Induction of size-dependent breakdown of blood-milk barrier in lactating mice by TiO2 nanoparticles

Multigenerational inheritance of breathing deficits following perinatal exposure to titanium dioxide nanoparticles in the offspring of mice

BACKGROUND

The utilization of titanium dioxide nanoparticles (TIO2NPs) has experienced a significant surge in recent decades, and these particles are now commonly found in various everyday consumer products. Due to their small size, TIO2NPs can penetrate biological barriers and elicit adverse interactions with biological tissues. Notably, exposure of pregnant females to TIO2NPs during the perinatal period has been shown to disrupt the growth of offspring. Furthermore, this exposure induces epigenetic modifications in the DNA of newborns, suggesting the possibility of multigenerational effects. Thus, perinatal exposure to TIO2NPs may induce immediate metabolic impairments in neonates, which could be transmitted to subsequent generations in the long term.

RESULTS

In this study, we utilized perinatal exposure of female mice to TIO2NPs through voluntary food intake and observed impaired metabolism in newborn male and female F1 offspring. The exposed newborn mice exhibited reduced body weight gain and a slower breathing rate compared to non-exposed animals. Additionally, a higher proportion of exposed F1 newborns experienced apneas. Similar observations were made when the exposure was limited to the postnatal period, highlighting lactation as a critical period for the adverse effects of TIO2NPs on postnatal metabolism. Importantly, the breathing deficits induced by TIO2NPs were transmitted from F1 females to the subsequent F2 generation. Moreover, re-exposure of adult F1 females to TIO2NPs exacerbated the breathing deficits in newborn F2 males.

CONCLUSIONS

Our findings demonstrate that perinatal exposure to TIO2NPs disrupts postnatal body weight gain and respiration in the offspring, and these deficits are transmissible to future generations.

Engineered nanomaterials induce alterations in biological barriers: focus on paracellular permeability

Engineered nanoparticles (ENPs) are widely used in medical diagnosis and treatment, as food additives and as energy materials. ENPs may exert adverse or beneficial effects on the human body, which may be linked to interactions with biological barriers. In this review, the authors summarize the influences of four typical metal/metal oxide nanomaterials (Ag, TiO₂, Au, ZnO nanoparticles) on the paracellular permeability of biological barriers. Disruptions on tight junctions, adhesion junctions, gap junctions and desmosomes via complex signaling pathways, such as the MAPK, PKC and ROCK signaling pathways, affect paracellular permeability. Reactive oxygen species and cytokines underlie the mechanism of ENP-triggered alterations in paracellular permeability. This review provides the information necessary for the cautious application of nanoparticles in medicine and life sciences in the future.

GPR109A alleviate mastitis and enhances the blood milk barrier by activating AMPK/Nrf2 and autophagy

Mastitis causes great psychological and physical pain among women. Our previous studies found that niacin has anti-inflammatory effect, and the realization of this function depends on GPR109A. However, there are no previous reports about the anti-inflammatory function of GPR109A in mastitis. In our study, we observed the effect of niacin on the WT and GPR109A^-/- mice mastitis model. The results showed that administration of niacin to WT mice reduced the damage, proinflammatory mediators and protected the integrity of the blood milk barrier in mammary gland. While in GPR109A^-/- mice, there was no effect on the above indexes. In mammary epithelial cells, GPR109A was able to promote autophagy and Nrf2 nuclear import through AMPK. In LPS-induced mammary epithelial cells, niacin inhibited the LPS-induced inflammatory response and downregulation of tight junction proteins, and these effects were eliminated by knocking down GPR109A, blocking autophagy or inhibiting Nrf2 nuclear import. These results indicate that in mastitis, GPR109A promotes autophagy and Nrf2 nuclear import through AMPK, thereby inhibiting inflammatory damage to the mammary gland and repairing the blood milk barrier. Our results suggested that GPR109A may be a potential target for the treatment of mastitis.

