Effects of styrene monomer on a mouse model of atopic dermatitis.

Aim: Styrene monomer (SM) is a basic chemical used as a raw material for polystyrene and unsaturated polyester resins and in the production of synthetic resins, synthetic rubbers, paints, and adhesives. To date, it is unclear whether SM is associated with the aggravation of atopic dermatitis. The aim was to investigate the effects of SM on atopic dermatitis-like skin lesions induced by mite allergen in NC/Nga mice.Methods: Male mice were injected intradermally with mite allergen on their right ears. In the presence of an allergen, SM (3.5 or 350 µg/animal/week) was administered by intraperitoneal injection. We evaluated clinical scores, ear thickening, histologic findings, and the protein expressions of cytokines and chemokines.Results: Macroscopic and microscopic examinations demonstrated that exposure to SM at a dose of 3.5 µg caused an exacerbation of atopic dermatitis-like skin lesions related to mite allergen. These changes were consistent with the level of histamine in the ear tissue as an overall trend. In contrast, 350-µg SM did not show significant enhancement effects.Conclusion: These results indicate that SM exacerbated atopic dermatitis-like skin lesions at hundred-fold lower levels than the level that causes no observed adverse effects as determined by histologic changes in rodent livers. SM could be at least partly responsible for the recent increase in atopic dermatitis.Impact statementStyrene monomer (SM) is classified as an International Agency for Research on Cancer group 2B carcinogen and includes neurotoxicity and respiratory disorders. However, the effects of SM as a chemical substance on existing allergic pathophysiology have not been elucidated yet. This study demonstrated that SM exacerbated murine atopic dermatitis-like skin lesions at hundred-fold lower levels than the level that causes no observed adverse effects as determined by histologic changes in rodent livers, which was concomitant with the local level of histamine. These data hasten a need for comprehensive research to clarify the chemical pollutants' effects of doses much lower than NOAEL on vulnerable pathophysiologies such as allergy/atopy.

Toxicological effects of Tris (1,3-dichloro-2-propyl) phosphate exposure in adult male rats differ depending on the history of exposure in the neonatal period.

There is increasing concern about multiple high concentration exposure to toxins in disaster and emergency situations. However, conventional toxicology testing methods may not adequately address these situations. Thus, we assessed whether the toxic effects of exposure in the adulthood differ depending on the presence or absence of neonatal exposure to Tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) in male rats to investigate the effects of exposure history of chemicals. In the neonatal stage [postnatal days (PNDs) 1-7], animals were treated with either sesame oil (5 ml/kg/day) as a control or TDCIPP (250 mg/kg/day) dissolved in sesame oil. In adulthood (PND 101-107), animals were treated with either sesame oil (5 ml/kg/day) or TDCIPP (650 mg/kg/day). One day after the final administration, dissection was performed, and body and organ weight, hematology, blood biochemistry, and histopathology were examined. The results demonstrated that the toxic effects of TDCIPP exposure in adulthood on adrenal gland size, serum iron content, and unsaturated iron binding capacity were enhanced by TDCIPP exposure in the neonatal stage. From these findings, it was indicated that the toxic effects of TDCIPP exposure in the adult stage are affected by pediatric exposure. These results suggest that the toxic effects of high-dose and long-term unsteady exposure to chemicals in large-scale disasters may change based on the exposure history of chemicals.

Effects of Oral Exposure to Low-Dose Bisphenol S on Allergic Asthma in Mice.

Bisphenol S (BPS) is increasingly being used as an alternative for bisphenol A; however, its health effects remain unclear. We investigated the effects of oral exposure to low-dose BPS on allergic asthma. C3H/HeJ male mice were intratracheally administered with allergen (ovalbumin (OVA), 1 µg/animal) every 2 weeks from 6 to 11 weeks old. BPS was ingested by drinking water at doses equivalent to 0.04, 0.4, and 4 µg/kg/day. We then examined pulmonary inflammation, airway hyperresponsiveness, serum OVA-specific immunoglobulin (Ig) levels, Th2 cytokine/chemokine production, and mediastinal lymph node (MLN) cell activities. Compared with OVA alone, moderate-dose BPS (BPS-M) with OVA significantly enhanced pulmonary inflammation, airway hyperresponsiveness, and OVA-specific IgE and IgG1. Furthermore, interleukin (IL)-5, IL-13, IL-33, and CCL11/Eotaxin protein levels in the lungs increased. Conversely, these allergic responses were reduced in the high-dose BPS+OVA group. In MLN cells, BPS-M with OVA increased the total cell count and activated antigen-presenting cells including conventional dendritic cell subset (cDC2). After OVA restimulation, cell proliferation and Th2 cytokine production (IL-4, IL-5, and IL-13) in the culture supernatant also increased. Therefore, oral exposure to low-dose BPS may exacerbate allergic asthmatic responses by enhancing Th2-polarized responses and activating the MLN cells.

