Effect of ultrafine carbon black particles on lipoteichoic acid-induced early pulmonary inflammation in BALB/c mice

TLR4, MyD88, and TNF-α Expression in the Lungs of Akkaraman and Romanov Lambs in Response to LPS and LTA

Toll-like receptors are involved in the recognition of bacterial toxins, which cause infection in the respiratory system. This study aimed to evaluate microanatomical and histological alterations in the lungs of 24 healthy Akkaraman and Romanov lambs after the administration of lipoteichoic acid (LTA), lipopolysaccharide (LPS), and LTA + LPS and investigate the gene, protein, and immune expression levels of TLR4, MyD88, and TNF-α molecules, known to have immune functions. Microanatomical examinations showed thickened peribronchial and alveolar walls in the lungs of groups LTA, LPS, and LTA + LPS of both breeds due to immune cell infiltration. TLR4, MyD88, and TNF-α immunoexpressions were positive to varying degrees in the cytoplasm and nucleus of the bronchial and bronchiolar luminal epithelial cells, alveolar epithelial cells, and alveolar macrophages. TLR4 and TNF-α protein expressions were statistically different in the LPS-treated Romanov lambs, compared to the other groups. Among the Akkaraman lambs, TLR4 gene expression was significantly higher in group LPS, and among the Romanov lambs, TLR4, MyD88, and TNF-α gene expressions were significantly higher in group LTA + LPS. Therefore, TLR4, MyD88, and TNF-α molecules, involved in the immune response, were found to be expressed at different levels against LTA and LPS in the lungs of two different sheep breeds.

Autophagy changes in lung tissues of mice at 30 days after carbon black-metal ion co-exposure

OBJECTIVES

Accumulating studies have investigated the PM2.5-induced pulmonary toxicity, while gaps still remain in understanding its toxic mechanism. Due to its high specific surface area and adsorption capacity similar to nanoparticles, PM2.5 acts as a significant carrier of metals in air and then leads to altered toxic effects. In this study, we aimed to use CBs and Ni as model materials to investigate the autophagy changes and pulmonary toxic effects at 30 days following intratracheal instillation of CBs-Ni mixture.

MATERIALS AND METHODS

Groups of mice were instilled with 100 µL normal saline (NS), 20 µg CBs, and 4 µg Ni or CBs-Ni mixture, respectively. At 7 and 30 days post-instillation, all the mice were weighed and then sacrificed. The evaluation system was composed of the following: (a) autophagy and lysosomal function assessment, (b) trace element biodistribution observation in lungs, (c) pulmonary lavage biomedical analysis, (d) lung histopathological evaluation, (e) coefficient analysis of major organs and (f) CBs-Ni interaction and cell proliferation assessment.

RESULTS

We found that after CBs-Ni co-exposure, no obvious autophagy and lysosomal dysfunction or pulmonary toxicity was detected, along with complete clearance of Ni from lung tissues as well as recovery of biochemical indexes to normal range.

CONCLUSIONS

We conclude that the damaged autophagy and lysosomal function, as well as physiological function, was repaired at 30 days after exposure of CBs-Ni. Our findings provide a new idea for scientific assessment of the impact of fine particles on environment and human health, and useful information for the comprehensive treatment of air pollution.

A study of the correlation between ultrafine particle emissions in motorcycle smoke and mice erythrocyte damages

Sharply increasing of motor vehicles every year contributes to amounts of ultrafine particles (UFPs) in the air. Besides, the existence of UFPs in the blood may cause erythrocyte damages that subject to shape deformation. This study was aimed to investigate the influence of UFPs in the motorcycle smoke exposed to mice in different concentrations to the erythrocyte damages. The experiments were conducted by injecting the motorcycle smoke with the varied amounts in an experimental chamber (dimension of 30×20×20cm³) where the mice were put in advance for exposuring twice a day (100s). Total numbers of UFPs in the smoke were calculated by measuring the total concentrations multiplied by the smoke debit. They were measured using a TSI 8525 P-Trak UPC. The effects of the smoke exposures in the mice's erythrocytes related to the UFPs in the smoke were observed by a binocular CX-31 Computer Microscope after the 2nd, 4th, 6th, 8th, and 10th exposure days. The erythrocyte damages were calculated from the total abnormal erythrocytes divided by the total erythrocytes. Our results showed that more UFPs exposed to mice resulted in more the erythrocytes damages. Longer exposures caused more damages of the mice erythrocytes. This study found significant correlations between the numbers of UFPs exposed to mice and the erythrocyte damages. Our finding gives important evidence that motorcycle emissions especially UFPs affect on health.