Ovarian toxicity of nanoparticles

The ovary is a highly important organ for female reproduction. The main functions include sex steroid hormone synthesis, follicular development, and achievement of oocyte meiotic and development competence for proper fertilization. Nanoparticle (NP) exposure is becoming unavoidable because of its wide use in different products, including cosmetics, food, health, and personal care products. Studies examining different nonreproductive tissues or systems have shown that characteristics such as the size, shape, core material, agglomeration, and dissolution influence the effects of NPs. However, most studies evaluating NP-mediated reproductive toxicity have paid little or no attention to the influence of the physicochemical characteristics of NP on the observed effects. As accumulating evidence indicates that NP may reach the ovary to impair proper functions, this review summarizes the available data on NP accumulation in ovarian tissue, as well as data describing toxicity to ovarian functions, including sex steroid hormone production, follicular development, oocyte quality, and fertility. Due to their toxicological relevance, this review also describes the main physicochemical characteristics involved in NP toxicity and the importance of considering NP physicochemical characteristics as factors influencing the ovarian toxicity of NPs. Finally, this review summarizes the main mechanisms of toxicity described in ovarian cells.

Dual effects of JNK activation in blood-milk barrier damage induced by zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO-NPs) have been extensively applied in our daily life. Humans are at high risk of being exposed to ZnO-NPs, which induce potentially adverse health effects. Although a growing number of studies have investigated the toxic effects of ZnO-NPs, the available data concerning ZnO-NP interactions with the blood-milk barrier (BMB) remain highly limited. Herein, we systematically investigated the damage to BMB integrity induced by ZnO-NPs and the mechanisms involved. ZnO-NPs that were intravenously injected into lactating dams accumulated in the mammary gland and entered into the breast milk, inducing disruption to BMB integrity and changes in the tight junction (TJ) and adherens junction (AJ) components. Furthermore, using an in vitro BMB model composed of EpH4-Ev cells, we verified that ZnO-NP-triggered ROS generation and the activation of MKK4 and JNK are the main mechanism of cell-cell junction damage. More interestingly, JNK activation played different roles in inducing changes in the TJ and AJ complex, and these effects did not need to activate the downstream c-Jun. These data provide more information for understanding ZnO-NP interactions with the BMB and raise concern for the daily use and the intravenous use of ZnO-NPs by lactating mothers.

Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation

Polypropylene-based products are commonly used for food preparation and storage, but their capacity to release microplastics is poorly understood. We investigated the potential exposure of infants to microplastics from consuming formula prepared in polypropylene (PP) infant feeding bottles (IFBs). Here, we show that PP IFBs release microplastics with values as high as 16,200,000 particles per litre. Scenario studies showed that PP IFB sterilization and exposure to high-temperature water significantly increase microplastic release. A 21-d test of PP IFBs showed periodic fluctuations in microplastic release. To estimate the potential global exposure to infants up to 12 months old, we surveyed 48 regions, finding values ranging from 14,600-4,550,000 particles per capita per day, depending on the region. We demonstrate that infant exposure to microplastics is higher than was previously recognized due to the prevalence of PP-based products used in formula preparation and highlight an urgent need to assess whether exposure to microplastics at these levels poses a risk to infant health.

The inflammatory environment mediated by a high-fat diet inhibited the development of mammary glands and destroyed the tight junction in pregnant mice

Long-term intake of a high-fat diet seriously affects the health of pregnant women and leads to increased levels of inflammation in the mammary gland. Therefore, to further explore the effect of a high-fat diet on mammary gland development and the tight junction (TJ) during pregnancy, we placed mice into two groups: a high-fat diet group and a control group. We detected the expression of proteins related to fat synthesis in the mammary gland by western blotting. The results showed that a high-fat diet could lead to an increase in fat synthesis in the mammary gland. Then, the inflammatory levels and acinar cell morphology in the mammary gland were detected by ELISA and H&E staining. We also measured the levels of MAPK and NF-κB signal pathway-related proteins by western blotting. The results showed that a high-fat diet activated the MAPK and NF-κB signaling pathways and promoted the expression of inflammatory factors. Finally, the development of the mammary gland and the integrity of the TJ were determined by immunohistochemistry, immunofluorescence and western blotting. The results showed that a high-fat diet inhibited the development of the mammary gland and the expression of tight junction proteins (TJs). Our study showed that a high-fat diet could promote the expression of inflammatory factors by activating the MAPK and NF-κB signaling pathways and could reshape the microenvironment through extramammary inflammation. Finally, a high-fat diet inhibited the development of the mammary gland during pregnancy and destroyed the integrity of the TJ.

