litter size on postnatal day 2 was observed in the group treated with 10 mg/kg b.w. of SWCNTs whereas no significant differences between groups were observed in any other parameters. The behavioral development of pups did not show significant differences during growth except for the surface righting reflex, which showed significant delay compared to control in the group treated with 1 mg/kg b.w. SWCNTs. Moreover, exposed offspring (10 mg/kg b.w. SWCNTs) displayed enhanced anxiety in the elevated plus maze; however, other ethological analysis (Morris water maze and open field test) did not show behavioral changes in the experimental groups. In conclusion, the present results demonstrated small changes in offspring sensory and motor development following exposure to SWCNTs and support the idea that SWCNT risk assessment merits further investigation.

The heritable effects of nanotoxicity

The widespread entry of nanomaterials into manifold life fields posed serious concerns on environmental health and safety issues. Potential adverse effects of nanoparticles (NPs) are continuously faced using in vitro cell systems and by mean of cell and molecular biology tools, several mechanisms have been found beyond their toxicity. The evaluation of the in vivo possible consequences derived from exposure of living organisms to NPs is instead more complex but compulsory in view of their application for diagnosis or therapeutic purposes. Here the effects of NP-induced genetic alteration on the progeny of treated animals will be treated, considering selected species from invertebrate and vertebrates as examples of transgenerational transmission of NP toxicity. The effects on reproductive capability, fertility and embryogenesis observed in different animal species upon treatment with different materials will provide an overview of the current knowledge on the heritable feature of nanotoxicity.

PVP formulated fullerene (C60) increases Rho-kinase dependent vascular tissue contractility in pregnant Sprague Dawley rats

Pregnancy is a unique physiological state, in which C60 fullerene is reported to be distributed in both maternal and fetal tissues. Tissue distribution of C60 differs between pregnant and non-pregnant states, presumably due to functional changes in vasculature during pregnancy. We hypothesized that polyvinylpyrrolidone (PVP) formulated C60 (C60/PVP) increases vascular tissue contractility during pregnancy by increasing Rho-kinase activity. C60/PVP was administered intravenously to pregnant and non-pregnant female Sprague Dawley rats. Vascular responses were assessed using wire myography 24h post-exposure. Increased stress generation was observed in uterine artery, thoracic aorta and umbilical vein. Rho-Rho-kinase mediated force maintenance was increased in arterial segments from C60/PVP exposed pregnant rats when compared to PVP exposed rats. Our findings suggest that intravenous exposure to C60/PVP during pregnancy increases vascular tissue contractility of the uterine artery through elements of Rho-Rho-kinase signaling during late stages of pregnancy.

Toxicological effect of engineered nanomaterials on the liver

The liver has a crucial role in metabolic homeostasis, as it is responsible for the storage, synthesis, metabolism and redistribution of carbohydrates, fats and vitamins, and numerous essential proteins. It is also the principal detoxification centre of the body, removing xenobiotics and waste products by metabolism or biliary excretion. An increasing number of studies have shown that some nanomaterials (NMs) are capable of distributing from the site of exposure (e.g. lungs, gut) to a number of secondary organs, including the liver. As a secondary exposure site the liver has been shown to preferentially accumulate NMs (>90% of translocated NMs compared with other organs), and alongside the kidneys may be responsible for the clearance of NMs from the blood. Research into the toxicity posed by NMs to the liver is expanding due to the realization that NMs accumulate in this organ following exposure via a variety of routes (e.g. ingestion, injection and inhalation). Thus it is critical to consider what advances have been made in the investigation of NM hepatotoxicity, as well as appraising the quality of the information available and gaps in the knowledge that still exist. The overall aim of this review is to outline what data are available in the literature for the toxicity elicited by NMs to the liver in order to establish a weight of evidence approach (for risk assessors) to inform on the potential hazards posed by NMs to the liver.

Particle-induced pulmonary acute phase response may be the causal link between particle inhalation and cardiovascular disease

Inhalation of ambient and workplace particulate air pollution is associated with increased risk of cardiovascular disease. One proposed mechanism for this association is that pulmonary inflammation induces a hepatic acute phase response, which increases risk of cardiovascular disease. Induction of the acute phase response is intimately linked to risk of cardiovascular disease as shown in both epidemiological and animal studies. Indeed, blood levels of acute phase proteins, such as C-reactive protein and serum amyloid A, are independent predictors of risk of cardiovascular disease in prospective epidemiological studies. In this review, we present and review emerging evidence that inhalation of particles (e.g., air diesel exhaust particles and nanoparticles) induces a pulmonary acute phase response, and propose that this induction constitutes the causal link between particle inhalation and risk of cardiovascular disease. Increased levels of acute phase mRNA and proteins in lung tissues, bronchoalveolar lavage fluid and plasma clearly indicate pulmonary acute phase response following pulmonary deposition of different kinds of particles including diesel exhaust particles, nanoparticles, and carbon nanotubes. The pulmonary acute phase response is dose-dependent and long lasting. Conversely, the hepatic acute phase response is reduced relative to lung or entirely absent. We also provide evidence that pulmonary inflammation, as measured by neutrophil influx, is a predictor of the acute phase response and that the total surface area of deposited particles correlates with the pulmonary acute phase response. We discuss the implications of these findings in relation to occupational exposure to nanoparticles.