Zinc oxide nanoparticles induce migration and adhesion of monocytes to endothelial cells and accelerate foam cell formation

Metal oxide nanoparticles are widely used in industry, cosmetics, and biomedicine. However, the effects of exposure to these nanoparticles on the cardiovascular system remain unknown. The present study investigated the effects of nanosized TiO2 and ZnO particles on the migration and adhesion of monocytes, which are essential processes in atherosclerogenesis, using an in vitro set-up of human umbilical vein endothelial cells (HUVECs) and human monocytic leukemia cells (THP-1). We also examined the effects of exposure to nanosized metal oxide particles on macrophage cholesterol uptake and foam cell formation. The 16-hour exposure to ZnO particles increased the level of monocyte chemotactic protein-1 (MCP-1) and induced the migration of THP-1 monocyte mediated by increased MCP-1. Exposure to ZnO particles also induced adhesion of THP-1 cells to HUVECs. Moreover, exposure to ZnO particles, but not TiO2 particles, upregulated the expression of membrane scavenger receptors of modified LDL and increased cholesterol uptake in THP-1 monocytes/macrophages. In the present study, we found that exposure to ZnO particles increased macrophage cholesterol uptake, which was mediated by an upregulation of membrane scavenger receptors of modified LDL. These results suggest that nanosized ZnO particles could potentially enhance atherosclerogenesis and accelerate foam cell formation.

Dispersion method for safety research on manufactured nanomaterials

Nanomaterials tend to agglomerate in aqueous media, resulting in inaccurate safety assessment of the biological response to these substances. The present study searched for suitable dispersion methods for the preparation of nanomaterial suspensions. Titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles were dispersed in a biocompatible dispersion medium by direct probe-type sonicator and indirect cup-type sonicator. Size characterization was completed using dynamic light scattering and transmission electron microscopy. A series of dispersion time and output power, as well as two different particle concentrations were tested. Microscopic contamination of metal titanium that broke away from the tip of the probe into the suspension was found. Size of agglomerated nanoparticles decreased with increase in sonication time or output power. Particle concentration did not show obvious effect on size distribution of TiO2 nanoparticles, while significant reduction of secondary diameter of ZnO was observed at higher concentration. A practicable protocol was then adopted and sizes of well-dispersed nanoparticles increased by less than 10% at 7 d after sonication. Multi-walled carbon nanotubes were also well dispersed by the same protocol. The cup-type sonicator might be a useful alternative to the traditional bath-type sonicator or probe-type sonicator based on its effective energy delivery and assurance of suspension purity.

Differences in lipopolysaccharide- and lipoteichoic acid-induced cytokine/chemokine expression

Purpose

To investigate differences in cytokine/chemokine release in response to lipoteichoic acid (LTA) or lipopolysaccharide (LPS) and contributing cellular mechanisms, in order to improve understanding of the pathogenesis of sepsis.

Methods

Levels of cytokines/chemokines were measured in plasma and peritoneal lavage fluid of 10-week-old male mice (C57/B16) following intraperitoneal injection of LTA or LPS (250 µg), and in supernatants of murine J774.2 cells, immortalised blood monocytes, or isolated human monocytes treated with LTA or LPS (0–10 µg/ml). The role of cytokine/chemokine messenger RNA (mRNA) stability versus nuclear factor-kappaB (NF-κB) and activator protein-1 (AP-1) in mediating cytokine/chemokine release in J774 cells was also assessed.

