In vivo immune activation of splenocytes following exposure to tar from Asian sand dust

Air pollution, especially that initiated by particulate matter (PM), has been implicated as a risk factor for several inflammatory diseases. Previously, it was reported that PM enhances immune responses. PM includes the tar fraction that contains polycyclic aromatic hydrocarbons (PAHs), which produce adverse health effects in exposed individuals. However, the influence of the tar fraction (as a component of PM) on splenocytes is not fully understood. The aim of this study was to determine the effects of the tar fraction extracted from PM collected from the atmosphere in Fukuoka, Japan, on mouse splenocytes. ICR mice were administered tar (1 or 5 μg/mouse) intratracheally 4 times at 2-week intervals, and splenocytes from the tar-treated mice were extracted and examined. The parameters determined were proliferation, cytokine concentrations and transcription factors activation. Following tar treatment, splenocyte proliferation increased relative to controls. Concanavalin A (ConA)-induced interleukin (IL)-2 formation and ConA- or lipopolysaccharide (LPS)-induced interferon-γ production were elevated in splenocytes from tar-exposed mice. However, the production of tumor necrosis factor-α and IL-6 induced by LPS was not markedly changed following tar treatment. Further, nuclear factor of activated T cells, but not nuclear factor-κB, was enhanced in splenocytes of tar-exposed mice. Data indicate that tar-activated splenocytes and PM-bound PAHs might contribute to T cell activation in the spleen.

Urban PM2.5 exacerbates allergic inflammation in the murine lung via a TLR2/TLR4/MyD88-signaling pathway

Nevertheless its mechanism has not been well explained yet, PM2.5 is recognized to exacerbate asthma. In the present study, the roles of toll-like receptor (TLR) 2, TLR4 and MyD88, in exacerbation of allergen-induced lung eosinophilia caused by urban PM2.5 was investigated. TLR2-, TLR4-, MyD88-deficient and WT BALB/c mice were intratracheally challenged with PM2.5 +/− ovalbumin (OVA) four times at 2-week intervals. PM2.5 increased neutrophil numbers and KC in bronchoalveolar lavage fluid and caused slight peribronchiolar inflammation in WT mice. However, these changes were attenuated, but not completely suppressed in gene-deficient mice, especially in MyD88^−/− mice. In WT mice, PM2.5 + OVA exacerbated OVA-related lung eosinophilia. This exacerbation includes increase of IL-5, IL-13, eotaxin and MCP-3; infiltration of eosinophils into the airway submucosa; proliferation of goblet cells in the airway epithelium; and the production of antigen-specific IgE and IgG1 in serum. All these effects were stronger in TLR2^−/− mice than in TLR4^−/− mice. In MyD88^−/− mice, this pro-inflammatory mediator-inducing ability was considerably weak and lung pathology was negligible. These results suggest that urban PM2.5 may exacerbate allergic inflammation in the murine lung via a TLR2/TLR4/MyD88-signaling pathway. PM2.5-bound trace microbial elements, such as lipopolysaccharide may be a strong candidate for exacerbation of murine lung eosinophilia.

Differences in allergic inflammatory responses in murine lungs: comparison of PM2.5 and coarse PM collected during the hazy events in a Chinese city

Urban particulate matter (PM) is associated with an increase in asthma. PM2.5 (<PM2.5 μm) and coarse PM (CPM: PM2.5-PM10 μm) were collected from the air in a Chinese city during haze events. The amounts of polycyclic aromatic hydrocarbons (PAHs) were higher in PM2.5 than in CPM. Conversely, microbial elements LPS and β-glucan were much higher in CPM than in PM2.5. Concentrations of Si, Al, Fe, and Ti in CPM were greater than in PM2.5, while Pb, Cu and As concentrations were lower than in PM2.5. When RAW264.7 cells were treated with PM2.5 and CPM, the pro-inflammatory response in the cells was associated with the microbial element levels and attenuated partly by both polymyxin B (PMB) and N-acetylcystein (NAC). The expression of the oxidative stress response gene heme oxygenase1 was associated with PAHs levels. The exacerbating effects of the two-types of PM on murine lung eosinophilia were compared to clarify the role of toxic materials. When BALB/c mice were intratracheally instilled with PM2.5 or CPM (total 0.4 mg) + ovalbumin (OVA), both exacerbated lung eosinophilia along with allergy-relevant biological indicators, such as OVA-specific IgE in serum; enhancement of lung pathology when compared with counterpart samples without OVA. The exacerbating effects were greater in microbial element-rich CPM than in organic chemical-rich PM2.5. These results indicate that microbial elements have more potently exacerbating effects on the development of lung eosinophilia than do organic chemicals. In addition, oxidative stress and transition metals might be associated with the exacerbation of this negative effect.

Effects of Fetal Exposure to Asian Sand Dust on Development and Reproduction in Male Offspring

In recent experimental studies, we reported the aggravating effects of Asian sand dust (ASD) on male reproduction in mice. However, the effects of fetal ASD exposure on male reproduction have not been investigated. The present study investigated the effects of fetal ASD exposure on reproduction in male offspring. Using pregnant CD-1 mice, ASD was administered intratracheally on days 7 and 14 of gestation, and the reproduction of male offspring was determined at 5, 10, and 15 weeks after birth. The secondary sex ratio was significantly lower in the fetal ASD-exposed mice than in the controls. Histologic examination showed partial vacuolation of seminiferous tubules in immature mice. Moreover, daily sperm production (DSP) was significantly less in the fetal ASD-exposed mice than in the controls. DSP in the fetal ASD-exposed mice was approximately 10% less than the controls at both 5 and 10 weeks. However, both the histologic changes and the DSP decrease were reversed as the mice matured. These findings suggest that ASD exposure affects both the fetal development and the reproduction of male offspring. In the future, it will be necessary to clarify the onset mechanisms of ASD-induced male fetus death and male reproductive disorders.

PM2.5 collected in China causes inflammatory and oxidative stress responses in macrophages through the multiple pathways

Air pollution continues to increase in East Asia, particularly in China, and is considered to cause serious health problems. In this study, we investigated the toxicological properties of particulate matter ≤2.5mm (PM2.5) collected in an urban area in China (Shenyang), focusing on inflammation and oxidative stress tightly linked to respiratory diseases. Exposure to PM2.5 significantly increased the expression levels of inflammatory (interleukin-1β and cyclooxygenase-2) and oxidative stress (heme oxygenase1) genes in the mouse macrophages. PM2.5-caused inflammatory response was strongly suppressed by endotoxin neutralizer (polymyxin B) and knock-out of toll-like receptor 4, while oxidative stress was not. On the other hand, an antioxidant (N-acetylcystein) suppressed oxidative stress, but not inflammatory response. These results suggest that PM2.5 in the atmospheric environment of China causes inflammation and oxidative stress in macrophages via separate pathways.