Transformation of Nanomaterials and Its Implications in Gut Nanotoxicology

Ingestion of engineered nanomaterials (ENMs) is inevitable due to their widespread utilization in the agrifood industry. Safety evaluation has become pivotal to identify the consequences on human health of exposure to these ingested ENMs. Much of the current understanding of nanotoxicology in the gastrointestinal tract (GIT) is derived from studies utilizing pristine ENMs. In reality, agrifood ENMs interact with their microenvironment, and undergo multiple physicochemical transformations, such as aggregation/agglomeration, dissolution, speciation change, and surface characteristics alteration, across their life cycle from synthesis to consumption. This work sieves out the implications of ENM transformations on their behavior, stability, and reactivity in food and product matrices and through the GIT, in relation to measured toxicological profiles. In particular, a strong emphasis is given to understand the mechanisms through which these transformations can affect ENM induced gut nanotoxicity.

Silver nanoparticles compromise the development of mouse pubertal mammary glands through disrupting internal estrogen signaling

Despite numerous studies on the environmental health and safety (EHS) of silver nanoparticles (AgNPs), most studies looked into their gross toxicities with rather limited understanding on their labyrinthine implicit effects on the target sites, such as the endocrine system. Burgeoning evidence documents the disrupting effects of AgNPs on endocrine functions; however, little research has been invested to recognize the potential impacts on the mammary gland, a susceptible estrogen-responsive organ. Under this setting, we here aimed to scrutinize AgNP-induced effects on the development of pubertal mammary glands at various concentrations that bear significant EHS relevance. We unearthed that AgNPs could accumulate in mouse mammary glands and result in a decrease in the percentage of ducts and terminal ducts in the adult mice after chronic exposure. Strikingly, smaller sized AgNPs showed greater capability to alter the pubertal mammary development than larger sized particles. Intriguingly, mechanistic investigation revealed that the reduction of epithelial proliferation in response to AgNPs was ascribed to reduced ERα expression, which, at least partially, accounted for diseased epithelial morphology in mammary glands. Meanwhile, the decline in fibrous collagen deposition around the epithelium was found to contribute to the compromised development of mammary glands under the exposure of AgNPs. Moreover, as an extension of the mechanism, AgNPs diminished serum levels of estradiol in exposed animals. Together, these results uncovered a novel toxicity feature of AgNPs: compromised development of mouse pubertal mammary glands through the endocrine-disrupting actions. This study would open a new avenue to unveil the EHS impacts of AgNPs.

Postnatal distribution of ZnO nanoparticles to the breast milk through oral route and their risk assessment for breastfed rat offsprings

Various studies in rodents have shown that nanoparticles are transferred to the breast milk. Under the present study, lactating Wistar rats were repetitively gavaged 5, 25, and 50 mg/kg bw of zinc oxide nanoparticles (ZnO-NPs) and 50 mg kg^-1 bw of bulk zinc oxide (bZnO) for 19 days after parturition. The results showed that ZnO-NPs were absorbed in the small intestine of dams and distributed to the liver. Furthermore, ZnO-NPs were distributed to the intestine and liver of rat pups through dam's milk. No significant change in body weight was observed in the dams treated with ZnO-NPs or bZnO and their offsprings as compared to the control group. The spleen weight significantly increased in the rat dams treated with 50 mg kg^-1 of ZnO-NPs. ZnO-NPs were mostly excreted through feces. The levels of liver cytochrome P450 reductase and serum total antioxidant capacity significantly decreased in the rat dams treated with ZnO-NPs (50 mg kg^-1) and their offsprings. The levels of serum cytokines (tumor necrosis factor-alpha and interleukin-1 beta) and liver injury marker enzymes (alanine aminotransferase and aspartate aminotransferase) significantly increased in the rat dams treated with ZnO-NPs (25 and 50 mg kg^-1) and their offsprings. The level of immunoglobulin A secretion in the intestinal fluid of rat dams and their offsprings is significantly increased by increasing the dose of ZnO-NPs. Histopathology of intestine and liver of offsprings whose rat dams were treated with ZnO-NPs (50 mg kg^-1) showed gross pathological changes. These results provide information for the safety evaluation of ZnO-NPs use during lactation. In conclusion, a dose-dependent postnatal transfer of ZnO-NPs is hazardous to the breastfed offsprings.

