OBJECTIVE: To explore the effect of transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) on toluene diisocyanate (TDI)-induced allergic airway inflammation in mice. METHODS: Thirty-two mice were randomly divided into AOO group, AOO+5Z-7-Oxozeaenol group, TDI group, and TDI+5Z-7-Oxozeaenol group. Another 32 mice were randomly divided into AOO group, TDI group, TDI +5Z-7-Oxozeaenol group, and TDI +5Z-7-Oxozeaenol + Necrostatin-1 group. TAK1 inhibitor (5Z-7-Oxozeaenol, 5 mg/kg) and/or RIPK1 inhibitor (Necrostatin-1, 5 mg/kg) were used before each challenge. Airway responsiveness, airway inflammation and airway remodeling were assessed after the treatments. We also examined the effect of TDI-human serum albumin (TDI-HSA) conjugate combined with TAK1 inhibitor on the viability of mouse mononuclear macrophages (RAW264.7) using CCK8 assay. The expressions of TAK1, mitogen-activated protein kinase (MAPK) and receptor interacting serine/threonine protease 1 (RIPK1) signal pathway in the treated cells were detected with Western blotting. The effects of RIPK1 inhibitor on the viability of RAW264.7 cells and airway inflammation of the mouse models of TDI-induced asthma were evaluated. RESULTS: TAK1 inhibitor aggravated TDI-induced airway inflammation, airway hyper responsiveness and airway remodeling in the mouse models (P < 0.05). Treatment with TAK1 inhibitor significantly decreased the viability of RAW264.7 cells, which was further decreased by co-treatment with TDI-HSA (P < 0.05). TAK1 inhibitor significantly decreased the level of TAK1 phosphorylation and activation of MAPK signal pathway induced by TDI-HSA (P < 0.05). Co-treatment with TAK1 inhibitor and TDI-HSA obviously increased the level of RIPK1 phosphorylation and caused persistent activation of caspase 8 (P < 0.05). RIPK1 inhibitor significantly inhibited the reduction of cell viability caused by TAK1 inhibitor and TDI-HSA (P < 0.05) and alleviated the aggravation of airway inflammation induced by TAK1 inhibitors in TDI-induced mouse models (P < 0.05). CONCLUSION Inhibition of TAK1 aggravates TDI-induced airway inflammation and hyperresponsiveness and may increase the death of macrophages by enhancing the activity of RIPK1 and causing persistent activation of caspase 8.
Animals ; Asthma/chemically induced* ; Inflammation ; Macrophages ; Mice ; Receptor-Interacting Protein Serine-Threonine Kinases ; Respiratory System ; Toluene 2,4-Diisocyanate/adverse effects*

PURPOSE: Toluene diisocyanate (TDI) is a leading cause of occupational asthma (OA). Periostin is a matricellular protein implicated in type 2 immunity-driven asthma. Its pathogenic role in TDI-OA has not been completely elucidated. The present study was performed to investigate the role of periostin in TDI-OA. MATERIALS AND METHODS: Serum periostin levels were measured in subjects with TDI-OA, asymptomatic TDI-exposure controls (AECs), non-occupational asthmatics (NAs), and unexposed normal controls (NCs). To understand the mechanism by which TDI induces periostin production, primary small airway epithelial cells (SAECs) were cultured under stimulation of TDI and neutrophils from asthmatic patients. RESULTS: Fifty-three subjects with TDI-OA, 71 AECs, 67 NAs, and 83 NCs were enrolled. Serum periostin levels were significantly higher in TDI-OA subjects than in AECs (p=0.001), NAs (p < 0.001), and NCs (p < 0.001). In TDI-exposed subjects (TDI-OA and AEC), the PC20 methacholine levels were significantly lower in subjects with a higher periostin level than in those with a lower periostin level. TDI exposure did not increase periostin production directly by SAECs; however, periostin production increased significantly after co-culture with TDI and neutrophils, which was suppressed by an antioxidant. In addition, increased release of TGF-β1 was noted from SAECs when exposed to TDI and neutrophils, which was also suppressed by an antioxidant. CONCLUSION: These results suggest that an increased periostin level may contribute to the progression of airway inflammation to remodeling in TDI-exposed workers. A high serum periostin level is a potential serologic marker of the phenotype of TDI-OA.
Asthma ; Asthma, Occupational* ; Coculture Techniques ; Epithelial Cells ; Humans ; Inflammation ; Methacholine Chloride ; Neutrophils ; Phenotype ; Reactive Oxygen Species ; Toluene 2,4-Diisocyanate ; Toluene*