Differences in allergic inflammatory responses between urban PM2.5 and fine particle derived from desert-dust in murine lungs

The biological and chemical natures of materials adsorbed onto fine particulate matter (PM2.5) vary by origin and passage routes. The exacerbating effects of the two samples-urban PM2.5 (U-PM2.5) collected during the hazy weather in a Chinese city and fine particles (ASD-PM2.5) collected during Asian sand dust (ASD) storm event days in Japan-on murine lung eosinophilia were compared to clarify the role of toxic materials in PM2.5. The amounts of β-glucan and mineral components were higher in ASD-PM2.5 than in U-PM2.5. On the other hand, organic chemicals, including polycyclic aromatic hydrocarbons (PAHs), were higher in U-PM2.5 than in ASD-PM2.5. When BALB/c mice were intratracheally instilled with U-PM2.5 and ASD-PM2.5 (total 0.4 mg/mouse) with or without ovalbumin (OVA), various biological effects were observed, including enhancement of eosinophil recruitment induced by OVA in the submucosa of the airway, goblet cell proliferation in the bronchial epithelium, synergic increase of OVA-induced eosinophil-relevant cytokines and a chemokine in bronchoalveolar lavage fluid, and increase of serum OVA-specific IgG1 and IgE. Data demonstrate that U-PM2.5 and ASD-PM2.5 induced allergic inflammatory changes and caused lung pathology. U-PM2.5 and ASD-PM2.5 increased F4/80(+) CD11b(+) cells, indicating that an influx of inflammatory and exudative macrophages in lung tissue had occurred. The ratio of CD206 positive F4/80(+) CD11b(+) cells (M2 macrophages) in lung tissue was higher in the OVA+ASD-PM2.5 treated mice than in the OVA+U-PM2.5 treated mice. These results suggest that the lung eosinophilia exacerbated by both PM2.5 is due to activation of a Th2-associated immune response along with induced M2 macrophages and the exacerbating effect is greater in microbial element (β-glucan)-rich ASD-PM2.5 than in organic chemical-rich U-PM2.5.

Desert dust induces TLR signaling to trigger Th2-dominant lung allergic inflammation via a MyD88-dependent signaling pathway

Asian sand dust (ASD) is known to exacerbate asthma, although its mechanism is not yet well understood. In this study, when the effects on inflammatory response by LPS present in ASD was investigated by measuring the gene expression of cytokines and chemokines in RAW264.7 cells treated with ASD and/or polymyxin B (PMB), the ASD effects were attenuated by PMB, but not completely. When an in vitro study was performed using bone marrow-derived macrophages (BMDMs) from WT, TLR2(-/-), TLR4(-/-), and MyD88(-/-) BALB/c mice and BMDMs from WT, TLR2(-/-), TLR4(-/-), TLR2/4(-/-), TLR7/9(-/-), and MyD88(-/-) C57BL/6J mice, cytokine (IL-6, IL-12) production in BMDMs was higher in ASD-stimulated TLR2(-/-) cells than in TLR4(-/-) cells, whereas it was lower or undetectable in TLR2/4(-/-) and MyD88(-/-) cells. These results suggest that ASD causes cytokine production predominantly in a TLR4/MyD88-dependent pathway. When WT and TLRs 2(-/-), 4(-/-), and MyD88(-/-) BALB/c mice were intratracheally challenged with OVA and/or ASD, ASD caused exacerbation of lung eosinophilia along with Th2 cytokine and eosinophil-relevant chemokine production. Serum OVA-specific IgE and IgG1 similar to WT was observed in TLRs 2(-/-), 4(-/-) mice, but not in MyD88(-/-) mice. The Th2 responses in TLR2(-/-) mice were attenuated remarkably by PMB. These results indicate that ASD exacerbates lung eosinophilia in a MyD88-dependent pathway. TLRs 2 and 4 signaling may be important in the increase in lung eosinophilia. Also, the TLR4 ligand LPS and TLR2 ligand like β-glucan may be strong candidates for exacerbation of lung eosinophilia.

Spatial correlativity of atmospheric particulate components simultaneously collected in Japan

The simultaneous sampling of total suspended particles was performed at 14 sites in Japan during July 2008-June 2009. The spatial correlativity of each particulate composition toward Osaka was obtained for nine selected sites to overview the chemical composition and geographical distribution of particulate components across a wide range of areas nationwide. The spatial correlatives of atmospheric particulate components were extended to an even wider range of areas up to 950 km distance (meso-alpha scale region, >200 km) for a far-reaching distance analysis unique in the literature. Overall, the spatial correlations of ionic species and both organic and elemental carbons were significant, suggesting their shared advections, including their long-range transport from East Asia. Although sulfate ions are widely dispersed across Japan, such is not necessarily correlated with organic and elemental carbon, possibly indicating that the sulfate emission source, including long-range transport, differs from that of carbonaceous particulates. By contrast, the characteristics of spatial correlatives of metallic constituents vary; for example, particulate Pb and Cd show a significantly wide range of spatial correlatives to Osaka, while Mn-though limited to cities neighboring Osaka-shows significant spatial correlations. Other metallic constituents showed no significant spatial correlatives, indicating the effects of local pollutants. Moreover, the extent of the spatial dispersion of the particulate components and the relationships among chemical components were analyzed via factor analysis to highlight the effects of long-range inflow and local original emissions. In this treatment, 13 particulate components among the 19 measured were implicated in long-range transport.

PM2.5-rich dust collected from the air in Fukuoka, Kyushu, Japan, can exacerbate murine lung eosinophilia

PM2.5 can exacerbate asthma. Organic substances adsorbed on PM2.5-rich dust (PM2.5rd) were inactivated by heating at 360 °C. To characterize the role of organic substances, the effects of PM2.5rd and heated PM2.5-rich dust (H-PM2.5 rd) on allergic lung inflammation were investigated. BALB/c mice were intratracheally administered PM2.5rd or H-PM2.5rd with or without ovalbumin (OVA) four times at 2-week intervals. PM2.5rd, but not H-PM2.5rd, caused neutrophilic alveolitis and bronchitis. In the presence of OVA, PM2.5rd caused severe eosinophil infiltration and goblet cells proliferation in airways, along with a marked induction of the Th2 cytokines interleukin (IL)-4 and IL-13, and the eosinophil-related cytokine IL-5 in bronchoalveolar lavage fluid (BALF). OVA + H-PM2.5rd caused a weaker response. PM2.5rd showed adjuvant effects on OVA-specific immunoglobulin E (IgE) and IgG1 production, but H-PM2.5rd showed minimal effects. These findings suggested that PM2.5rd-bound substances might aggravate lung eosinophilia. To clarify the roles of TLR2, TLR4, and MyD88 on cytokine production in PM2.5rd, murine bone marrow-derived macrophages (BMDMs) from wild-type (WT), TLR2(-/-), TLR4(-/-), and MyD88(-/-) BALB/c mice were stimulated with dust. Cytokine production was low or undetectable in TLR4(-/-) cells, but occurred from TLR2(-/-) cells, and production by MyD88(-/-) cells was higher than by TLR4(-/-) cells. These results suggest that TLR4 and TLR2 ligands (LPS and β-glucan, respectively) mainly contributed to cytokines production induced by PM2.5rd. In addition to chemical substances, PM2.5-bound microbial substances might act in inflammatory and allergic lung diseases.