Crossing Biological Barriers by Engineered Nanoparticles

Engineered nanoparticles (ENPs) may cause toxicity if they cross various biological barriers and are accumulated in vital organs. Which factors affect barrier crossing efficiency of ENPs are crucial to understand. Here, we present strong data showing that various nanoparticles crossed biological barriers to enter vital animal organs and cause toxicity. We also point out that physicochemical properties of ENPs, modifications of ENPs in biofluid, and physiological and pathological conditions of the body all affect barrier crossing efficiency. We also summarized our limited understanding of the related mechanisms. On the basis of this summary, major research gaps and direction of further efforts are then discussed.

Translocation of transition metal oxide nanoparticles to breast milk and offspring: The necessity of bridging mother-offspring-integration toxicological assessments

Although infant nanomaterial exposure is a worldwide concern, breastfeeding transfer of transition metal-oxide nanoparticles to as well as their toxicity to offspring are still unclear. Breastfeeding transmits nutrition and immunity from mothers to their offspring; it also provides a portal for maternal toxins to enter offspring. Thus, a toxicology assessment of both mothers and their offspring should be established to monitor nanomaterial exposure during lactation. Here, we determined the effects of the exposure route on the biodistribution, biopersistence, and toxicology of nanoparticles (titanium dioxide, zinc oxide, and zirconium dioxide) in both mouse dams and their offspring. Oral and airway exposure routes were tested using gavage and intranasal administration, respectively. Biodistribution in the main organs (breast, liver, spleen, lung, kidney, intestine, and brain) and biopersistence in the blood and milk were determined using inductively coupled plasma mass spectrometry. Hematology and histomorphology analyses were performed to determine the toxicology of the nanoparticles. A reduced offspring body weight was found with the reduced nanoparticle size. Furthermore, both oral and airway exposure increased the nanoparticle concentrations in the main tissues and milk. More nanoparticles were transferred into maternal tissues and milk via airway exposure than via oral exposure. During the transfer of the metal from the exposed nanoparticles to milk, the immune cell pathway played a more important role in the airway route than in the oral exposure route. Finally, maternal exposure via both the oral and airway routes reduced the body weight and survival rate of their breastfeeding offspring, which could possibly be attributed to the toxicity of nanoparticles to blood cells and organs. In conclusion, maternal exposure to nanoparticles led to a reduced body weight and survival rate in breastfed offspring, and nanoparticle exposure via the airway route led to a higher immune response and tissue injury than that via the oral exposure route. This study suggests that the use of products containing metal nanoparticles in breastfeeding mothers and their offspring should be reconsidered to maintain a safe breastfeeding system.

Myricetin relieves LPS-induced mastitis by inhibiting inflammatory response and repairing the blood-milk barrier

Mastitis, an inflammation of mammary gland, is a serious disease that affects the health of dairy cows around the world. Myricetin, a flavonoid from Bayberry, has been reported to suppress various inflammatory response. The aim of this study was to evaluate the effect of myricetin on lipopolysaccharide (LPS)-induced in vivo and in vitro mastitis model and clarify the underlying mechanism. In vivo experiments, myricetin attenuated the severity of inflammatory lesion and neutrophil infiltration. Moreover, myricetin pretreatment induced a significant decrease in the activity of myeloperoxidase (MPO) and the production of TNF-α, IL-6, and IL-1β triggered by LPS. Myricetin pretreatment could also increase the integrity of the blood-milk barrier and upregulate the tight junction proteins in LPS-induced mice mastitis. In vitro, myricetin inhibited LPS-induced inflammatory response in mice mammary epithelial cells (mMECs). In the further mechanism studies, we found that the anti-inflammatory effect of myricetin was mediated by inhibiting LPS-induced phosphorylation of AKT, IKK-α, IκB-α, and P65 in vivo and in vitro. Collectively, these data suggested that myricetin effectively ameliorated the inflammatory response by inhibiting the AKT/IKK/NF-κB signaling pathway and repairing the integrity of blood-milk barrier in LPS-induced mice mastitis.