BACKGROUND: Plastic resins are complex chemicals that contain toluene diisocyanate (TDI) and/or trimellitic anhydride (TMA), which cause occupational allergies (OA), including respiratory allergies. Serum IgGs against TDI and TMA have been suggested as potential markers of the exposure status and as exploring cause of OA. Although TDI-specific IgG has been examined for suspected OA, TMA-specific IgG is not commonly evaluated in a urethane foam factory. This study therefore investigated both TDI- and TMA-specific IgGs in suspected OA patients and to evaluate the usefulness of the measurement of multiple chemical-specific IgG measurement for practical monitoring. METHODS: Blood samples were collected from two male workers who developed respiratory allergies supposedly caused by occupational exposure to TDI and/or TMA for the presence of TDI- and TMA-specific IgGs. In addition, blood samples from 75 male workers from a urethane foam factory, along with 87 male control subjects, were collected in 2014 and tested for the same IgGs in 2014. The presence and levels of TDI- and TMA-specific serum IgGs were measured using dot blot assays. RESULTS: We found that controls had mean concentrations of TDI- and TMA-specific IgGs of 0.98 and 2.10 μg/mL, respectively. In the two workers with respiratory allergies, the TDI-specific IgG concentrations were 15.6 and 9.51 μg/mL, and TMA-specific IgG concentrations were 4.56 and 14.4 μg/mL, which are clearly higher than those in controls. Mean concentrations of TDI- and TMA-specific IgGs in the factory workers were 1.89 and 2.41 μg/mL, respectively, and are significantly higher than those of the controls (P < 0.001 and P < 0.026 for TDI- and TMA-specific IgGs, respectively). CONCLUSION The workers suspected of OA showed an evidently high level of TDI- and TMA-specific IgG, and these levels in workers at the urethane foam factory were also significantly higher than those in controls. In conclusion, the measurement of TDI- and TMA-specific IgG among workers using plastic resins is helpful to monitor their exposure status.
Adult ; Air Pollutants, Occupational ; adverse effects ; immunology ; Environmental Monitoring ; Humans ; Immunoglobulin G ; blood ; immunology ; Japan ; Male ; Manufacturing and Industrial Facilities ; statistics & numerical data ; Middle Aged ; Occupational Diseases ; blood ; chemically induced ; Occupational Exposure ; adverse effects ; statistics & numerical data ; Phthalic Anhydrides ; immunology ; toxicity ; Respiratory Hypersensitivity ; blood ; chemically induced ; Toluene 2,4-Diisocyanate ; immunology ; toxicity ; Workforce

Toluene diisocyanate (TDI) exposure can directly activate and damage airway epithelium. Folliculin (FLCN) is a protein expressed by human airway epithelial cells (HAECs) to maintain airway epithelial integrity and survival. This study investigated the involvement of FLCN in the pathogenesis of TDI-induced occupational asthma (OA). Enzyme-linked immunosorbent assay was used to measure serum levels of FLCN in TDI-exposed subjects (93 TDI-OA patients and 119 asymptomatic exposed controls (AEC)), 200 non-occupational asthma (NOA) patients and 71 unexposed healthy normal controls (NCs). Significantly more subjects in the TDI-OA and AEC groups had high serum levels of FLCN compared to those in the NOA group (P=0.002 and P=0.001, respectively), all of which were higher than the NC group (all P<0.001). The serum level of FLCN was positively correlated with TDI exposure duration (r=0.251, P=0.027), but was negatively correlated with asthma duration of TDI-OA patients (r=−0.329, P=0.029). TDI-exposed subjects with high FLCN levels had higher serum levels of total IgE than those with lower levels. The effects of TDI exposure on FLCN production was investigated by treating HAECs (A549 cells) with TDI-human serum albumin conjugate, which showed increased expression and release of FLCN and interleukin-8 from HAECs. Co-culture with peripheral blood neutrophils also induced FLCN expression and release from HAECs. In conclusion, TDI exposure and TDI-induced neutrophil recruitment into the airways can activate and stimulate HAECs to produce FLCN, which could be involved in airway inflammation in workers exposed to TDI.
Asthma ; Asthma, Occupational ; Coculture Techniques ; Enzyme-Linked Immunosorbent Assay ; Epithelial Cells ; Epithelium ; Estrone* ; Humans ; Immunoglobulin E ; Inflammation* ; Interleukin-8 ; Neutrophil Infiltration ; Neutrophils ; Serum Albumin ; Toluene 2,4-Diisocyanate* ; Toluene*