Prevalence and Characteristics of Chemical Intolerance: A Japanese Population-Based Study

Population-based cross-sectional study was performed to estimate the prevalence of chemical intolerance and to examine the characteristics of the sample. A Web-based survey was conducted that included 7,245 adults in Japan. The criteria for chemical intolerance proposed by Skovbjerg yielded a prevalence of 7.5% that was approximately consistent with that reported from a Danish population-based survey. Female gender, older age, and renovation in the house during the past 7 years were positively associated with chemical intolerance. Improvements in the condition were observed with daily ventilation habits. Medical history of atopic dermatitis, allergic rhinitis, food allergy, multiple chemical sensitivity, and depression were associated with chemical intolerance. Fatigue, depressed mood, and somatic symptoms were also positively correlated with chemical intolerance. Better elucidation of the causes, comorbidities, concomitants, and consequences of chemical intolerance has the potential to provide effective solutions for its prevention and treatment.

Aggravation of ovalbumin-induced murine asthma by co-exposure to desert-dust and organic chemicals: an animal model study

BACKGROUND

The organic chemicals present in Asian sand dust (ASD) might contribute to the aggravation of lung eosinophila. Therefore, the aggravating effects of the Tar fraction from ASD on ovalbumin (OVA)-induced lung eosinophilia were investigated.

METHODS

The Tar fraction was extracted from ASD collected from the atmosphere in Fukuoka, Japan. ASD collected from the Gobi desert was heated at 360°C to inactivate toxic organic substances (H-ASD). ICR mice were instilled intratracheally with 12 different test samples prepared with Tar (1 μg and 5 μg), H-ASD, and OVA in a normal saline solution containing 0.02% Tween 80. The lung pathology, cytological profiles in the bronchoalveolar lavage fluid (BALF), inflammatory cytokines/chemokines in BALF and OVA-specific immunoglobulin in serum were investigated.

RESULTS

Several kinds of polycyclic aromatic hydrocarbons (PAHs) were detected in the Tar sample. H-ASD + Tar 5 μg induced slight neutrophilic lung inflammation. In the presence of OVA, Tar 5 μg increased the level of eosinophils slightly and induced trace levels of Th2 cytokines IL-5 and IL-13 in BALF. Also mild to moderate goblet cell proliferation and mild infiltration of eosinophils in the submucosa of airway were observed. These pathological changes caused by H-ASD + OVA were relatively small. However, in the presence of OVA and H-ASD, Tar, at as low a level as 1 μg, induced severe eosinophil infiltration and proliferation of goblet cells in the airways and significantly increased Th2 cytokines IL-5 and IL-13 in BALF. The mixture showed an adjuvant effect on OVA-specific IgG1 production.

CONCLUSIONS

These results indicate that H-ASD with even low levels of Tar exacerbates OVA-induced lung eosinophilia via increases of Th2-mediated cytokines. These results suggest that ASD-bound PAHs might contribute to the aggravation of lung eosinophila.

Lung inflammation by fungus, Bjerkandera adusta isolated from Asian sand dust (ASD) aerosol and enhancement of ovalbumin-induced lung eosinophilia by ASD and the fungus in mice

Background

Bjerkandera adusta (B. adusta) is one of the most important etiological fungi associated with chronic cough. However, precise details of the inflammatory response to exposure are not well understood yet. B. adusta was recently identified in Asian sand dust (ASD) aerosol. Therefore, in the present study the exacerbating effects of ASD on B. adusta-induced lung inflammation and B. adusta + ASD on ovalbumin (OVA)-induced murine lung eosinophilia were investigated using experimental mice.

Methods

In order to prepare testing samples, B. adusta obtained from ASD aerosol was inactivated by formalin and ASD collected from the atmosphere was heated to remove toxic organic substances (H-ASD). CD-1 mice were instilled intratracheally with 12 different samples prepared with various combinations of B. adusta, H-ASD, and OVA in a normal saline solution. The lung pathology, cytological profiles in bronchoalveolar lavage fluid (BALF), and the levels of inflammatory cytokines/chemokines in BALF were investigated.

Results

H-ASD aggravated the lung eosinophilia induced by B. adusta alone, which also aggravated the lung eosinophilia induced by OVA. The mixture of OVA, H-ASD, and B. adusta caused serious fibrous thickening of the subepithelial layer, eosinophil infiltration, and proliferation of goblet cells in the airways along with remarkable increases of IL-13, eotaxin, IL-5, and MCP-3 in BALF.

Conclusions

The results of the present study demonstrated that B. adusta isolated from ASD aerosol induces allergic lung diseases. H-ASD enhanced allergic reactions caused by OVA or B. adusta. A mixture of B. adusta, H-ASD, and OVA caused the most remarkable exacerbation to the allergic airway inflammation via remarkable increases of pro-inflammatory mediators.

Effects of two Asian sand dusts transported from the dust source regions of Inner Mongolia and northeast China on murine lung eosinophilia

The quality and quantity of toxic materials adsorbed onto Asian sand dust (ASD) are different based on dust source regions and passage routes. The aggravating effects of two ASDs (ASD1 and ASD2) transported from the source regions of Inner Mongolia and northeast China on lung eosinophilia were compared to clarify the role of toxic materials in ASD. The ASDs contained different amounts of lipopolysaccharides (LPS) and β-glucan (ASD1<ASD2) and SiO2 (ASD1>ASD2). CD-1 mice were instilled intratracheally with ASD1, ASD2 and/or ovalbumin (OVA) four times at 2-week intervals. ASD1 and ASD2 enhanced eosinophil recruitment induced by OVA in the submucosa of the airway, with goblet cell proliferation in the bronchial epithelium. ASD1 and ASD2 synergistically increased OVA-induced eosinophil-relevant cytokines interleukin-5 (IL-5), IL-13 (ASD1<ASD2) and chemokine eotaxin (ASD1>ASD2) in bronchoalveolar lavage fluid. ASD2 aggravating effects on lung eosinophilia were greater than ASD1. The role of LPS and β-glucan in ASD2 on the production of pro-inflammatory mediators was assessed using in vitro bone marrow-derived macrophages (BMDMs) from wild type, Toll-like receptor 2-deficient (TLR2-/-), TLR4-/-, and MyD88-/- mice (on Balb/c background). ASD2-stimulated TLR2-/- BMDMs enhanced IL-6, IL-12, TNF-α, MCP-1 and MIP-1α secretion compared with ASD2-stimulated TLR4-/- BMDMs. Protein expression from ASD2-stimulated MyD88-/- BMDM were very low or undetectable. The in vitro results indicate that lung eosinophilia caused by ASD is TLR4 dependent. Therefore, the aggravation of OVA-related lung eosinophilia by ASD may be dependent on toxic substances derived from microbes, such as LPS, rather than SiO2.