Results

In mice, plasma levels of keratinocyte-derived chemokine (KC), macrophage inflammatory protein (MIP)-2, interleukin (IL)-10, interferon (IFN)-γ and tumour necrosis factor-alpha (TNF-α) and peritoneal lavage fluid levels of KC, MIP-2 and TNF-α increased significantly 1 h after LPS. Only KC and MIP-2 levels increased 1 h after LTA. LPS-treated (10 μg/ml) J774 cells released MIP-2, IL-10, IFN-γ and TNF-α but not KC (24 h), whereas cells treated with 10 μg/ml LTA released only MIP-2. LPS-stimulated human monocytes released IL-10 and IL-8 (24 h); by contrast, LTA-treated cells released only IL-8. LPS and LTA activated NF-κB and AP-1 in J774 cells. The protein synthesis inhibitor cycloheximide abolished LPS-induced IL-10 mRNA expression and increased LTA- and LPS-induced mRNA for MIP-2 in J774 cells.

Conclusion

LTA and LPS, at clinically relevant concentrations, induced differential cytokine/chemokine release in vitro and in vivo, via effects distal to activation of NF-κB/AP-1 that might include chromatin remodelling or mRNA stability.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-011-2444-5) contains supplementary material, which is available to authorized users.

Systemically administered ligands of Toll-like receptor 2, -4, and -9 induce distinct inflammatory responses in the murine lung

Objective. To determine whether systemically administered TLR ligands differentially modulate pulmonary inflammation. Methods. Equipotent doses of LPS (20 mg/kg), CpG-ODN (1668-thioat 1 nmol/g), or LTA (15 mg/kg) were determined via TNF activity assay. C57BL/6 mice were challenged intraperitoneally. Pulmonary NFκB activation (2 h) and gene expression/activity of key inflammatory mediators (4 h) were monitored. Results. All TLR ligands induced NFκB. LPS increased the expression of TLR2, 6, and the cytokines IL-1αβ, TNF-α, IL-6, and IL-12p35/p40, CpG-ODN raised TLR6, TNF-α, and IL12p40. LTA had no effect. Additionally, LPS increased the chemokines MIP-1α/β, MIP-2, TCA-3, eotaxin, and IP-10, while CpG-ODN and LTA did not. Myeloperoxidase activity was highest after LPS stimulation. MMP1, 3, 8, and 9 were upregulated by LPS, MMP2, 8 by CpG-ODN and MMP2 and 9 by LTA. TIMPs were induced only by LPS. MMP-2/-9 induction correlated with their zymographic activities. Conclusion. Pulmonary susceptibility to systemic inflammation was highest after LPS, intermediate after CpG-ODN, and lowest after LTA challenge.

Review: Do engineered nanoparticles pose a significant threat to the aquatic environment?

Nanotechnology is a rapidly growing industry of global economic importance, exploiting the novel characteristics of materials manufactured at the nanoscale. The properties of engineered nanoparticles (ENPs) that make them useful in a wide range of industrial applications, however, have led to concerns regarding their potential impact on human and environmental health. The aquatic environment is particularly at risk of exposure to ENPs, as it acts as a sink for most environmental contaminants. This paper critically evaluates what is currently known about sources and discharge of ENPs to the aquatic environment and how the physicochemical characteristics of ENPs affect their fate and behaviour and thus availability for uptake into aquatic organisms, and assesses reported toxicological effects. Having reviewed the ecotoxicological information, the conclusion is that whilst there are data indicating some nanoparticles have the potential to induce harm in exposed aquatic organisms, there is insufficient evidence for harm, for known/modelled environmental concentrations for almost all ENPs considered. This conclusion, however, must be balanced by the fact that there are significant gaps in our understanding on the fate and behaviour of ENPs in the aquatic environment. Greater confidence in the assessments on ENP impacts in aquatic systems to enable effective comparisons across studies urgently requires more standardised approaches for ENP hazard identification, and critically, more thorough characterisations on the exposed particles. There is also an urgent need for the advancement of tools and techniques that can accurately quantify and visualise uptake of nanoparticles into biological tissues.

Effects of ultrafine particles-induced oxidative stress on Clara cells in allergic lung inflammation

Background

Clara cell protein (CC16), the main secretory product of bronchiolar Clara cells, plays an important protective role in the respiratory tract against oxidative stress and inflammation. The purpose of the study was to investigate the role of elemental carbon ultrafine particles (EC-UFP)-induced oxidative stress on Clara cells and CC16 in a mouse model of allergic lung inflammation.