Dietary Exposure to Flame Retardant Tris (2-Butoxyethyl) Phosphate Altered Neurobehavior and Neuroinflammatory Responses in a Mouse Model of Allergic Asthma.

Tris (2-butoxyethyl) phosphate (TBEP) is an organophosphate flame retardant and used as a plasticizer in various household products such as plastics, floor polish, varnish, textiles, furniture, and electronic equipment. However, little is known about the effects of TBEP on the brain and behavior. We aimed to examine the effects of dietary exposure of TBEP on memory functions, their-related genes, and inflammatory molecular markers in the brain of allergic asthmatic mouse models. C3H/HeJSlc male mice were given diet containing TBEP (0.02 (TBEP-L), 0.2 (TBEP-M), or 2 (TBEP-H) µg/kg/day) and ovalbumin (OVA) intratracheally every other week from 5 to 11 weeks old. A novel object recognition test was conducted in each mouse at 11 weeks old. The hippocampi were collected to detect neurological, glia, and immunological molecular markers using the real-time RT-PCR method and immunohistochemical analyses. Mast cells and microglia were examined by toluidine blue staining and ionized calcium-binding adapter molecule (Iba)-1 immunoreactivity, respectively. Impaired discrimination ability was observed in TBEP-H-exposed mice with or without allergen. The mRNA expression levels of N-methyl-D aspartate receptor subunits Nr1 and Nr2b, inflammatory molecular markers tumor necrosis factor-α oxidative stress marker heme oxygenase 1, microglia marker Iba1, and astrocyte marker glial fibrillary acidic protein were significantly increased in TBEP-H-exposed mice with or without allergen. Microglia and mast cells activation were remarkable in TBEP-H-exposed allergic asthmatic mice. Our results indicate that chronic exposure to TBEP with or without allergen impaired object recognition ability accompanied with alteration of molecular expression of neuronal and glial markers and inflammatory markers in the hippocampus of mice. Neuron-glia-mast cells interaction may play a role in TBEP-induced neurobehavioral toxicity.

Dietary exposure to bisphenol A affects memory function and neuroimmune biomarkers in allergic asthmatic mice.

Bisphenol A (BPA) is a raw material of polycarbonate and epoxy resin. It is used for various household electrical appliances, electronic equipment, office automation equipment, medical equipment, mobile phones, paints for automobiles, internal surface coating of cans, and adhesives for civil engineering and construction. BPA is a well-known endocrine-disrupting chemical, and it was reported that BPA has an adverse effect on the nervous and immune systems. However, BPA-induced memory impairment and changes in neuroimmune biomarkers in the allergic asthmatic subject are not known yet. We aim to investigate the dietary exposure effect of BPA on brain function and biomarkers using allergic an asthmatic mouse model. Five-week-old male C3H/HeJSlc mice were fed two doses of BPA [0.901, 9.01 µg/kg/day] contained chow diet from 5 to 11 weeks old and ovalbumin (OVA) was given by intratracheal instillation every 2 weeks. Memory function was determined by a novel object recognition test. Genes related to memory and immune markers in the hippocampus were investigated with the real-time polymerase chain reaction (RT-PCR) method. In this study, impaired novel object recognition occurred in BPA-exposed mice in the presence of an allergen. Moreover, upregulation of expression level of neuroimmune biomarkers such as N-methyl-D-aspartate receptor, tumor necrosis factor-α, ionized calcium-binding adapter molecule-1, cyclooxygenase-2, and heme oxygenase-1 in the hippocampus was observed in BPA-exposed allergic asthmatic mice. These findings show that BPA exposure can induce neuroinflammation and which triggers impairment of memory function in mice with allergic asthma. Our study indicated that dietary exposure to BPA may affect higher brain functions by modulating neuroimmune biomarkers in allergic asthmatic subjects.