Intratracheal administration of fullerene nanoparticles activates splenic CD11b+ cells

Fullerene nanoparticles ("Fullerenes"), which are now widely used materials in daily life, have been demonstrated to induce elevated pulmonary inflammation in several animal models; however, the effects of fullerenes on the immune system are not fully understood. In the present study, mice received fullerenes intratracheally and were sacrificed at days 1, 6 and 42. Mice that received fullerenes exhibited increased proliferation of splenocytes and increased splenic production of IL-2 and TNF-α. Changes in the spleen in response to fullerene treatment occurred at different time-points than in the lung tissue. Furthermore, fullerenes induced CDK2 expression and activated NF-κB and NFAT in splenocytes at 6 days post-administration. Finally, CD11b(+) cells were demonstrated to function as responder cells to fullerene administration in the splenic inflammatory process. Taken together, in addition to the effects on pulmonary responses, fullerenes also modulate the immune system.

Different sensitivity in expression of transcription factor mRNAs in congenic mice following exposure to low-level toluene

To investigate the relationship between sensitivity to toluene exposure and genetic background, male congenic mice, C57BL/10 (H-2(b)) and B10.BR/Sg (H-2(k)) were exposed to 0, 5, and 50 ppm toluene for 6 h per day, 5 days per week for 6 weeks. Groups of mice were injected with ovalbumin (OVA) intraperitoneally before starting exposure schedule and these mice were then challenged with aerosolized OVA as a booster. Following 24 h of the last exposure, the spleens were collected. We examined spleen cell proliferation using DNA synthesis and T-helper 1/2-related transcription factor genes in spleen of two congenic mice using real-time reverse transcriptase-polymerase chain reaction. Although lipopolysaccharide-induced (LPS-induced) cell proliferation was significantly increased in 50 ppm toluene-exposed, nonimmunized B10.BR mice but not in C57BL/10 mice, exposure to 50 ppm toluene significantly decreased LPS-induced cell proliferation in immunized B10.BR mice. The expression of transcription factor forkhead box P3, signal transducers and activators of transcription (STAT)5 and STAT6 mRNAs was significantly increased in spleen from 5 ppm toluene-exposed, OVA-immunized B10.BR mice, but not in those of C57BL/10 mice. Although there may be other differences unrelated to H-2 locus between the congenic mice of the same background, the findings of the present study strongly suggest a possible role of H-2 locus in the toluene-induced immune disturbance.

Modification of the relationship between urinary 8-OHdG and hippuric acid concentration by GSTM1, GSTT1, and ALDH2 genotypes

Urinary hippuric acid (HA) has been widely used as a biological marker of occupational exposure to toluene, although it is no longer valid for low levels of toluene exposure. Toluene exposure is known to induce oxidative DNA damage and the metabolism is affected by genetic polymorphisms of some metabolizing enzymes. Therefore, genetic polymorphisms of these metabolizing enzymes must be considered in the evaluation of oxidative stress caused by toluene exposure. We evaluated the relationship between urinary 8-hydroxydeoxyguanosine (8-OHdG), a marker of oxidative DNA damage, and urinary HA in individuals without occupational exposure to toluene and characterized the possible roles of GSTM1, GSTT1, and aldehyde dehydrogenase 2 (ALDH2) genotypes in the relationships between these markers. In this study, we enrolled 92 healthy Koreans. Urinary HA and 8-OHdG levels were measured and the correlations between them were statistically tested according to the GSTM1, GSTT1, and ALDH2 genotypes. HA did not significantly correlate with urinary 8-OHdG in overall subjects. However, the correlation between them showed a statistical significance in individuals with GSTM1-null, GSTT1-null, and ALDH2 *2/*2 genotypes (r = 0.766, p < 0.01). This study shows that the relationship between urinary HA and 8-OHdG concentration is modified by genetic polymorphisms of some metabolizing enzymes such as GSTM1, GSTT1, and ALDH2.

Strain differences influence N-methyl-D-aspartate receptor subunit gene expression in the olfactory bulb of an allergic mouse model following toluene exposure

OBJECTIVE

Genetic variation is a causative factor in differing sensitivities to environmental chemicals. The present study explored whether differences in mouse strains influence N-methyl-D-aspartate (NMDA) receptor expression in the olfactory bulb after low-level toluene exposure.

METHODS

Ten-week-old male C3H/HeN (H-2(k)), BALB/c (H-2(d)) and C57BL/10 (H-2(b)) mice were exposed to 0, 5, 50 or 500 ppm of toluene for 6 h per day, 5 days per week for 6 weeks. Because individuals with allergic disease are more susceptible to volatile organic compound exposure, the animals of each strain were divided into 2 main groups, a non-allergy (NAG) group and an allergy (AG) group. The AG groups were stimulated with ovalbumin before toluene exposure. The mRNA levels of NMDA receptor subunits (NR1, NR2A and NR2B) in the olfactory bulbs of the NAG and AG groups were examined using real-time RT-PCR.

RESULTS

In C3H/HeN mice, the expression levels of NR1 and NR2B mRNA decreased significantly in the AG group exposed to 500 ppm of toluene; in the NAG group, however, the NR2A mRNA level increased significantly in mice exposed to 50 ppm while the NR2A and NR2B mRNA levels decreased significantly in mice exposed to 500 ppm of toluene. No significant changes were observed in the NAG groups of BALB/c or C57BL/10 mice. However, in the BALB/c mice, the mRNA levels of NR1, NR2A and NR2B decreased significantly in the AG group exposed to 500 ppm of toluene.

CONCLUSION

Mammalian strain differences in NMDA receptor expression after allergic stimulation can be observed in the mouse olfactory bulb after toluene exposure.

Up-regulation of neurotrophin-related gene expression in mouse hippocampus following low-level toluene exposure

To investigate the role of strain differences in sensitivity to low-level toluene exposure on neurotrophins and their receptor levels in the mouse hippocampus, 8-week-old male C3H/HeN, BALB/c and C57BL/10 mice were exposed to 0, 5, 50, or 500 ppm toluene for 6h per day, 5 days per week for 6 weeks in an inhalation chamber. We examined the expressions of neurotrophin-related genes and receptors in the mouse hippocampus using real-time reverse transcription polymerase chain reaction (RT-PCR). The expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), tyrosine kinase (Trk) A, and TrkB mRNAs in the C3H/HeN mice hippocampus was significantly higher in the mice exposed to 500 ppm toluene. Among the three strains of mice, the C3H/HeN mice seemed to be sensitive to toluene exposure. To examine the combined effect of toluene exposure and allergic challenge, the C3H/HeN mice stimulated with ovalbumin were exposed to toluene. The allergy group of C3H/HeN mice showed significantly elevated level of NGF mRNA in the hippocampus following exposure to 50 ppm toluene. Then, we also examined the expression of transcription factor, dopamine markers and oxidative stress marker in the hippocampus of sensitive strain C3H/HeN mice and found that the expression of CREB1 mRNA was significantly increased at 50 ppm toluene. In immunohistochemical analysis, the density of the NGF-immunoreactive signal was significantly stronger in the hippocampal CA3 region of the C3H/HeN mice exposed to 500 ppm toluene in non-allergy group and 50 ppm in allergy group. Our results indicate that low-level toluene exposure may induce up-regulation of neurotrophin-related gene expression in the mouse hippocampus depending on the mouse strain and an allergic stimulation in sensitive strain may decrease the threshold for sensitivity at lower exposure level.