Methods

Ovalbumin (OVA)-sensitized mice were exposed to EC-UFP (507 μg/m³ for 24 h) or filtered air immediately prior to allergen challenge and systemically treated with N-acetylcysteine (NAC) or vehicle prior and during EC-UFP inhalation. CC16 was measured up to one week after allergen challenge in bronchoalveolar lavage fluid (BALF) and in serum. The relative expression of CC16 and TNF-α mRNA were measured in lung homogenates. A morphometrical analysis of mucus hypersecretion and electron microscopy served to investigate goblet cell metaplasia and Clara cell morphological alterations.

Results

In non sensitized mice EC-UFP inhalation caused alterations in CC16 concentration, both at protein and mRNA level, and induced Clara cell hyperplasia. In sensitized mice, inhalation of EC-UFP prior to OVA challenge caused most significant alterations of BALF and serum CC16 concentration, BALF total protein and TNF-α relative expression compared to relevant controls; their Clara cells displayed the strongest morphological alterations and strongest goblet cell metaplasia occurred in the small airways. NAC strongly reduced both functional and morphological alterations of Clara cells.

Conclusion

Our findings demonstrate that oxidative stress plays an important role in EC-UFP-induced augmentation of functional and morphological alterations of Clara cells in allergic lung inflammation.

Synergistic genotoxicity caused by low concentration of titanium dioxide nanoparticles and p,p'-DDT in human hepatocytes

The use of titanium dioxide nanoparticles (nano-TiO(2)) for the degradation of dichlorodiphenyltrichloroethane (p,p'-DDT) increases the risk of exposure to trace nano-TiO(2) and p,p'-DDT mixtures. The interaction of p,p'-DDT and nano-TiO(2) at low concentrations may alter toxic response relative to nano-TiO(2) or p,p'-DDT alone. In this work, the combined genotoxicity of trace nano-TiO(2) and p,p'-DDT on human embryo L-02 hepatocytes without photoactivation was studied. Nano-TiO(2) (0.1 g/L) was mixed with 0.01-1 mmol/L p,p'-DDT to determine adsorption isotherms. L-02 cells were exposed to different levels of p,p'-DDT (0, 0.001, 0.01, and 0.1 mumol/L) and nano-TiO(2) (0, 0.01, 0.1, and 1 microg/mL) respectively. The adsorption of p,p'-DDT by nano-TiO(2) was approximately 0.3 mmol/g. Cell viability, apoptosis, and DNA double strand breaks were similar among all test groups. Nano-TiO(2) alone (0.01-1 microg/mL) increased the levels of oxidative stress and oxidative DNA adducts (8-OHdG), but it did not induce DNA breaks or chromosome damage. Addition of trace nano-TiO(2) with trace p,p'-DDT synergistically enhanced genotoxicity via increasing oxidative stress, oxidative DNA adducts, DNA breaks, and chromosome damage in L-02 cells. Low concentrations of nano-TiO(2) and p,p'-DDT increased oxidativestress by reactive oxygen species (ROS) formation and lipid oxidation. Oxidative stress is a major pathway for DNA and chromosome damage. Dose-dependent synergistic genotoxicity induced by combined exposure of trace p,p'-DDT and nano-TiO(2) suggests a potential environmental risk of nano-TiO(2) assisted photocatalysis.

Extracellular glutamate level and NMDA receptor subunit expression in mouse olfactory bulb following nanoparticle-rich diesel exhaust exposure