Preventative Effects of Vitamin E on Testicular Damage and Sperm Parameters in the First-Generation Mice Pups due to Pre- and Postnatal Mancozeb Exposure

The present study aimed to evaluate the effects of vitamin E on mancozeb-induced testis damage of the first-generation pups during intrauterine and lactating periods. Two groups of pregnant NMRI mice received 500 mg/kg mancozeb (MNZ) as MNZ group and 200 mg/kg vitamin E as MNZ+vit.E group before receiving MNZ. In addition, a vehicle and a control group were designed every other day in gestation and lactation periods. The male pups from each group were maintained until adulthood (8-10 W). The left testes and epididymides were removed following the sacrifice of the pups. Then, they were weighed, and sperm parameters including number, viability, motility, and morphology and testis structure were evaluated. A significant decrease occurred in sperm parameters of the mancozeb-treated pups compared to the control and vehicle groups. Treatment with vitamin E reversed the deleterious effects of MNZ to a nearly normal condition. Testis parameters including the weight, gonadosomatic index, seminiferous tubule diameters, and Johnsen's score, as well as the number of germ cells such as spermatogonia, spermatocyte, spermatid, and Sertoli, decreased significantly in the MNZ group, compared to the amount in the control and vehicle groups. Interestingly, the treatment with vitamin E was reversed in most of these parameters. Based on the results, the exposure of pups to mancozeb during pregnancy and lactating periods negatively affects the reproductive system of male pups. However, the coadministration of vitamin E could prevent the deleterious effects of mancozeb on sperm and testis parameters.

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.

Targeting gut microbiota as a possible therapy for mastitis

Mastitis, a disease that affects both dairy herds and humans, is recognized as the most common source of losses in the dairy industry. Antibiotics have been used for years as the primary treatment for mastitis. However, abuse of antibiotics has led to the emergence of resistant strains and the presence of drug residues and has increased the difficulty of curing this disease. In addition, antibiotics kill most of the microbes that are present in the digestive tract, leading to imbalances in the gut microbiome and destruction of the ecosystem that is normally present in the gut. Gut microbiota play an important role in the host's health and could be considered the "second brain" of the body. In recent years, the gut microbiota and their metabolites, including lipopolysaccharide (LPS) and short-chain fatty acids (SCFAs), have been shown to participate in the development of mastitis. LPS is the main component of the cell walls of gram-negative bacteria. Overproduction of rumen-derived LPS injures the rumen epithelium, resulting in the entry of LPS into the blood and damaged liver function; once in the blood, it circulates into the mammary gland, increasing blood-barrier permeability and leading to mammary gland inflammation. SCFAs, which are produced by gut microbiota as fermentation products, have a protective effect on mammary gland inflammatory responses and help maintain the function of the blood-milk barrier. Recently, increasing attention has been focused on the use of probiotics as a promising alternative for the treatment of mastitis. This review summarizes the effects of the gut microbiome and its metabolites on mastitis as well as the current of probiotics in mastitis. This work may provide a valuable theoretical foundation for the development of fresh ideas for the prevention and treatment of mastitis.

Why are nanoparticles trapped at cell junctions when the cell density is high?

Research on nanoparticle (NP)-cell interactions has been extensively carried out in dilute cell cultures, where NPs are heavily internalized by cells. However, it is not known whether the findings from cell culture studies are still true in tissues where cells are tightly packed. Here, we show experimentally and theoretically that when cells are tightly packed, cellular uptake is strongly hindered. When simultaneously encountering two adjacent cells as is often the case in tissues, adhesion, bending and protrusion of at least two membranes from these cells generate complicated energy contributions that cause trapping of NPs at cell junctions with impeded uptake.

Curcumin induces apoptosis and inhibits angiogenesis in murine malignant mesothelioma