Children's immunology, what can we learn from animal studies (2): Modulation of systemic Th1/Th2 immune response in infant mice after prenatal exposure to low-level toluene and toll-like receptor (TLR) 2 ligand

It has been reported that the newborn immune system differs quantitatively and functionally from that of adults. Development of the immune system has important implications for childhood diseases. The immaturity of the immune system in the prenatal or suckling stage may contribute to susceptibility to environmental toxic chemical exposure. In the present study, to clarify the effect of low-level toluene exposure on immune functions during developmental stage, pregnant mice were exposed to 0, 5, and 50 ppm toluene from gestational day 14 to day 19 with or without stimulation by peptidoglycan (PGN) of a gram-positive bacterial cell wall component, a toll-like receptor (TLR) 2 ligand. We examined Th1/Th2 balance in the offspring's at 3 weeks old using ELISA and real-time RT-PCR methods. Exposure of mice to 50 ppm toluene enhanced total immunoglobulin (Ig) G2a (Th1-dependent) level in plasma. On the other hand, splenic expression of transcription factor T-bet (Th1-specific), GATA-3 (Th2-specific) and Foxp3 (gene marker for regulatory CD4+CD25+ T-cells) mRNAs was suppressed in these mice, but not in the combination of 5 or 50 ppm toluene with PGN. In addition, total IgG1 (Th2 dependent) level was suppressed in the combination of 5 or 50 ppm toluene with PGN. Our findings indicate that modulation of Th1- and Th2-responses may occur in low-level toluene exposure and/or combination with PGN stimulation in infant mice.

Emission rates of air pollutants from portable gas ranges and nitrogen dioxide exposure assessment in restaurants

It is important to characterize the emission of air pollutants and suggest an optimum ventilation rate, because the use of portable gas ranges is widespread in houses and restaurants in Korea. Source emission tests were conducted to characterize the emissions of nitrogen oxide (NOx = NO + NO2), carbon monoxide (CO), carbon dioxide (CO2), formaldehyde (HCHO) and total volatile organic compounds (TVOCs) from portable gas ranges in steady-state using a well-mixed chamber. The ranges of emission rates of air pollutants from portable gas ranges were 0.55-0.94 mg/h for NO, 0.35-1.08 mg/h for NO2, 1.21-1.63 mg/h for NOx 1.39-4.21 mg/h for CO, 2430-2970 mg/h for CO2 and 0-0.12 mg/h for TVOCs. The required mean and maximum ventilation rates to control the air pollutants from portable gas ranges was 2.70 m3/h and 3.13 m3/h on the basis of the NO2 emission rate, respectively. The mean concentrations of food service worker and customer exposures to NO2 by use of portable gas ranges in restaurants were 48.2 +/- 21.5 ppb and 64.7 +/- 31.5 ppb, respectively.

[Questionnaire survey of workers in specific buildings regarding multiple chemical sensitivity]

OBJECTIVES

The purpose of this study was to investigate the incidence of multiple chemical sensitivity (MCS) and effectiveness of the Quick Environment Exposure and Sensitivity Inventory (QEESI) in Japanese workers in specific buildings.

METHODS

The survey was performed in 2004-2006 in Japan. QEESI (Japanese version) and a checklist on accumulation of fatigue developed by the Ministry of Health, Labour and Welfare were used in the examination of 410 workers in specific buildings. Three criteria of QEESI's "symptom severity", "chemical intolerance", and "other intolerance" were evaluated in this study. Clinical histories were also surveyed.

RESULT

Responses were obtained from 368 (89.8%) workers. The results showed that 132 (35.9%) individuals have been diagnosed as having allergy. Only two (0.5%) individuals were found to be MCS patients. There was no sick building syndrome patient. Applying the "high" criteria with QEESI to the standard of Miller and Ashford, we determined that only four (1.1%) individuals met all the three criteria, and 17 (4.6%) individuals met two of the three criteria. The QEESI score of allergy persons was higher than that of nonallergy persons. Among nonallergy persons, those who have a high score on accumulation of fatigue in the checklist showed a high score in QESSI.

CONCLUSIONS

These findings indicated that the QEESI score tended to increase with workload and be high in individuals with allergy. Therefore, careful consideration is required, when QEESI is applied for screening MCS patients in Japan.

Measurement of the physical properties of aerosols in a fullerene factory for inhalation exposure assessment

Assessment of human exposure is important for the elucidation of potential health risks. However, there is little information available on particle number concentrations and number size distributions, including those of nanoparticles, in the working environments of factories producing engineered nanomaterials. The authors used a scanning mobility particle sizer and an optical particle counter to measure the particle number size distributions of particles ranging in diameter (D(p)) from 10 nm to >5000 nm in a fullerene factory and used scanning electron microscopy to examine the morphology of the particles. Comparisons of particle size distributions and morphology during non-work periods, during work periods, during an agitation process, and in the nearby outdoor air were conducted to identify the sources of the particles and to determine their physical properties. A modal diameter of 25 nm was found in the working area during the non-work period; this result was probably influenced by ingress of outdoor air. During the removal of fullerenes from a storage tank for bagging and/or weighing, the particle number concentration at D(p)<50 nm was no greater than that in the non-work period, but the concentration at D(p)>1000 nm was greater during the non-work period. When a vacuum cleaner was in use, the particle number concentration at D(p)<50 nm was greater than that during the non-work period, but the concentration at D(p)>1000 nm was no greater. Scanning electron microscopy revealed that the coarse particles emitted during bagging and/or weighing were aggregates/agglomerates of fullerenes; although origin of particles with D(p)<50 nm is unclear.

[Investigation of air pollution in a shopping center and employees' personal exposure level]

OBJECTIVES

To investigate the concentrations of chemicals found inside a shopping center (SC), we investigated the condition of air pollution in a SC and the personal exposure level of SC employees.

METHODS

The survey was performed in June 2006 in Kyushu. The chemicals studied were volatile organic compounds (VOCs) and aldehydes. The chemicals were collected by a personal passive sampler.

RESULT

Thirty-one VOCs and aldehydes were detected inside the SC. The results showed that the concentrations of all the chemicals detected in indoor air were less than those specified in the indoor air quality guideline of Ministry of Health, Labor and Welfare, Japan. The chemical concentrations in the SC decreased in the order of food corner > electric, clothing corner > outdoor and were clearly higher than those outdoors. Therefore, it is thought that the source of chemicals is indoors. The high indoor concentration of 2-ethyl-1-hexanol may be due to diffusion from the walls and floors. In addition, it is suggested that the personal exposure condition of the employees reflected the indoor concentration of each sales floor. The exposure level to formaldehyde was higher at nonworking time than at working time, suggesting that a larger exposure source exists in the place of residence than in the work place.