In this present study, we aimed to investigate the extracellular glutamate level and memory function-related gene expression in the mouse olfactory bulb after exposure of the animals to nanoparticle-rich diesel exhaust (NRDE) with or without bacterial cell wall component. Lipoteichoic acid (LTA), a cell wall component derived from Staphylococcus aureus, was used to induce systemic inflammation. Male BALB/c mice were exposed to clean air (particle concentration, 4.58 microg/m(3)) or NRDE (148.86 microg/m(3)) 5 h per day on 5 consecutive days of the week for 4 wk with or without weekly intraperitoneal injection of LTA. We examined the extracellular glutamate levels in the olfactory bulb using in vivo microdialysis and high-performance liquid chromatography assay. Then, we collected the olfactory bulb to examine the expression of N-methyl-D-aspartate (NMDA) receptor subunits (NR1, NR2A, and NR2B) and calcium/calmodulin-dependent protein kinase (CaMK) IV and cyclic AMP response element binding protein (CREB)-1 using real-time reverse-transcription polymerase chain reaction (RT-PCR). NRDE and/or LTA caused significantly increased extracellular glutamate levels in the olfactory bulb of mice. Moreover, the exposure of mice to NRDE upregulates NR1, NR2A, NR2B, and CaMKIV mRNAs in the olfactory bulb, while LTA upregulates only NR2B and CREB1 mRNAs. These findings suggest that NRDE and LTA cause glutamate-induced neurotoxicity separately and accompanied by changes in the expression of NMDA receptor subunits and related kinase and transcription factor in the mouse olfactory bulb. This is the first study to show the correlation between glutamate toxicity and memory function-related gene expressions in the mouse olfactory bulb following exposure to NRDE.

Intrapulmonary delivery of ethyl pyruvate attenuates lipopolysaccharide- and lipoteichoic acid-induced lung inflammation in vivo

Ethyl pyruvate (EP) is a stable pyruvate derivative that has been shown to exert anti-inflammatory effects in various models of systemic inflammation including endotoxemia. We here sought to determine the local effects of EP, after intrapulmonary delivery, in models of lung inflammation induced by instillation via the airways of either lipopolysaccharide (LPS, a constituent of the gram-negative bacterial cell wall) or lipoteichoic acid (LTA, a component of the gram-positive bacterial cell wall). For this, we first established that EP dose dependently reduced the responsiveness of mouse MH-S alveolar macrophages and mouse MLE-15 and MLE-12 respiratory epithelial cells to stimulation with LPS or LTA in vitro. We then showed that intranasal administration of EP dose dependently inhibited tumor necrosis factor alpha release in bronchoalveolar lavage fluid of mice challenged with either LPS or LTA via the airways. Moreover, EP reduced the recruitment of neutrophils into the bronchoalveolar space after either LPS or LTA administration. These data suggest that intrapulmonary delivery of EP diminishes lung inflammation induced by LPS or LTA, at least in part by targeting alveolar macrophages and respiratory epithelial cells.

Changes in neurotransmitter levels and proinflammatory cytokine mRNA expressions in the mice olfactory bulb following nanoparticle exposure

Recently, there have been increasing reports that nano-sized component of particulate matter can reach the brain and may be associated with neurodegenerative diseases. Previously, our laboratory has studied the effect of intranasal instillation of nano-sized carbon black (CB) (14 nm and 95 nm) on brain cytokine and chemokine mRNA expressions and found that 14-nm CB increased IL-1 beta, TNF-alpha, CCL2 and CCL3 mRNA expressions in the olfactory bulb, not in the hippocampus of mice. To investigate the effect of a single administration of nanoparticles on neurotransmitters and proinflammatory cytokines in a mouse olfactory bulb, we performed in vivo microdialysis and real-time PCR methods. Ten-week-old male BALB/c mice were implanted with guide cannula in the right olfactory bulb and, 1 week later, were instilled vehicle or CB (14 nm, 250 microg) intranasally. Six hours after the nanoparticle instillation, the mice were intraperitoneally injected with normal saline or 50 mug of bacteria cell wall component lipoteichoic acid (LTA), which may potentiate CB-induced neurologic effect. Extracellular glutamate and glycine levels were significantly increased in the olfactory bulb of CB-instilled mice when compared with vehicle-instilled control mice. Moreover, we found that LTA further increased glutamate and glycine levels. However, no alteration of taurine and GABA levels was observed in the olfactory bulb of the same mice. We also detected immunological changes in the olfactory bulb 11 h after vehicle or CB instillation and found that IL-1 beta mRNA expression was significantly increased in CB- and LTA-treated mice when compared with control group. However, TNF-alpha mRNA expression was increased significantly in CB- and saline-treated mice when compared with control group. These findings suggest that nanoparticle CB may modulate the extracellular amino acid neurotransmitter levels and proinflammatory cytokine IL-1 beta mRNA expressions synergistically with LTA in the mice olfactory bulb.