Malignant pleural mesothelioma (MPM) is a rare form of cancer that is associated with asbestos exposure. Unfortunately, current therapies have limited efficacy. Previous studies have indicated that curcumin exerts antiproliferative and antitumor effects, and has low toxicity. The present study aimed to evaluate the anticancer effects of curcumin on the RN5 MPM cell line. The inhibitory effects of curcumin on cell viability were determined using the sulforhodamine B assay. In addition, cell cycle progression was analyzed by propidium iodide (PI) staining and flow cytometry, and curcumin‑induced apoptosis was measured by Annexin V/PI double staining. The translocation of apoptosis-inducing factor (AIF) was assessed by western blotting and immunofluorescence, and the expression levels of the phosphoinositide 3-kinase (PI3K)-AKT serine/threonine kinase (Akt)‑mammalian target of rapamycin (mTOR) signaling pathway proteins and mitochondria-associated proteins were evaluated by western blotting. In vivo antitumor effects were evaluated in a subcutaneous murine model. Briefly, tumors were harvested from the mice, and immunohistochemistry was conducted to evaluate cell proliferation, apoptosis and angiogenesis. The results indicated that curcumin inhibited RN5 cell viability and induced apoptotic cell death. In addition the findings suggested that curcumin-induced cell apoptosis occurred via the mitochondrial pathway, and caspase‑independent and AIF-dependent pathways. Further analysis revealed that curcumin may act as a PI3K-Akt-mTOR signaling pathway inhibitor by downregulating PI3K, p-Akt, p-mTOR and p-p70 ribosomal protein S6 kinase. Furthermore, curcumin inhibited tumor angiogenesis in vivo. In conclusion, curcumin may be potent enough to be developed as a novel therapeutic agent for the treatment of MPM.

Engineered nanomaterials and human health: Part 2. Applications and nanotoxicology (IUPAC Technical Report)

Research on engineered nanomaterials (ENM) has progressed rapidly from the very early stages of studying their unique, size-dependent physicochemical properties and commercial exploration to the development of products that influence our everyday lives. We have previously reviewed various methods for synthesis, surface functionalization, and analytical characterization of ENM in a publication titled ‘Engineered Nanomaterials: Preparation, Functionalization and Characterization’. In this second, inter-linked document, we first provide an overview of important applications of ENM in products relevant to human healthcare and consumer goods, such as food, textiles, and cosmetics. We then highlight the challenges for the design and development of new ENM for bio-applications, particularly in the rapidly developing nanomedicine sector. The second part of this document is dedicated to nanotoxicology studies of ENM in consumer products. We describe the various biological targets where toxicity may occur, summarize the four nanotoxicology principles, and discuss the need for careful consideration of the biodistribution, degradation, and elimination routes of nanosized materials before they can be safely used. Finally, we review expert opinions on the risk, regulation, and ethical aspects of using engineered nanomaterials in applications that may have direct or indirect impact on human health or our environment.

Quantum dots cause acute systemic toxicity in lactating rats and growth restriction of offspring

The in vivo toxicity of QDs in animals has been broadly studied; however, their reproductive toxicity towards lactating rodents is currently unknown. This study therefore aims to assess the potential toxicity against dams and offspring after postnatal QD exposure at two doses (5 and 1 nmol per rat) and unravel whether QDs can translocate to pups via breastfeeding. The dose-dependent systemic toxicity of QDs in dams was observed by examining the body weight, hematology, biochemistry, histopathological changes, and sex hormone levels. It was found that the QDs primarily accumulated in the liver and spleen of dams at 1 day post injection (dpi), but the highest concentrations were found in the kidneys at 18 dpi. A few QDs were detected in breast milk and stomach and intestine of pups; this suggested that the QDs were transmitted to breast milk via blood circulation and then transferred to pups via breastfeeding. High-dose QDs induced severe growth inhibition and a 71.08% offspring mortality, while pups showed growth restriction within 90 dpi in the low-dose group. Moreover, the hematology, biochemistry, and histology results showed limited chronic toxicity against offspring in the long term. This study provides a theoretical foundation for the exposure assessment of nanomaterials in lactating animals and for the advancement of QDs in the biomedical field.

Phytoestrogens Weaken the Blood-Milk Barrier in Lactating Mammary Epithelial Cells by Affecting Tight Junctions and Cell Viability

During lactation, mammary epithelial cells (MECs) form the blood-milk barrier by less-permeable tight junctions (TJs) to prevent the leakage of milk components. Phytoestrogens affect the proliferation, differentiation, and apoptosis of MECs. However, it remains unclear whether phytoestrogens are involved in the blood-milk barrier. Therefore, we investigated the influence of phytoestrogens (coumestrol, genistein, and daidzein) by using an in vitro mouse-MEC-culture model. The results showed that coumestrol and genistein changed the expression of TJ proteins (claudins-3 and -4 and occludin), weakened barrier function, and reduced β-casein production. Daidzein also weakened barrier function without inhibiting β-casein production. Additionally, coumestrol and genistein induced apoptosis in MECs. These results indicate that phytoestrogens weaken the blood-milk barrier by directly affecting TJs and the cellular viability of lactating MECs in different ways.

