Inhalation Toxicology最新文献

Objective: Chronic obstructive pulmonary disease (COPD) is characterized by persistent airway inflammation, with cigarette smoke being a major contributor to epithelial injury. Recent studies have shown that abnormal mitochondrial function is closely linked to the onset and progression of airway inflammation. This study aims to explore the role and underlying molecular mechanisms of mitochondrial dynamics in cigarette smoke-induced airway inflammation.

Materials and methods: Human bronchial epithelial (HBE) cells were exposed to cigarette smoke extract (CSE) to assess the expression of mitochondrial fusion markers MFN2 and OPA1, the fission marker DRP1, and the glucose-regulated protein GRP78. The siRNA and pharmaceutics targeting DRP1, MFN2, and GRP78 were employed. Both cells and supernatants were analyzed for inflammatory factor levels and the related signaling pathways.

Results: In this study, HBE cells exposed to CSE showed a significant decrease in the proteins MFN2 and OPA1 and an increase in DRP1. The inhibition of DRP1 expression mitigated inflammation while silencing MFN2 exacerbated it. This was similarly corroborated by the use of the DRP1 inhibitor mdivi-1 and the MFN2 activator leflunomide. Additionally, we proved that GRP78 played an important regulatory role as an essential endoplasmic reticulum protein, regulating the mitochondrial fusion/fission process and subsequently activating the NF-κB pathway to regulate airway inflammation.

Discussion and conclusion: Taken together, these results suggested that the GRP78-mediated mitochondrial fusion and fission process played a vital role in cigarette smoke-induced airway inflammation and might be a potential therapeutic target in this regard.

Objective: PM_2.5 is closely linked to vascular endothelial injury and has emerged as a major threat to human health. Our previous research indicated that exposure to PM_2.5 induced an increased release of miR-421 from the bronchial epithelium. However, the role of miR-421 in PM_2.5-induced endothelial injury remains elusive.

Materials and methods: We utilized a subacute PM_2.5-exposure model in mice in vivo and an acute injury cell model in vitro to simulate PM_2.5-associated endothelial injury. We also used quantitative real-time polymerase chain reaction, western blot, enzyme-linked immunosorbent assay, and immunohistochemistry to investigate the role of miR-421 in PM_2.5-induced endothelial injury.

Results: Our findings reveal that inhibition of miR-421 attenuated PM_2.5-induced endothelial injury and hypertension. Mechanistically, miR-421 inhibited the expression of angiotensin-converting enzyme 2 (ACE2) in human umbilical vein endothelial cells and upregulated the expression of the downstream molecule inducible nitric oxide synthase (iNOS), thereby exacerbating PM_2.5-induced endothelial injury.

Conclusions: Our results indicate that PM_2.5 exposure facilitates crosstalk between bronchial epithelial and endothelial cells via miR-421/ACE2/iNOS signaling pathway, mediating endothelial damage and hypertension. MiR-421 inhibition may offer a new strategy for the prevention and treatment of PM_2.5-induced vascular endothelial injury.

Objective: Chlorine (Cl₂) is a widely used industrial chemical and toxic human exposures have occurred from Cl₂ releases. No approved medical countermeasures (MCMs) exist for Cl₂-induced lung injuries. The objective of this study was to develop and characterize swine Cl₂ inhalation injuries to understand lung injury and histopathological sequalae.

Materials and methods: Male swine (approximately 14 weeks old) were anesthetized, paralyzed, intubated, and exposed to clean air or Cl₂ while connected to a ventilator. The exposed LD_50/24 hr of 1.8 mg/kg was delivered within a 15-20-minute timeframe. Scheduled terminal timepoints were 6 h, 7- and 30-days post-exposure.

Results: Following Cl₂ exposure, 46% of the animals succumbed with an average time to death of 1.42 h. Dynamic lung compliance at 6 h post-exposure was reduced 45%. Clinical observations demonstrated respiratory abnormalities similar to Cl₂ exposed humans. Compared to air shams, Cl₂-exposed animals had decreased SpO₂, arterial blood pH, pO₂, sO₂, increased blood lactate levels and deoxyhemoglobin levels at early timepoints. Increased neutrophils 6 h post- exposure occurred concurrent with increased inflammatory cytokines, bronchiolar epithelial necrosis with alveolar edema, cellular infiltrates, and lobular atelectasis.

Discussion/conclusions: Potentially relevant biomarkers involved in the progression and recovery from acute Cl₂ lung injury in this model include lung compliance, select cytokines/chemokines, arterial blood gas parameters, and histopathological evaluation. Normal lung histopathological observations beyond 7- days indicates that histopathological evaluations should occur earlier. This animal model delivers accurate and consistent Cl₂ exposures resulting in a human-relevant lung injury for evaluating MCM efficacy against Cl₂-mediated acute lung injury.

Purpose: Airborne pathogen scan penetrate in human respiratory tract and can cause illness. The use of animal models to predict aerosol deposition and study respiratory disease pathophysiology is therefore important for research and a prerequisite to test and study the mechanism of action of treatment. NHPs are relevant animal species for inhalation studies because of their similarities with humans in terms of anatomical structure, respiratory parameters and immune system.

Materials and methods: The aim of this review is to provide an overview of the state of the art of pathogen aerosol studies performed in non-human primates (NHPs). Herein, we present and discuss the deposition of aerosolized bacteria and viruses. In this review, we present important advantages of using NHPs as model for inhalation studies.