Novel toxicity of tris(1,3-dichloro-2-propyl) phosphate in adult male rats.

The widespread use of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) as a flame retardant has led to its release to the environment. Thus, the toxicological effects of TDCIPP on humans and animals are of importance. For better understanding of its potential toxicities, TDCIPP (250, 500, or 650 mg/kg/day) or vehicle control was administrated orally to adult male Wistar-Imamichi rats for 7 days. After the final administration of compounds, organ weights, histopathology, blood biochemistry, and hematology were examined. Hepatic toxicity was observed at doses ≥ 500 mg/kg/day of TDCIPP, and renal toxicity was observed at 650 mg/kg/day. The anti-androgenic activity of TDCIPP was previously confirmed in vitro and in vivo, but weights of epididymis, an androgen-dependent organ, were not affected by TDCIPP treatment in adults. Serum alkaline phosphatase activity was significantly decreased in all TDCIPP-treated rats independent of dose. Hemoglobin concentration, hematocrit, red blood cell count, and reticulocyte count were decreased in all TDCIPP-treated rats, but mean corpuscular volume, total iron-binding capacity, and serum iron were normal, suggesting that renal anemia was caused by TDCIPP. Together with previous reports on effects of anti-androgenic substances on red blood cell indices, anemia caused by TDCIPP could be due to its anti-androgenic activity. These considerations will contribute to further assessment of the toxicity of the compound.

Impact of dietary exposure to low-dose tris(1,3-dichloro-2-propyl)phosphate in allergic asthmatic mice.

OBJECTIVE: Tris(1,3-dichloro-2-propyl)phosphate (TDCIPP) is an organophosphorus flame retardant that is an alternative to brominated flame retardants. Although TDCIPP can adversely affect human health, information about its effects on immune and allergic responses is scarce. We aimed to investigate the effects of dietary exposure to TDCIPP using less than the human tolerable daily intake (TDI) in allergic asthmatic mice. METHODS: Male C3H/HeJSlc mice were fed a chow diet containing TDCIPP equivalent to 0.02 µg/kg/day (low; L), 0.2 µg/kg/day (medium; M), or 2 µg/kg/day (high; H) and were intratracheally administered ovalbumin (OVA, 1 µg/animal) every 2 weeks from 5 to 11 weeks of age. RESULTS: In OVA-treated mice, TDCIPP-H exposure tended to enhance pulmonary inflammation compared with vehicle exposure. TDCIPP dose-dependently decreased mRNA level of G protein-coupled estrogen receptor (GPER) in the lungs with or without OVA. OVA + TDCIPP-H treatment tended to increase the total cell number and promoted CD4+ cell activation compared with OVA alone treatment in mediastinal lymph nodes. In splenocytes, an increase in the fraction of Breg cells, but not of total B and T cells, and an increase in IL-5 in cell culture supernatants following OVA re-stimulation in OVA + TDCIPP-H-treated mice was observed compared with OVA-alone-treated mice. Moreover, OVA + TDCIPP-H exposure decreased Gr-1 expression in bone marrow (BM) cells. DISCUSSION: These results suggested that dietary exposure to TDCIPP at TDI level slightly enhances allergic diseases, such as allergic asthma, via GPER regulation at inflamed sites and secondary lymphoid tissue and BM cell alternations.

The impact of oral exposure to low-dose tris(2-butoxyethyl) phosphate in allergic asthmatic mice.