How to cite this article: WIREs Nanomed Nanobiotechnol 2014, 6:517–531. doi: 10.1002/wnan.1279

Damaging effects of multi-walled carbon nanotubes on pregnant mice with different pregnancy times

The mechanism by which nanoparticles cross the placental barrier was studied by using isotopic tracers. The abortion rates and other related data were counted and analysed in pregnant mice with different pregnancy times. Results showed that oxidised multi-walled carbon nanotubes (oMWCNTs) crossed the placental barrier and entered the foetus body. The abortion rates in the pregnant mice depended on pregnancy times. The abortion rates in the first-time, second-time and fourth-time pregnant mice were 70%, 40% and 50%, respectively. The maternal body weight gain was inhibited until gestational ages of 13, 10 and 11 d. oMWCNTs decreased the serum progesterone level and increased the serum oestradiol level in a dose- and time-dependent manner. However, this effect decreased with gestational age. The histology and vascular endothelial growth factor/reactive oxygen species content in the placenta showed that oMWCNTs narrowed the blood vessel and decreased the number of blood vessels in the placenta.

Nanotoxicity overview: nano-threat to susceptible populations

Due to the increasing applications of nanomaterials and nanotechnology, potential danger of nanoparticle exposure has become a critical issue. However, recent nanotoxicity studies have mainly focused on the health risks to healthy adult population. The nanotoxicity effects on susceptible populations (such as pregnant, neonate, diseased, and aged populations) have been overlooked. Due to the alterations in physiological structures and functions in susceptible populations, they often suffer more damage from the same exposure. Thus, it is urgent to understand the effects of nanoparticle exposure on these populations. In order to fill this gap, the potential effects of nanoparticles to pregnant females, neonate, diseased, and aged population, as well as the possible underlying mechanisms are reviewed in this article. Investigations show that responses from susceptible population to nanoparticle exposure are often more severe. Reduced protection mechanism, compromised immunity, and impaired self-repair ability in these susceptible populations may contribute to the aggravated toxicity effects. This review will help minimize adverse effects of nanoparticles to susceptible population in future nanotechnology applications.

Noninvasive intratracheal intubation to study the pathology and physiology of mouse lung

The use of a model that mimics the condition of lung diseases in humans is critical for studying the pathophysiology and/or etiology of a particular disease and for developing therapeutic intervention. With the increasing availability of knockout and transgenic derivatives, together with a vast amount of genetic information, mice provide one of the best models to study the molecular mechanisms underlying the pathology and physiology of lung diseases. Inhalation, intranasal instillation, intratracheal instillation, and intratracheal intubation are the most widely used techniques by a number of investigators to administer materials of interest to mouse lungs. There are pros and cons for each technique depending on the goals of a study. Here a noninvasive intratracheal intubation method that can directly deliver exogenous materials to mouse lungs is presented. This technique was applied to administer bleomycin to mouse lungs as a model to study pulmonary fibrosis.

Particle-induced pulmonary acute phase response correlates with neutrophil influx linking inhaled particles and cardiovascular risk

BACKGROUND

Particulate air pollution is associated with cardiovascular disease. Acute phase response is causally linked to cardiovascular disease. Here, we propose that particle-induced pulmonary acute phase response provides an underlying mechanism for particle-induced cardiovascular risk.

METHODS

We analysed the mRNA expression of Serum Amyloid A (Saa3) in lung tissue from female C57BL/6J mice exposed to different particles including nanomaterials (carbon black and titanium dioxide nanoparticles, multi- and single walled carbon nanotubes), diesel exhaust particles and airborne dust collected at a biofuel plant. Mice were exposed to single or multiple doses of particles by inhalation or intratracheal instillation and pulmonary mRNA expression of Saa3 was determined at different time points of up to 4 weeks after exposure. Also hepatic mRNA expression of Saa3, SAA3 protein levels in broncheoalveolar lavage fluid and in plasma and high density lipoprotein levels in plasma were determined in mice exposed to multiwalled carbon nanotubes.

RESULTS

Pulmonary exposure to particles strongly increased Saa3 mRNA levels in lung tissue and elevated SAA3 protein levels in broncheoalveolar lavage fluid and plasma, whereas hepatic Saa3 levels were much less affected. Pulmonary Saa3 expression correlated with the number of neutrophils in BAL across different dosing regimens, doses and time points.