CONCLUSIONS

We found that indoor air quality in SC is maintained at good levels. This might be because of the Japanese strict regulations that require administrations of large-scale buildings to provide adequate ventilation and perform regular measurement of indoor air quality.

[Search of streptomycin-resistant bacteria in creek water and application of MALDI-TOF MS to grouping of the isolated bacteria]

A search of streptomycin-resistant bacteria was carried out using ten creek water samples collected in Saga prefecture by spreading the sample water on an R2A medium containing 10 microg/ml of streptomycin. It was clarified that such streptomycin-resistant bacteria as Bacillus, Novosphigobium, Sphingopyxis and Oceanobacillus were distributed in the creek water. Further, 60% of the isolates didn't form an inhibitory zone by the application of 700 microg/ml streptomycin solution in the cup method assay. Further, the effectiveness of the MALDI-TOF MS analysis for the grouping of the isolates was examined. The discriminating ability of MALDI-TOF MS analysis was higher than that of RFLP analysis and it was almost equal to that of sequence analysis using 16S rDNA. Considering the high-throughput ability of the MALDI-TOF MS instrument, MALDI-TOF mass spectral identification of bacteria will be a powerful method in the construction of a MALDI-TOF mass spectra database.

Effects of low-level formaldehyde exposure on synaptic plasticity-related gene expression in the hippocampus of immunized mice

We examined the effects of inhalative exposure to formaldehyde (FA, 400 ppb) on N-methyl-D-aspartate (NMDA) receptor subunits (NR2A and NR2B), dopamine receptor subtypes (D1 and D2), cyclic AMP responsive element-binding protein (CREB)-1, CREB-2, FosB/DeltaFosB, and transient receptor potential vanilloid receptor (TRPV1) in the hippocampus of ovalbumin-immunized mice using quantitative real-time PCR. Western blot analyses for pCREB were performed. The mRNA levels of NR2A, D1 and D2 receptors, and CREB-1 were significantly increased by FA, but NR2B, CREB-2, FosB/DeltaFosB, and TRPV1 mRNA levels remained unchanged. Treatment with MK-801 normalized the mRNA levels induced by FA. There was no significant effect of FA exposure and MK-801 treatment on the protein level of pCREB. These results indicate that FA exposure selectively up-regulates hippocampal gene expression in immunologically sensitized mice. The FA effects are presumably mediated by glutamatergic neurotransmission through NMDA receptors.

Effect of long-term exposure to low-level toluene on airway inflammatory response in mice

Volatile organic compounds are the main substances causing multiple chemical sensitivity reactions in human. Our laboratory has previously showed that the exposure of low-level formaldehyde causes immunogenic and neurogenic inflammatory responses in mice. The aim of the present study was to investigate the effect of long-term, low-level toluene exposure on airway inflammatory responses in mice lung. We exposed female C3H mice to filtered air (0ppm) or 50ppm of toluene for 6h/day on 5days/week for 6 or 12 weeks in the whole body exposure chamber. One day following the last toluene exposure, we collected bronchoalveolar lavage fluid from each mouse and examined cellular infiltration and production of cytokines, chemokines, neurotrophins and substance P by using ELISA method. We found that the number of total cells and macrophages increased significantly in both 6 and 12-week-exposed mice. In addition, the production of interferon-gamma and substance P were decreased significantly and nerve growth factor was not affected in both 6 and 12-week-exposed mice. In contrast, neurotrophin-3 production in bronchoalveolar lavage fluid was significantly increased only in 12-week-exposed mice. Our findings suggest that long-term (12-week) exposure of mice to low-level toluene modulates airway inflammatory response via neurological signaling.

Increased hippocampal mRNA expression of neuronal synaptic plasticity related genes in mice chronically exposed to toluene at a low-level human occupational-exposure

Although neurological symptoms in individuals exposed to toluene both inside and outside the homes have been reported well, the chronic effects of low-level toluene-exposure on the hippocampal expression of neuronal synaptic plasticity related genes have not been studied in vivo. In the present study, to understand the possible adult hippocampal neurobiological responses of mice chronic exposure to toluene at a low-level human occupational-exposure, we exposed 10-week-old C3H/HeN female mice to 50 ppm toluene or filtered air for 6 h a day, on 5-consecutive days of a week for 6 and 12 weeks, in a whole-body exposure chamber. Then, by a quantitative real-time PCR method, we investigated the hippocampal mRNA-expression of several genes, functions of which are necessary to maintain the homeostasis of neuronal synaptic plasticity. We observed that chronic exposure of mice to 50 ppm toluene for a longer period (12 weeks) caused a significant up-regulation of NMDA receptor subunit 2B (NMDA NR2B) expression associated with a simultaneous induction of CaMKIV, CREB-1, and FosB/DeltaFosB in the same hippocampal tissues. Our data indicate that the in vivo transcriptional up-regulation of these genes in the adult hippocampus of our experimental mouse model following the chronic exposure to toluene may be an NMDA-receptor related neuroprotective mechanism of gene expression.

Urinary nicotine and its metabolites as a biomarker of exposure to environmental tobacco smoke

The validity of urinary nicotine and its metabolites as a biomarker of exposure to environmental tobacco smoke (ETS) has been investigated. After exposure to ETS, urine samples were collected from 10 subjects for the analyses of nicotine, cotinine and 3'-hydroxycotinine. The former two chemicals were detected in the urine of all subjects, and 3'-hydroxycotinine was detected in the urine of 9 subjects out of 10, indicating these three chemicals can be used as a biomarker of ETS exposure. 3'-Hydroxycotinine was not detected in the urine of one subject, suggesting that this subject may be a poor metabolizer of nicotine. In 9 subjects with 3'-hydroxycotinine excreted, the amounts of nicotine and cotinine started to increase after exposure, reached the peak at the end of the second exposure and decreased gradually. 3'-Hydroxycotinine started to be excreted into urine from 3 hours after exposure and kept the same level until 72 hours after exposure. In the urine of 72 hours after exposure, the amount of 3'-hydroxycotinine was the highest among these three chemicals.

Measurements of exposure concentrations of benzene, toluene and xylene, and amounts of respiratory uptake

With respect to benzene, toluene, and o-, m- and p-xylene contained in indoor air, this study determined the amounts of their uptake through the human respiratory system using the difference between concentrations in inhalation and exhalation, and examined their relationship to concentrations in blood and urine measured before and after exposure. At relatively high concentrations, respiratory absorption of these compounds tended to increase rapidly in the early stage of exposure but decrease after several hours. It was also confirmed that concentrations of these compounds in both blood and urine increased during the first 3 hours of exposure. These results suggested that measurements of concentrations in inhalation and exhalation may provide a simple method for estimating the extent of respiratory exposure to these substances.