Tris(2-butoxyethyl) phosphate (TBEP) is a major organophosphorus flame retardant and has been widely increasing as a substitute for brominated flame retardants. TBEP may have adverse effects on human health; however, its impact on immune and allergic responses remains largely uncharacterized. In this study, the effects of low-dose TBEP comparable with the level of actual human exposure to that of human tolerable daily intake on allergic asthmatic mice were explored. Five-week-old C3H/HeJSlc male mice consumed a diet containing approximately 0.02, 0.2 or 2 µg/kg/day TBEP and were intratracheally administrated ovalbumin (OVA) (1 µg/mouse every 2 weeks from 5 to 11 weeks of age). Exposure to 2 µg/kg/day TBEP with OVA tended to enhance allergic pulmonary inflammation and significantly elevated mRNA levels of interleukin-5, eotaxin-1 and estrogen receptor alpha (ERα) compared with OVA alone. In mediastinal lymph nodes (MLNs), TBEP (0.2 or 2 µg/kg/day) with OVA significantly increased in total cell number and promoted conventional dendritic cell activation than OVA alone; MLN cell proliferation by OVA restimulation was also enhanced in these groups. In the bone marrow (BM), TBEP (0.02 or 0.2 µg/kg/day) with OVA resulted in a net decrease in total cell number and fraction of CCR2+ Gr-1+ cells; the fraction of Gr-1+ cells increased. In conclusion, oral exposure to low-dose TBEP levels equivalent to tolerable daily intake may exacerbate allergic pulmonary inflammation by promoting a skewed T-helper 2 cell response, upregulation of ERα and dysregulation of both MLN and BM microenvironments.

Intraoperative optical coherence tomography (RESCAN® 700) for detecting iris incarceration and iridocorneal adhesion during keratoplasty.

There is no report focusing on the visualization of the iris incarceration or the iridocorneal adhesion during keratoplasty by use of microscope-integrated intraoperative optical coherence tomography (MIOCT). The purpose of this study is to report the usefulness of MIOCT for detecting iris incarceration and iridocorneal adhesions during penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK). MIOCT system was applied both in a patient who underwent PK for corneal leukoma and in a patient who underwent DALK for keratoconus. During the surgeries, we obtained cross-sectional images around the host-graft interface by operating the foot switch of microscope without discontinuing the surgical procedure. Intraoperative MIOCT findings and postoperative outcomes were examined. An iris incarceration at the host-graft interface was visualized during surgery after corneal suture in PK, which allowed surgeons to return the iris to its original position instantly. In DALK, misdirected air into the posterior chamber could also be seen at the end of the DALK. This iridocorneal adhesion was resolved by fluid injection through paracentesis. Secondary glaucoma and graft rejection have not occurred postoperatively in both cases. The MIOCT system provides advantages such as prevention of secondary glaucoma and rejection following PK and DALK.

Low-dose benzo[a]pyrene aggravates allergic airway inflammation in mice.

Benzo[a]pyrene (BaP) reportedly has mutagenic and adjuvant activities. We aimed to determine the effects of low-dose BaP administration on allergic airway inflammation and mediastinal lymph node (MLN) cell activation/proliferation in mice. Male C3H/HeJ mice were intratracheally administered ovalbumin (OVA) every 2 weeks and/or BaP (0, 0.05, 1 and 20 pmol per animal per week) once per week for 6 weeks. The cellular profile of bronchoalveolar lavage (BAL) fluid, histological changes, inflammatory cytokines/chemokines in the lungs, OVA-specific immunoglobulin (Ig) in serum and MLN cell activation/proliferation were examined. BaP administration of 20 pmol with OVA enhanced neutrophil and macrophage accumulation in the lungs. Compared with OVA administration, BaP administration with OVA tended to enhance pulmonary eosinophilia and goblet cell hyperplasia. Furthermore, it increased the levels of interleukin (IL)-5, IL-13, IL-33, monocyte chemoattractant protein-1 and eotaxin in the lungs, and OVA-specific IgG1 in serum, although not dose-dependently. Compared with the vehicle group, IL-6 and tumor necrosis factor-alpha levels were higher in the OVA + 1 pmol BaP group and IL-12 production was higher in the OVA + 20 pmol BaP group. Ex vivo studies showed that co-exposure to OVA and BaP activated the MHC class II and CD86 expression in MLN cells. Exposure to BaP with OVA increased IL-4, IL-5 and interferon gamma levels in culture supernatants of OVA-re-stimulated MLN cells. In conclusion, low-dose BaP can, at least in part, enhance allergic airway inflammation by facilitating Th2 responses and activating MLN cells; a high BaP dose may contribute to activating both Th1 and Th2 responses. Copyright © 2016 John Wiley & Sons, Ltd.