CONCLUSIONS

Pulmonary acute phase response may constitute a direct link between particle inhalation and risk of cardiovascular disease. We propose that the particle-induced pulmonary acute phase response may predict risk for cardiovascular disease.

In utero exposure to nanosized carbon black (Printex90) does not induce tandem repeat mutations in female murine germ cells

Inhalation of particles has been shown to induce mutations in the male germline in mice following both prenatal and adult exposures in several experiments. In contrast, the effects of particles on female germ cell mutagenesis are not well established. Germline mutations are induced during active cell division, which occurs during fetal development in females. We investigated the effects of prenatal exposure to carbon black nanoparticles (CB) on induction of mutations in the female mouse germline during fetal development, spanning the critical developmental stages of oogenesis. Pregnant C57BL/6J mice were exposed four times during gestation by intratracheal instillation of 67μg/animal of nanosized carbon black Printex90 or vehicle (gestation days 7, 10, 15 and 18). Female offspring were raised to maturity and mated with unexposed CBA males. Expanded simple tandem repeat (ESTR) germline mutation rates in the resulting F2 generation were determined from full pedigrees (mother, father, offspring) of F1 female mice (178 CB-exposed and 258 control F2 offspring). ESTR mutation rates in CB-exposed F2 female offspring were not statistically different from those of F2 female control offspring.

Interactions of engineered nanoparticles with organs protected by internal biological barriers

Engineered nanomaterials may exert adverse effects on human health which, in turn, may be linked to their propensity to cross biological barriers in the body. Here, available evidence is discussed, based on in vivo studies for interactions of commercially relevant nanoparticles with critical internal barriers. The internal barriers in focus in this review are the blood-brain barrier, protecting the brain, the blood-testis barrier, protecting the male germ line, and the placenta, protecting the developing fetus. The route of exposure (pulmonary, gastro-intestinal, intravenous, intraperitoneal, dermal), and, hence, the portal of entry of nanoparticles into the body, is of critical importance. Different physico-chemical properties, not only size, may determine the ability of nanoparticles to breach biological barriers; the situation is further compounded by the formation of a so-called corona of biomolecules on the surfaces of nanoparticles, the composition of which may vary depending on the route of exposure and the translocation of nanoparticles from one biological compartment to another. The relevance of nanoparticle interactions with internal biological barriers for their impact on the organs protected by these barriers is also discussed.

Daily sperm production: application in studies of prenatal exposure to nanoparticles in mice

We investigated the influence of maternal airway exposure to nanoparticulate titanium dioxide (TiO₂, UV-Titan) and carbon black (CB, Printex90), on male reproductive function in the two following generations. Time-mated C57BL/6J mice were exposed by inhalation to UV-Titan, or by intratracheal instillation with Printex90. Body and testicle weight, sperm content per g testicular parenchyma and daily sperm production (DSP) were assessed. The protocol for assessment of DSP was optimized for application in mice (C57BL/6J) and the influence of different parameters was studied. Maternal particulate exposure did not affect DSP statistically significantly in the F1 generation, although TiO₂ tended to reduce sperm counts. Overall, time-to-first F2 litter increased with decreasing sperm production. There was no effect on sperm production in the F2 generation originating after TiO₂ exposure. F2 offspring, whose fathers were prenatally exposed to Printex90, showed lowered sperm production. Furthermore, we report statistically significant differences in sperm production between mouse strains.

Hepatic and pulmonary toxicogenomic profiles in mice intratracheally instilled with carbon black nanoparticles reveal pulmonary inflammation, acute phase response, and alterations in lipid homeostasis

Global pulmonary and hepatic messenger RNA profiles in adult female C57BL/6 mice intratracheally instilled with carbon black nanoparticles (NPs) (Printex 90) were analyzed to identify biological perturbations underlying systemic responses to NP exposure. Tissue gene expression changes were profiled 1, 3, and 28 days following exposure to 0.018, 0.054, and 0.162 mg Printex 90 alongside controls. Pulmonary response was marked by increased expression of inflammatory markers and acute phase response (APR) genes that persisted to day 28 at the highest exposure dose. Genes in the 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase pathway were increased, and those involved in cholesterol efflux were decreased at least at the highest dose on days 1 and 3. Hepatic responses mainly consisted of the HMG-CoA reductase pathway on days 1 (high dose) and 28 (all doses). Protein analysis in tissues and plasma of 0.162 mg Printex 90-exposed mice relative to control revealed an increase in plasma serum amyloid A on days 1 and 28 (p < 0.05), decreases in plasma high-density lipoprotein on days 3 and 28, an increase in plasma low-density lipoprotein on day 28 (p < 0.05), and marginal increases in total hepatic cholesterol on day 28 (p = 0.06). The observed changes are linked to APR. Although further research is needed to establish links between observations and the onset and progression of systemic disorders, the present study demonstrates the ability of NPs to induce systemic effects.