Measurement of volatile organic compounds (VOCs) in new residential buildings and VOCs behavior over time

For the purpose of the investigation of characteristics of VOCs found indoors in recently constructed residential buildings, we measured the behavior of VOCs which were sampled at one-month intervals over a period of one year from the, initial occupancy date in both a detached house and an apartment in a multiple' dwelling. At the first passive sampling from the wooden detached residential building, n-hexane, n-undecane, toluene, ethylacetate, methylethylketone, alpha-pinene and (+)-limonene were present in relatively high concentrations of 10 ppb or higher in the living room. Then these VOCs showed a declining trend with time. p-Dichlorobenzene showed an extremely high concentration (approx. 320 ppb) in June, which subsequently declined with each passing month. There is a high possibility that the cause was the use of a pesticide containing p-dichlorobenzene during the period of changeover from winter to summer clothes in June. On the other hand, from the multiple dwelling, four VOCs showed values of 10 ppb or more (toluene, 1,2,4-trimethylbenzene, methylethylketone and alpha-pinene). Of these VOCs, methylethylketone concentration was in excess of 100 ppb, and then also showed a declining trend with time. Even for new residential buildings completed during the same time frame, it was shown that the types of VOC contaminants and their concentrations varied significantly.

Inhalation of low-level formaldehyde increases the Bcl-2/Bax expression ratio in the hippocampus of immunologically sensitized mice

OBJECTIVE

A recent study from our research group showed that repeated exposure to low-level formaldehyde (FA) increases the production of nerve growth factor, involving the survival and maintenance of neurons, in the hippocampus of immunized mice. In the present study, we examined the effects of FA on apoptotic mechanisms regulating survival and death of cells and on N-methyl-D-aspartate (NMDA) receptors related to hippocampal functions in the mouse hippocampus.

METHODS

Western blot analyses were performed for Bcl-2, Bax and NMDA receptor subtypes 2A and 2B of the hippocampus taken from C3H mice exposed to 0 or 400 ppb of FA with or without ovalbumin (OVA) immunization. Immunohistochemical analysis for active caspase-3 was also carried out for these mice.

RESULTS

The ratio of Bcl-2 to Bax expression levels significantly increased with 400-ppb FA exposure in OVA-immunized mice but not in mice without OVA immunization, although differences in each protein level were not significant among groups. Active caspase- 3-immunoreactive cells were found in the hippocampus. However, the number was only a few and not significantly affected by FA exposure and OVA immunization. NMDA receptor type 2A and 2B expression levels of FA-exposed mice were sustained at comparative levels with those for the control mice with or without OVA immunization.

CONCLUSIONS

These results indicate that changes in the Bcl-2/Bax expression ratio, which occurs with low-level FA exposure and immunization and may follow enhancement of nerve growth factor production, exerts a protective effect against cell death by apoptosis.

Simultaneous analysis of termiticides in indoor air by using gas chromatography mass spectrometry

We have established a method for simultaneously analyzing termiticides (13 kinds) in indoor air based on collection by combination of quartz filter and C18 Empore extraction disks, and measurement using gas chromatography mass spectrometry (GC/MS). The lower limit of determination for each substance was 0.02 microg/m3 when 2 m3 of air was sampled. The recovery was 66-100%, and the relative standard deviation was 3.7-14.2%. In experiments using a model box with commercial termiticides, we verified that emissions of bis (2, 3, 3, 3-tetrachloropropyl) ether (S421) increased with a rise in temperature from 10 degrees C to 20 degrees C to 40 degrees C, whereas almost no etofenprox was released into the air regardless of temperature. In addition, decanal, nonanal and alkanes (C13 and C14), which are major components of termiticides, were detected in relatively high concentrations. In the present study, regardless of low vapor pressure of the termiticides, several compounds were detected with the model box experiment. The conclusion that can be drawn is that it is necessary to survey the indoor environmental pollution.

Hypothalamo-pituitary-adrenal gland axis in mice inhaling toluene prior to low-level long-term exposure to formaldehyde

We studied the change in the hypothalamo-pituitary-adrenal gland (HPA) axis upon adding prior toluene inhalation to our previous formaldehyde inhalation experiments to determine whether short term exposure to relatively high levels of toluene triggers multiple chemical sensitivity (MCS). Data come from immunocytochemical, morphometrical and RT-PCR measurements. Four groups of adult female mice were exposed to differing concentrations (0, 80, 400, and 2,000 ppb) of formaldehyde for 16 hr/day, 5 days/week for twelve weeks, after the mice were exposed intranasally to 500 ppm toluene per mouse for 6 hr/day, for 3 days. We found that the number of corticotropin releasing hormone (CRH)-immunoreactive (ir) neurons was up-regulated according to the amount of formaldehyde as well as inhalation of formaldehyde alone in our previous experiment. The proportion of adrenocorticotropin hormone (ACTH)-ir cells increased according to the formaldehyde concentration, though there was no significant difference between the 400 and 2,000 groups. The number of ACTH-ir cells was higher in the 400 group than in the other groups (0, 80, and 2,000). Expression of ACTH-mRNA was also up-regulated according to the quantity of formaldehyde. The sinusoid in the anterior pituitary showed more dilatation in the 400 and 2,000 groups than in the control group, especially in the 2,000 group. We propose that exposure to toluene prior to inhalation of formaldehyde has no effect on the HPA axis and as a trigger of MCS, although greater sinusoid dilatation was found in the anterior pituitary gland at higher concentrations of formaldehyde.

Effect of prolonged exposure to low concentrations of formaldehyde on the corticotropin releasing hormone neurons in the hypothalamus and adrenocorticotropic hormone cells in the pituitary gland in female mice

We examine the effect on the hypothalamus-pituitary-adrenal gland (HPA) axis of prolonged exposure to low levels of formaldehyde in female C3H/He mice, using immunocytochemical and RT-PCR methods. Two groups of female mice were exposed to differing concentrations (0, 80, 400, 2000 ppb) of formaldehyde inhalation for 16 h/day, 5 days/week, for 12 weeks. The corticotropin releasing hormone (CRH)-immunoreactive (ir) neurons in the hypothalamus were then examined, together with the adrenocorticotropin hormone (ACTH)-ir cells and ACTH mRNA in the pituitary. One group comprised sham control mice. The other group was made allergic by injection of ovalbumin (OVA) and alum prior to exposure to formaldehyde, since most sick building syndrome (SBS) sufferers are women with allergic disease. These animals were further exposed to aerosolized OVA as a booster four times during the exposure period. Our results showed a dose-dependent increase in the number of CRH-ir neurons in the non-allergy (NAG) group. A similar pattern was found in ACTH-ir cells and ACTH mRNA. The allergy (AG) model group showed an increase in basal levels of all markers of HPA activity. Moreover, the AG mice appeared to respond to the lowest concentration of formaldehyde, and all indices of HPA activity were reduced at the highest concentrations of formaldehyde. These results relate to an important clinical issue and also have implications in the broader area of HPA regulation. We conclude that our experimental system may be a suitable animal model for SBS and/or multiple chemical sensitivity (MCS).