Obese mice are resistant to eosinophilic airway inflammation induced by diesel exhaust particles.

Particulate matter can exacerbate respiratory diseases such as asthma. Diesel exhaust particles are the substantial portion of ambient particulate matter with a <2.5 µm diameter in urban areas. Epidemiological data indicate increased respiratory health effects of particulate matter in obese individuals; however, the association between obesity and diesel exhaust particle-induced airway inflammation remains unclear. We aimed to investigate the differences in susceptibility to airway inflammation induced by exposure to diesel exhaust particles between obese mice (db/db) and lean mice (db/+m). Female db/db and db/+m mice were intratracheally administered diesel exhaust particles or vehicle every 2 weeks for a total of seven times. The cellular profile of bronchoalveolar lavage fluid and histological changes in the lungs were assessed and the lungs and serum were analyzed for the generation of cytokines, chemokines and soluble intercellular adhesion molecule 1. Diesel exhaust particle exposure-induced eosinophilic infiltration in db/+m mice accompanied by T-helper 2 cytokine, chemokine and soluble intercellular adhesion molecule 1 expression in the lungs. In contrast, it induced mild neutrophilic airway inflammation accompanied by elevated cytokines and chemokines in db/db mice. The lungs of db/db mice exhibited decreased expression of eosinophil activators/chemoattractants such as interleukin-5, interleukin-13 and eotaxin compared with those of db/+m mice. In addition, serum eotaxin and monocyte chemotactic protein-1 levels were significantly higher in db/db mice than in db/+m mice. In conclusion, obesity can affect susceptibility to diesel exhaust particle-induced airway inflammation, which is possibly due to differences in local and systemic inflammatory responses between lean and obese individuals.

The alkylphenols 4-nonylphenol, 4-tert-octylphenol and 4-tert-butylphenol aggravate atopic dermatitis-like skin lesions in NC/Nga mice.

Phthalate esters in plastics act as adjuvants for immunoglobulin production, which aggravates allergic disease. However, the effects of alkylphenols (used as plasticizers and surfactants) on atopic dermatitis have not been studied in detail. Therefore, the goal of the present study was to investigate the effects of the alkylphenols 4-nonylphenol (NP), 4-tert-octylphenol (OP) and 4-tert-butylphenol (BP) in a murine model of atopic dermatitis. NC/Nga mice were intraperitoneally administered NP, OP or BP and were subcutaneously injected with mite allergen in one ear to induce atopic dermatitis-like skin lesions (ADSLs). The condition of the skin was observed, and the levels of immunoglobulin in serum and inflammatory cytokines in lesions were determined. NP exacerbated mite allergen-induced ADSLs according to dose. OP and BP also significantly exacerbated skin lesions but not as a function of dose. Alkylphenols tended to increase the levels of IgE and antigen-specific IgG1 in serum. Further, the treatment of the alkylphenols increased the expression in lesions of inflammatory cytokines, interleukin-4 and monocyte chemotactic protein-3. Thymic stromal lymphopoietin levels increased according to ADSL severity. In contrast, the levels of the T-helper 1 cytokines (interleukin-18 and interferon-gamma) decreased. NP, OP or BP may enhance T-helper 2-type immune responses in NC/Nga mice, which aggravates mite allergen-induced ADSLs. Therefore, the uptake of very low levels of alkylphenols may contribute to the increase in the incidence of atopic dermatitis.

Effects of Asian sand dust particles on the respiratory and immune system.