Propionate Protects against Lipopolysaccharide-Induced Mastitis in Mice by Restoring Blood-Milk Barrier Disruption and Suppressing Inflammatory Response

Mastitis, an inflammation of the mammary glands, is a major disease affecting dairy animal worldwide. Propionate is one of the main short-chain fatty acid that can exert multiple effects on the inflammatory process. The purpose of this study is to investigate the mechanisms underlying the protective effects of sodium propionate against lipopolysaccharide (LPS)-induced mastitis model in mice. The data mainly confirm that inflammation and blood–milk barrier breakdown contribute to progression of the disease in this model. In mice with LPS, sodium propionate attenuates the LPS-induced histopathological changes, inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) production, myeloperoxidase activity in mammary tissues. Given their importance in the blood–milk barrier, tight junction proteins occludin and claudin-3 are further investigated. Our results show that sodium propionate strikingly increases the expressions of occludin and claudin-3 and reduces the blood–milk barrier permeability in this model. Furthermore, in LPS-stimulated mouse mammary epithelial cells (mMECs), LPS increased the expressions of phosphorylated (p)-p65, p-IκB proteins, which is attenuated by sodium propionate. Finally, we examine the possibility that propionate acts as a histone deacetylase (HDAC) inhibitor, the results show that both sodium propionate and trichostatin A increase the level of histone H3 acetylation and inhibit the increased production of TNF-α, IL-6, and IL-1β in LPS-stimulated mMECs. These data suggest that sodium propionate protects against LPS-induced mastitis mainly by restoring blood–milk barrier disruption and suppressing inflammation via NF-κB signaling pathway and HDAC inhibition.

Butyrate protects against disruption of the blood-milk barrier and moderates inflammatory responses in a model of mastitis induced by lipopolysaccharide

BACKGROUND AND PURPOSE

Short-chain fatty acids are fermentation end products produced by gut bacteria, which have been shown to ameliorate inflammatory bowel diseases and allergic asthma. However, the mechanism involved remains largely unknown. Here, we investigate the protective effects and mechanisms of sodium butyrate (SB) on LPS-induced mastitis model.

EXPERIMENTAL APPROACH

Effects of increasing doses of SB on blood-milk barrier function and inflammation are studied in BALB/c mice with LPS-induced mastitis. The underlying mechanisms of anti-inflammatory effects of SB were further investigated in LPS-stimulated mouse mammary epithelial cells (mMECs).

KEY RESULTS

The results show that SB decreased LPS-induced disruption in mammary tissues, infiltration of inflammatory cells and the levels of TNF-α, IL-6 and IL-1β. SB up-regulated the tight junction proteins occludin and claudin-3 and reduced blood-milk barrier permeability in LPS-induced mastitis. Studies in vitro revealed that SB inhibited LPS-induced inflammatory response by inhibition of the NF-κB signalling pathway and histone deacetylases in LPS-stimulated mMECs.

CONCLUSIONS AND IMPLICATIONS

In our model, SB protected against LPS-induced mastitis by preserving blood-milk barrier function and depressing pro-inflammatory responses, suggesting the potential use of SB as a prophylactic agent to protect blood-milk barrier function in mastitis.

Nano-safety Research: Examining the Associations among the Biological Effects of Nanoparticles and Their Physicochemical Properties and Kinetics

In the past decade, nanotechnology has advanced rapidly, and many products containing nanoparticles are now an important part of our daily lives. Despite our increasing exposure to nanoparticles, however, information regarding the absorption, distribution, metabolism, excretion, and toxicity of nanoparticles remains limited. In this review, we introduce our group's ongoing research into the biological effects and toxicities of nanoparticles, which we broadly refer to as "nano-safety research." In addition to determining the biological effects of nanoparticles and elucidating the underlying mechanisms of those effects, we are also exploring the associations among the physicochemical properties and kinetics of nanoparticles. Furthermore, we are currently developing a battery of biomarkers that we hope will be used to predict the biological effects of nanoparticles during the early stages of development. Our research provides valuable basic information on the safety of nanoparticles. We hope that this information will be used for the development of better assessments of nanoparticles safety and for the creation of more appropriate regulations to ensure not only the safety but also the sustainability of nanotechnology.