[Exposure to formaldehyde during an anatomy dissecting course]

Formaldehyde is a flammable, colorless and readily polymerized gas at ambient temperature, and is one of the major pollutants in indoor air. Medical students during their dissection course are exposed to formaldehyde, whose exposure is recently considered to be one of the causes of multiple chemical sensitivity. To understand the system that produces exposures and to plan for implementing control options, this study examined formaldehyde exposures that occurred in the gross anatomy laboratory. Formaldehyde in air was sampled by an active 2,4-dinitrophenylhydrazine (DNPH)-silica gel cartridge, extracted with acetonitrile and analyzed with an high performance liquid chromatograph-ultraviolet(HPLC-UV)detector. The geometric mean formaldehyde concentration was 20-93 ppb in the anatomy laboratory before starting the anatomy dissecting. After beginning the dissecting, however, the highest geometric mean concentrations were 1012-1380 ppb. Significant differences were observed during the exposed period for symptoms of "unusual thirst", "burning eyes", "itchy eyes", "bad feeling", "fatigue", etc. in comparison with the non-exposed period. These results show that medical schools should take more concrete measures to reduce exposure to formaldehyde.

Long-term exposure to low levels of formaldehyde increases the number of tyrosine hydroxylase-immunopositive periglomerular cells in mouse main olfactory bulb

Multiple chemical sensitivity (MCS) in response to a long-term low-level chemical exposure is as yet an unclarified disorder. To determine the role of olfactory function in the induction of MCS, immunocytochemical analysis of the main olfactory bulb (MOB) was performed after exposure of mice to low levels of formaldehyde. A long-term exposure resulted in an increase in the number of tyrosine hydroxylase-immunopositive periglomerular cells and may affect the neuronal function of the MOB.

Differential immunogenic and neurogenic inflammatory responses in an allergic mouse model exposed to low levels of formaldehyde

It is suspected that exposure to low levels of formaldehyde induces or aggravates airway inflammation mediated by immunological and neurological reactions. To clarify the effect of this exposure on allergic inflammatory responses, we exposed female C3H/He mice to 0, 80, 400, or 2000ppb formaldehyde for 12 weeks. When mice were immunized with ovalbumin (OVA) and then exposed to formaldehyde, the numbers of total bronchoalveolar lavage cells, macrophages, and eosinophils in the mice exposed to 2000ppb formaldehyde were significantly increased compared to 0ppb controls. However, the production of interleukin-1beta from bronchoalveolar lavage fluid of these mice decreased significantly. Immunization with OVA significantly increased the production of nerve growth factor, but exposure to 80 and 400ppb formaldehyde significantly reduced the nerve growth factor levels in bronchoalveolar lavage fluid of the immunized mice. In in vitro study, markedly increased lipopolysaccharide-stimulated interferon-gamma production in culture supernatants of spleen cells from 2000ppb formaldehyde-exposed, nonimmunized mice, and significantly increased OVA-stimulated monocyte chemoattractant protein-1 production in culture supernatants of spleen cells from 400 and 2000ppb formaldehyde-exposed, immunized mice were observed. Exposure to 400ppb formaldehyde induced significant decreases in anti-OVA IgG1 and IgG3 antibody productions in plasma, whereas anti-OVA IgE antibody production was not affected. In addition, the levels of nerve growth factor in plasma of 80 and 400ppb formaldehyde-exposed, immunized mice significantly decreased compared to 0ppb control, immunized mice. These results provide the first experimental evidence that low levels of long-term formaldehyde inhalation can induce differential immunogenic and neurogenic responses in allergic mice.

Effects of green tea on carcinogen-induced hepatic CYP1As in C57BL/6 mice

Green tea (GT) drinking showed chemopreventive effects on various cancers. In addition, inhibition of CYP1A activity by green tea components--polyphenols--has been suggested as a chemoprevention against carcinogens that were bioactivated by CYP1As. Therefore, any changes in hepatic CYP1As may be considered as a biomarker for GT chemoprevention and clarify whether whole GT is chemopreventive for the population who are exposed to CYP1A specifically-bioactivated carcinogens. In this study, we investigated the changes in CYP1A levels by pre- and concurrent GT drinking against a CYP1A-inducing carcinogen, 3-methylcholanthrene (MC), in aryl hydrocarbon receptor responsive C57 BL/6 mice. We found that GT drinking itself induced hepatic CYP1As and enhanced MC-induced ethoxyresorufin-O-demethylase (EROD) activity (P<0.05). However, our studies of CYP1A monoclonal antibody and western blots revealed that the enhanced hepatic EROD activity by GT did not come from CYP1As. Therefore, our results suggest that GT may work to biotransform CYP1A inducing carcinogens into non-carcinogenic metabolites by modulation of other microsomal enzymes rather than CYP1As. In addition, the mechanism of GT chemoprevention may be different from that of GT components, such as polyphenols that reduce CYP1As activity.

Inhalation of low-level formaldehyde enhances nerve growth factor production in the hippocampus of mice

OBJECTIVE

The effects of low-level formaldehyde (FA) inhalation on the amount of nerve growth factor (NGF) in the hippocampus of immunized mice were studied.

METHODS

Evaluation of NGF in the hippocampus was performed by ELISA and RT-PCR.

RESULTS

Exposure to 80 and 400 ppb FA significantly increased the brain NGF levels in the immunized mice. Evaluation of the NGF levels in the hippocampus of immunized mice showed that 400 ppb FA significantly increased the NGF content. The RT-PCR evaluation also showed higher concentrations of hippocampal NGF mRNA in the mice exposed to 80 and 400 ppb FA with immunization.

CONCLUSION

Exposure of immunized mice to low levels of FA significantly increases NGF levels in the hippocampus.

[Synthesis and biological activity of pseudonucleotides based on the evolution hypothesis of the glycocomponent of nucleic acid]

Joyce et al. proposed the hypothesis that the sugar moiety of nucleic acid evolved from some achiral, stable and acyclic sugar into the ribose or the deoxyribose. According to their hypothesis, we designed and synthesized new pseudonucleotides having pentaerythritol moiety as a sugar moiety of nucleic acid and estimated their biological activities. Although all chemicals were not toxic to Lepidium sativum, Rhodotolula rubra and Cercospora kikuchi in the eucaryotes, three compounds having adenine, benzimidazole or 6-chloropurine residue as the base component of nucleotide exhibited the growth inhibiting activity to a prokaryote Spirulina platensis at 100 ppm. In the plaque formation test with Vero cells, a chemical with 6-chloropurine moiety inhibited 65.7% of plaque formation by Herpes simplex virus(HSV-1) at 500 ppm. Three chemicals with 6-chloropurine, 2-mercaptomethylbenzimidazole or guanine as the nucleic base moiety inhibited 62.3, 63.1 and 52.5% of plaque formation by Parainfluenza virus(PIFV) at 500 ppm, respectively. The prepared chemicals exhibited no effect on the Vero cells at the same concentration.