Epidemiologic studies have reported that Asian sand dust (ASD) particles can affect respiratory health; however, the mechanisms remain unclear. We investigated the effects of ASD on airway epithelial cells and immune cells, and their contributing factors to the effects. Human airway epithelial cells were exposed to ASD collected on 1-3 May (ASD1) and on 12-14 May (ASD2) 2011 in Japan and heat-treated ASD1 for excluding heat-sensitive substances (H-ASD) at a concentration of 0, 3, 30 or 90 µg ml(-1) for 4 or 24 h. Furthermore, bone marrow-derived dendritic cells (BMDC) from atopic prone mice were differentiated by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) then these BMDC were exposed to the ASD for 24 h. Also splenocytes as mixture of immune cells were exposed to the ASD for 72 h. All ASD dose dependently reduced viability of airway epithelial cells. Non-heated ASD showed a dose-dependent increase in the protein release of interleukin (IL)-6 and IL-8. The raises induced by ASD1 were higher than those by ASD2. ASD1 and ASD2 also elevated ICAM-1 at the levels of mRNA, cell surface protein and soluble protein in culture medium. In contrast, H-ASD did not change most of these biomarkers. Non-heated ASD showed enhancement in the protein expression of DEC205 on BMDC and in the proliferation of splenocytes, whereas H-ASD did not. These results suggest that ASD affect airway epithelial cells and immune cells such as BMDC and splenocytes. Moreover, the difference in ASD events and components adhered to ASD can contribute to the health effects.

Effects of oral administration of di-(2-ethylhexyl) and diisononyl phthalates on atopic dermatitis in NC/Nga mice.

CONTEXT: Subcutaneous injection of low dose of phthalates causes adjuvant effects on immunoglobulin production. Moreover, intraperitoneal injection of di-(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP) at doses lower than the no-observed-adverse-effect level (NOAEL) causes aggravation of atopic dermatitis-like skin lesions (ADSLs) in mouse models. However, the effects of oral exposure to these phthalates, including their effect on atopic dermatitis (AD) symptoms, remain unclear. OBJECTIVE: To investigate the effects of oral administration of DEHP and DINP at doses lower than the NOAEL on AD in an NC/Nga mouse model. MATERIALS AND METHODS: NC/Nga mice were subcutaneously injected with mite-allergen (Dermatophagoides pteronyssinus) to induce ADSLs and orally administered varying doses of DEHP (0, 8.3, 166.3 or 3325 µg/animal) or DINP (0, 6.6, 131.3 or 2625 µg/animal) once a week for four weeks. Skin disease symptomatology was subsequently evaluated and immunoglobulin production levels in serum and inflammatory cytokine levels in lesion sites were measured. RESULTS: Oral administration of low doses of both DEHP and DINP tended to increase infiltration of eosinophils; degranulation of mast cells and local expression of inflammatory cytokines, interleukin-13 and macrophage inflammatory protein-1 alpha in subcutaneous tissue, whereas DINP administration tended to aggravate allergen-induced ADSL production. CONCLUSIONS: Oral administration of both DEHP and DINP at doses lower than the NOAEL tends to increase the allergic response in animal AD models, but only DINP administration slightly aggravates allergen-induced ADSL production.

Subjective perception of visual field defects using random noise-moving images in patients with glaucoma: A comparison of computer graphics and analog noises.

PURPOSE: Random noise-moving images (noises) can make glaucoma patients with no subjective symptoms aware of visual field abnormalities. To explore this concept, we developed a noise using computer graphics (CG) and investigated the difference in the subjective perception of visual field abnormalities between CG and conventional analog noises. METHODS: We enrolled individuals with glaucoma (205 eyes), preperimetric glaucoma (PPG; 19 eyes), and normal eyes (35 eyes). For a CG noise, a series of still images was made by randomly selecting five monochromatic tones on 2-mm square dots, and these images were drawn at 60 frames per second (fps) to create a noise-moving image. The participants were asked to describe their perceived shadows on a paper. The results were categorized as follows based on the pattern deviation probability map of the Humphrey field analyzer (HFA): "agreement," "partial agreement," "disagreement," and "no response." The glaucoma stage was classified into four stages, from M1 to M4, based on the HFA's mean deviation. RESULT: The detection rates (agreement and partial agreement) were 80.5% and 65.4% for the CG and analog noises, respectively, with CG noise showing a significantly higher detection rate in all glaucoma eyes (P < 0.001). The detection rates tended to increase as the glaucoma stage progressed, and in Stage M3, these were 93.9% and 78.8% for the CG and analog noises, respectively. The PPG eyes did not exhibit subjective abnormalities for both noises. The specificity values were 97.1% and 100% for the CG and analog noises, respectively. CONCLUSION: The CG noise is more effective than the analog noise in evaluating the subjective perception of visual field abnormalities in patients with glaucoma.

Brominated flame retardants stimulate mouse immune cells in vitro.