Toluene diisocyanate (TDI) is the most important cause of occupational asthma (OA), and various pathogenic mechanisms have been suggested. Of these mechanisms, neurogenic inflammation is an important inducer of airway inflammation. Transient receptor potential melastatin 8 (TRPM8) is a well-established cold-sensing cation channel that is expressed in both neuronal cells and bronchial epithelial cells. A recent genome-wide association study of TDI-exposed workers found a significant association between the phenotype of TDI-induced OA and the single-nucleotide polymorphism rs10803666, which has been mapped to the TRPM8 gene. We hypothesized that TRPM8 located in airway epithelial cells may be involved in the pathogenic mechanisms of TDI-induced OA and investigated its role. Bronchial epithelial cells were treated with TDI in a dose- and time-dependent manner. The expression levels of TRPM8 mRNA and protein were determined by quantitative real-time polymerase chain reaction and western blotting. TDI-induced morphological changes in the cells were evaluated by immunocytochemistry. Alterations in the transcripts of inflammatory cytokines were examined in accordance with TRPM8 activation by TDI. TRPM8 expression at both the mRNA and protein levels was enhanced by TDI in airway epithelial cells. TRPM8 activation by TDI led to significant increases in the mRNA of interleukin (IL)-4, IL-13, IL-25 and IL-33. The increased expression of the cytokine genes by TDI was partly attenuated after treatment with a TRPM8 antagonist. TDI exposure induces increased expression of TRPM8 mRNA in airway epithelial cells coupled with enhanced expression of inflammatory cytokines, suggesting a novel role of TRPM8 in the pathogenesis of TDI-induced OA.
Asthma, Occupational ; Blotting, Western ; Cytokines ; Epithelial Cells* ; Genome-Wide Association Study ; Immunohistochemistry ; Inflammation* ; Interleukin-13 ; Interleukin-33 ; Interleukins ; Neurogenic Inflammation ; Neurons ; Phenotype ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Toluene 2,4-Diisocyanate* ; Toluene*

OBJECTIVETo investigate the effect of occupational exposure to toluene diisocyanate (TDI) on the workers' health.

METHODSA total of 76 workers exposed to TDI (exposure group) and 64 management staff members (control group) were selected from a factory as the study subjects. Area sampling was performed for the place with exposure to TDI according to the method in GBZ 159-2004 Specifications of air sampling for hazardous substances monitoring in the workplace, and gas chromatography was applied to measure the concentration of TDI in workplace air. The workers' personal information was collected with questionnaire, pulmonary ventilation function was determined with a portable spirometer, hematological parameters were analyzed by automatic blood analyzer and blood chemistry analyzer, and the indicators of oxidative damage and energy metabolism were measured by the reagent kit provided by Nanjing Jiancheng Bioengineering Institute. SPSS 17 software was applied for statistical analysis.

RESULTSThe exposure group had significantly lower forced vital capacity (FVC), forced expiratory volume in 1 second(FEV1.0), and FEV1.0/FVC ratio than the control group (P <0.05). Compared with the control group, the exposure group had significantly higher red blood cell count, platelet distribution width, mean platelet volume, lymphocyte count, and neutrophil count(P<0.01), and significantly lower activities of lactate dehydrogenase(LDH), superoxide dismutase, and succinodehydrogenase (SDH)(P <0.01). In the exposure group, the length of exposure was negatively correlated with the activities of SDH and LDH in the serum (r=-0.319, P <0.05; r=-0.239, P <0.05), and the length of exposure was not found to be correlated with the activity of SOD and pulmonary function indices.

CONCLUSIONTDI can induce inflammatory response and lung ventilation function impairment in workers exposed to TDI, as well as oxidative stress and imbalance of energy metabolism. Therefore, it can cause damage to workers' health, and protective measures should be enhanced.

Case-Control Studies ; Erythrocyte Count ; Forced Expiratory Volume ; Humans ; Inflammation ; physiopathology ; L-Lactate Dehydrogenase ; blood ; metabolism ; Leukocyte Count ; Lung ; physiopathology ; Occupational Exposure ; adverse effects ; Pulmonary Ventilation ; Succinate Dehydrogenase ; blood ; metabolism ; Superoxide Dismutase ; metabolism ; Toluene 2,4-Diisocyanate ; adverse effects ; Vital Capacity

Adult ; Air Pollutants, Occupational ; adverse effects ; Health Status ; Humans ; Male ; Middle Aged ; Occupational Exposure ; adverse effects ; Toluene 2,4-Diisocyanate ; adverse effects ; Young Adult