Susceptibility of Overweight Mice to Liver Injury as a Result of the ZnO Nanoparticle-Enhanced Liver Deposition of Pb2

The prevalence of the applications of nanomaterials in consumer products and water treatment facilities increases the chance that humans will be exposed to both nanoparticles and environmental pollutants such as heavy metals. Co-exposure to nanoparticles and heavy metals may adversely affect human health, especially in susceptible populations such as overweight subjects. To evaluate the impact of such co-exposures, we orally administered zinc oxide nanoparticles (ZNPs; 14 or 58 nm) and/or Pb(Ac)₂ at tolerable doses to both healthy overweight and healthy normal weight mice. The ZNPs enhanced the deposition of Pb in all major organs in the overweight mice compared with that in the normal mice. As a result, higher levels of hepatic reactive oxygen species, pro-inflammatory cytokines, and liver injury were observed in the overweight mice but not in the normal weight mice. Our findings underscore a potentially enhanced risk of nanoparticle/heavy metal co-exposure in the susceptible overweight population.

Distribution of Silver Nanoparticles to Breast Milk and Their Biological Effects on Breast-Fed Offspring Mice

Recent rodent studies have shown that nanoparticles are distributed to breast milk, and more-detailed safety information regarding nanoparticle consumption by lactating mothers is required. Here, we used mice to investigate the safety of nanoparticle use during lactation. When Ag and Au nanoparticles were intravenously administered to lactating mice, the nanoparticles were distributed to breast milk without producing apparent damage to the mammary gland, and the amount of Ag nanoparticles distributed to breast milk increased with decreasing particle size. Orally administered Ag nanoparticles were also distributed to breast milk and subsequently to the brains of breast-fed pups. Ten-nanometer Ag nanoparticles were retained longer in the pups' brains than in their livers and lungs. Nevertheless, no significant behavioral changes were observed in offspring breast-fed by dams that had received orally administered 10 nm Ag nanoparticles. These data provide basic information for evaluating the safety of nanoparticle use during lactation.

Effect of bisphenol A on morphology, apoptosis and proliferation in the resting mammary gland of the adult albino rat

Bisphenol A (BPA) is a synthetic oestrogen that is extensively used in a wide range of daily used plastic products. This makes it one of the environmental chemicals that may have impact on human health. Due to its oestrogenic effect, BPA might affect the mammary gland. This study aimed to investigate the influence of BPA on the histological structure of the mammary gland of the adult female albino rat and its effect on epithelial cell proliferation and apoptosis status, in addition to its possible modulating effect on estrogen receptor expression. Thirty female adult albino rats were divided into control and experimental groups. The rats in the experimental group were gavaged with 5 mg/kg BPA daily for 8 weeks. The mammary glands were dissected and processed for histological and immunohistochemical stains for Ki-67, activated caspase-3 and estrogen receptor alpha (ER-α). BPA induced an increase in the number and size of the acini and ducts in the mammary gland of treated rats with hyperplasia of their lining epithelial cells. The collagen fibre content was significantly increased in the connective tissue stroma separating the ducts. Immunohistochemical results showed a significant increase in Ki-67 and caspase-3, but a non-significant increase in ER-α expression. Bisphenol A induced structural changes and affected the proliferation rate of mammary glands, so it might be one of the predisposing factors for breast cancer.

Safety Profile of TiO₂-Based Photocatalytic Nanofabrics for Indoor Formaldehyde Degradation

Anatase TiO₂ nanoparticles (TNPs) are synthesized using the sol-gel method and loaded onto the surface of polyester-cotton (65/35) fabrics. The nanofabrics degrade formaldehyde at an efficiency of 77% in eight hours with visible light irradiation or 97% with UV light. The loaded TNPs display very little release from nanofabrics (~0.0%) during a standard fastness to rubbing test. Assuming TNPs may fall off nanofabrics during their life cycles, we also examine the possible toxicity of TNPs to human cells. We found that up to a concentration of 220 μg/mL, they do not affect viability of human acute monocytic leukemia cell line THP-1 macrophages and human liver and kidney cells.