Brominated flame retardants (BFRs) are widely used in consumer products. Their toxicological effects as endocrine disruptors have been partly examined. However, their immunological effects have not been elucidated. To evaluate the effects of BFRs on immune responses, we investigated whether BFRs affect phenotypes and the function of immune cells in vitro. Here we examined the commercial pentabromodiphenyl ether mixture (DE-71), octabromodiphenyl ether mixture (DE-79), decabromodiphenyl ether mixture (DE-83R), hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA). Splenocytes and bone marrow (BM) cells were prepared from atopic prone NC/Nga mice. Splenocytes were exposed to each BFR for 24 h. BM cells were cultured with granulocyte macrophage-colony stimulating factor (GM-CSF) for 8 days and BM-derived dendritic cells (BMDCs) were exposed to each BFR for 24 h. In another experiment, BM cells were cultured with GM-CSF in the presence of each BFR for 6 days during BMDC differentiation. After exposure, cell surface molecule expression and cytokine production were investigated. Each BFR increased MHC class II and CD86 expression and interleukin (IL)-4 production in splenocytes. DE-71, HBCD and TBBPA increased T cell receptor (TCR) expression in splenocytes. In both experiments, all BFRs except TBBPA increased DEC205 expression in BMDCs. BMDCs that differentiated in the presence of HBCD showed enhanced MHC class II, CD80, CD86 and CD11c expression. The results demonstrate that some BFRs may stimulate immune cells. BFRs can induce or enhance immune/allergic responses by increasing antigen presentation-related molecule expression and IL-4 production.

Expression levels of neuroimmune biomarkers in hypothalamus of allergic mice after phthalate exposure.

Previously, we demonstrated that maternal exposure to phthalates enhances atopic dermatitis in male mouse offspring. However, whether phthalate exposure affects neuroimmune biomarkers in allergic mice has not yet been studied. Di-(2-ethylhexyl) phthalate (DEHP) and di-isononyl phthalate (DINP) are environmental chemicals that are commonly used as plasticizers. This study was designed to investigate the expression levels of neuroimmune biomarkers in the hypothalamus of a murine model of allergic asthma after phthalate exposure throughout juvenility until adulthood. Six-week-old C3H/HeJ Jcl male mice were treated with DEHP or DINP (0, 0.02, 0.4 or 8 nmol per body per week) and ovalbumin (OVA; 1 µg per body per 2 weeks) for 7 weeks intratracheally. On the day after the completion of the phthalate and OVA treatment, the hypothalamus from each mouse was collected, and the mRNA expression levels of neuroimmune biomarkers were examined using a real-time RT-PCR analysis. The mRNA expression levels of the proinflammatory cytokines interleukin (IL)-1ß and tumor necrosis factor (TNF)-α, the chemokine CCL3, the transcription factor nuclear factor (NF)-κB, the oxidative stress marker heme-oxygenase (HO)1, a nerve growth factor, and the microglia marker Iba1 were remarkably up-regulated in the hypothalami of mice treated with 8 nmol of DEHP in the presence of the allergen. However, no significant changes were observed, except for reductions in the TNF-α and CCL2 mRNA levels, in mice exposed to DINP combined with the allergen. This study is the first report to show that high-dose DEHP exposure throughout juvenility until adulthood may induce neuroinflammation by modulating neuroimmune biomarkers in the hypothalami of allergic mice.

Benzo[a]pyrene aggravates atopic dermatitis-like skin lesions in mice.

Background: Benzo[a]pyrene (BaP) affects the immune system and causes mutagenic and carcinogenic effects. Purpose: We aimed to evaluate the effects of systemic exposure to BaP on mite allergen-induced atopic dermatitis (AD)-like skin lesions in mice. Methods: Mite allergen (Dermatophagoides pteronyssinus; Dp) was injected intradermally into the right ears of NC/Nga male mice on eight occasions every 2-3 days. Benzo[a]pyrene was administered intraperitoneally in the equivalent doses of 0, 2, 20, 200, or 2000 µg/kg/day, once a week on four occasions. Results: AD-like skin inflammation related to mite allergen worsened by BaP exposure at 2, 20 µg/kg/day doses; this was in parallel with eosinophil and mast cell infiltration and mast cell degranulation. A trend was also observed toward increased proinflammatory molecule expression, including macrophage inflammatory protein-1 alpha, interleukin (IL)-4, IL-13, and IL-18, in the ear tissue. However, 200 or 2000 µg/kg/day BaP attenuated the enhancing effects. In the regional lymph nodes, 2 µg/kg/day BaP with Dp enhanced antigen-presenting cell and T cell activation compared with Dp alone. Conclusions: This suggests that BaP exposure can aggravate Dp-induced AD-like skin lesions through TH2-biased responses in the inflamed sites and the activation of regional lymph nodes. Therefore, BaP may be responsible for the recent increase in AD incidence.