OBJECTIVES: We established a Wistar rat model of asthma caused by toluene diisocyanate (TDI) exposure, and investigated the relationship between TDI exposure concentrations and respiratory hypersensitivity, airway inflammation, and cytokine secretions in animals, to better understand the mechanism of TDI induced occupational asthma. METHODS: Wistar rats were exposed to two different concentrations of TDI vapor four hours a day for five consecutive days. Bronchoalveolar lavage (BAL) was performed, and differential leucocytes from the BAL fluid were analyzed. Lung histopathological examination was carried out to investigate the inflammatory status in the airways. Production of cytokines interleukin (IL)-4 and IL-5 productions in the BAL fluid in vivo was determined with enzyme-linked immunosorbent assay kits. RESULTS: The TDI-exposed rats exhibited greater airway hypersensitivity symptoms than the control rats. The BAL differential cell count and lung histopathological examination demonstrated that inflammation reactions were present in both the central and peripheral airways, characterized with marked infiltration of eosinophils in the TDI-exposed rats. The cytokine assay showed that IL-4 and IL-5 were predominantly produced in the BAL fluid in vivo. CONCLUSIONS: These findings imply that TDI exposure concentrations may greatly affect the occurrence and extent of inflammatory events and that Th2 type cytokines may play an important role in the immunopathogenesis of TDI-induced occupational respiratory hypersensitivity.
Animals ; Bronchoalveolar Lavage Fluid/chemistry/cytology ; Enzyme-Linked Immunosorbent Assay ; Eosinophils/cytology/immunology ; Female ; Gases/chemistry ; Hypersensitivity/pathology ; Interleukin-4/*analysis ; Interleukin-5/*analysis ; Lung/*drug effects/pathology/secretion ; Rats ; Rats, Wistar ; Toluene 2,4-Diisocyanate/*toxicity

AIM: To investigate the active chloroform fraction of the ethanol extract of Ipomoea carnea flowers on hematological changes in toluene diisocyanate-induced inflammation in Wistar rats. METHOD: Except for the control group, all of the rats were sensitized with intranasal application of 5 μL of 10% toluene diisocyanate (TDI) for 7 days. One week after second sensitization, all of the rats were provoked with 5 μL of 5% TDI to induce airway hypersensitivity. After the last challenge, blood and bronchoalvelor lavage (BAL) fluid were collected and subjected to total and differential leucocytes count. Flash chromatography was performed on the most active chloroform fraction to isolate an individual component. RESULTS: Treatment with the ethanolic extract and its chloroform fraction at an oral dose of 200 mg·kg⁻¹ showed a significant decrease in circulating neutrophil and eosinophil in blood and BAL as compared with standard dexamethasone (DEXA). The structure of the compound obtained from chloroform fraction of Ipomea carnea was elucidated as stigmast-5, 22-dien-3β-ol on the basis of spectral data analysis. CONCLUSION The chloroform fraction was found to be more effective to suppress airway hyper reactivity symptoms, and decreased count of both total and differential inflammatory cells.
Animals ; Asthma ; blood ; chemically induced ; drug therapy ; metabolism ; Bronchoalveolar Lavage Fluid ; Eosinophils ; metabolism ; Female ; Flowers ; chemistry ; Hematology ; Inflammation ; blood ; chemically induced ; drug therapy ; metabolism ; Ipomoea ; chemistry ; Leukocyte Count ; Male ; Molecular Structure ; Neutrophils ; metabolism ; Phytotherapy ; Plant Extracts ; chemistry ; pharmacology ; therapeutic use ; Rats ; Rats, Wistar ; Stigmasterol ; analogs & derivatives ; chemistry ; isolation & purification ; pharmacology ; therapeutic use ; Toluene 2,4-Diisocyanate

OBJECTIVETo investigate the effect of long-term exposure to toluene diisocyanate (TDI) on the lung function of TDI-exposed workers.

METHODSA factory was selected for this occupational epidemiological investigation. The workers who were exposed to TDI and had complete physical examination records in recent 3 years were the exposed group (n = 45), while the company's administrative staff, logistics staff, and other non-TDI-exposed workers who had complete physical examination records in recent 3 years were the control group (n = 47). The two groups were compared in terms of lung function indices.

RESULTSCompared with the control group, the 2009 exposure group had significantly lower forced expiratory volume in one second (FEV1.0), FEV1.0/forced vital capacity (FVC), and maximal expiratory flow at 25% of FVC (MEF25) (P < 0.05), the 2010 exposure group had significantly lower FEV1.0, FEV1.0/FVC,maximum voluntary ventilation (MVV), and maximal expiratory flow at 50% of FVC (MEF50) (P < 0.05), and the 2011 exposure group had significantly lower FEV1.0, FEV1.0/FVC, peak expiratory flow (PEF), MEF25, and MEF50 (P < 0.05).

CONCLUSIONLong-term exposure to TDI can lead to certain impairment of lung function in workers, which may be reflected by decreased lung function indices such as vital capacity, FVC, FEV1.0, FEV1.0/FVC, PEF, and MVV.

Case-Control Studies ; Forced Expiratory Volume ; Humans ; Lung ; drug effects ; physiopathology ; Male ; Occupational Exposure ; Toluene 2,4-Diisocyanate ; adverse effects ; Vital Capacity ; drug effects