Effects of multi-walled carbon nanotubes on a murine allergic airway inflammation model.

The development of nanotechnology has increased the risk of exposure to types of particles other than combustion-derived particles in the environment, namely, industrial nanomaterials. On the other hand, patients with bronchial asthma are sensitive to inhaled substances including particulate matters. This study examined the effects of pulmonary exposure to a type of nano-sized carbon nanotube (multi-walled nanotubes: MWCNT) on allergic airway inflammation in vivo and their cellular mechanisms in vitro. In vivo, ICR mice were divided into 4 experimental groups. Vehicle, MWCNT (50 microg/animal), ovalbumin (OVA), and OVA+MWCNT were repeatedly administered intratracheally. Bronchoalveolar lavage (BAL) cellularity, lung histology, levels of cytokines related to allergic inflammation in lung homogenates/BAL fluids (BALFs), and serum immunoglobulin levels were studied. Also, we evaluated the impact of MWCNT (0.1-1 microg/ml) on the phenotype and function of bone marrow-derived dendritic cells (DC) in vitro. MWCNT aggravated allergen-induced airway inflammation characterized by the infiltration of eosinophils, neutrophils, and mononuclear cells in the lung, and an increase in the number of goblet cells in the bronchial epithelium. MWCNT with allergen amplified lung protein levels of Th cytokines and chemokines compared with allergen alone. MWCNT exhibited adjuvant activity for allergen-specific IgG(1) and IgE. MWCNT significantly increased allergen (OVA)-specific syngeneic T-cell proliferation, particularly at a lower concentration in vitro. Taken together, MWCNT can exacerbate murine allergic airway inflammation, at least partly, via the promotion of a Th-dominant milieu. In addition, the exacerbation may be partly through the inappropriate activation of antigen-presenting cells including DC.

Size effects of latex nanomaterials on lung inflammation in mice.

Effects of nano-sized materials (nanomaterials) on sensitive population have not been well elucidated. This study examined the effects of pulmonary exposure to (latex) nanomaterials on lung inflammation related to lipopolysaccharide (LPS) or allergen in mice, especially in terms of their size-dependency. In protocol 1, ICR male mice were divided into 8 experimental groups that intratracheally received a single exposure to vehicle, latex nanomaterials (250 microg/animal) with three sizes (25, 50, and 100 nm), LPS (75 microg/animal), or LPS plus latex nanomaterials. In protocol 2, ICR male mice were divided into 8 experimental groups that intratracheally received repeated exposure to vehicle, latex nanomaterials (100 microg/animal), allergen (ovalbumin: OVA; 1 microg/animal), or allergen plus latex nanomaterials. In protocol 1, latex nanomaterials with all sizes exacerbated lung inflammation elicited by LPS, showing an overall trend of amplified lung expressions of proinflammatory cytokines. Furthermore, LPS plus nanomaterials, especially with size less than 50 nm, significantly elevated circulatory levels of fibrinogen, macrophage chemoattractant protein-1, and keratinocyte-derived chemoattractant, and von Willebrand factor as compared with LPS alone. The enhancement tended overall to be greater with the smaller nanomaterials than with the larger ones. In protocol 2, latex nanomaterials with all sizes did not significantly enhance the pathophysiology of allergic asthma, characterized by eosinophilic lung inflammation and Igs production, although latex nanomaterials with less than 50 nm significantly induced/enhanced neutrophilic lung inflammation. These results suggest that latex nanomaterials differentially affect two types of (innate and adaptive immunity-dominant) lung inflammation.