Results: We demonstrate that deposition in the respiratory tract is not only a function of aerosol size but also the technique of administration influences the biological activity and site of aerosol deposition. Finally, we observe an influence of a region of pathogen deposition in the respiratory tract on the development of the pathophysiological effect in NHPs.

Conclusion: The wide range of methods used for the delivery of pathogento NHP respiratory airways is associated with varying doses and deposition profiles in the airways.

Objective: Acute intranasal (IN) instillation of lupus-prone NZBWF1 mice with crystalline silica (cSiO₂) triggers robust lung inflammation that drives autoimmunity. Prior studies in other preclinical models show that soluble epoxide hydrolase (sEH) inhibition upregulates pro-resolving lipid metabolites that are protective against pulmonary inflammation. Herein, we assessed in NZBWF1 mice how acute IN cSiO₂ exposure with or without the selective sEH inhibitor TPPU influences lipidomic, transcriptomic, proteomic, and histopathological biomarkers of inflammation, fibrosis, and autoimmunity.

Methods: Female 6-week-old NZBWF1 mice were fed control or TPPU-supplemented diets for 2 weeks then IN instilled with 2.5 mg cSiO₂ or saline vehicle. Cohorts were terminated at 7 or 28 days post-cSiO₂ instillation (PI) and lungs analyzed for prostaglandins, cytokines/chemokines, gene expression, differential cell counts, histopathology, and autoantibodies.

Results: cSiO₂-treatment induced prostaglandins, cytokines/chemokine, proinflammatory gene expression, CD206⁺ monocytes, Ly6B.2⁺ neutrophils, CD3⁺ T cells, CD45R⁺ B cells, centriacinar inflammation, collagen deposition, ectopic lymphoid structure neogenesis, and autoantibodies. While TPPU effectively inhibited sEH as reflected by skewed lipidomic profile in lung and decreased cSiO₂-induced monocytes, neutrophils, and lymphocytes in lung lavage fluid, it did not significantly impact other biomarkers.

Discussion: cSiO₂ evoked robust pulmonary inflammation and fibrosis in NZBWF1 mice that was evident at 7 days PI and progressed to ELS development and autoimmunity by 28 days PI. sEH inhibition by TPPU modestly suppressed cSiO₂-induced cellularity changes and pulmonary fibrosis. However, TPPU did not affect ELS formation or autoantibody responses, suggesting sEH minimally impacts cSiO₂-triggered lung inflammation, fibrosis, and early autoimmunity in our model.

Background: The abnormality of the immune system caused by infection is a contributor to the organ dysfunctions associated with sepsis. The balance between Th17/Treg cells is essential for maintaining immune homeostasis. Bergapten is a natural furocoumarin and has been reported to alleviate the Th17/Treg imbalance. Here, we explored the effects of bergapten on the inflammation and immune state in mouse models of sepsis.

Methods: The model was established using the cecal ligation and puncture method. Mice were administered 30 mg/kg bergapten. Histological examination, RT-qPCR, enzyme-linked immunosorbent assay, immunoblotting, immunofluorescence, immunohistochemistry, and flow cytometry were used to evaluate the effects of bergapten in vivo.

Results: Bergapten ameliorated lung damage, reduced lung wet/dry weight ratio, inhibited myeloperoxidase activity, and reduced inflammatory cell infiltration. Bergapten also restrained sepsis-induced inflammation via inhibition of inflammatory cytokines and NF-κB signaling. These effects were accompanied by the restored Th17/Treg balance induced by bergapten. Bergapten decreased the number of Th17 cells and elevated the number of Tregs, and this effect was mediated by the signal transducer and activator of transcription 5 (STAT5)/Forkhead box P3 (Foxp3) and STAT3/retinoid-related orphan receptor-γt (RORγt) pathways.

Conclusions: Bergapten exerted anti-inflammatory effects in acute lung injury by improving the Th17/Treg balance, which suggested a potential of bergapten as an immunomodulatory drug treating sepsis-associated diseases.

Respiratory co-exposure to ambient PM_2.5 and electronic cigarettes (e-cigarettes) frequently occurs in public. However, the combined effects on human respiratory health have not been well documented. To discuss potential co-effects and possible biological mechanisms, A549/THP-1 co-cultures and BEAS-2B cells were exposed to unvapedtobacco or mint-flavored e-liquids (0-7.2% v/v), e-cigarette aerosol extract (ECE, 0-50% v/v), PM_2.5 (60 μg/mL), or PM_2.5 + ECE for 24 h. Cell viability assessments on e-liquids, ECE, PM_2.5 + ECE showed that the mint flavor exhibited higher cytotoxicity compared to the tobacco flavor in both A549/THP-1 and BEAS-2B. However, the influence of flavors on ROS levels and mRNA expression of inflammatory markers (IL-6, TNF-α, IL-8, IL-1β) after ECE exposure demonstrated inconsistency in the two cell models. PM_2.5 + ECE treatment notably elevated ROS production and inflammation responses compared to ECE alone exposure. Only co-exposure induced a significant increase in nuclear transcription factor-κB p65 (NF-κB p65) and NOD-like receptor 3 (NLRP3) protein expression regardless of flavors. Our results indicate that PM_2.5-treated cells exacerbate the adverse effects induced by ECE in both A549/THP-1 and BEAS-2B cells. Flavors in unvaped e-liquids affect cytotoxicity, oxidative stress and inflammation response, but these effects vary depending on the vaping process and the specific cell line.

Introduction: Particulate matter (PM) air pollution is associated with an increased incidence of lung diseases, but the underlying mechanisms have not been fully elucidated. In this study, a mouse model of subacute lung inflammation was employed to investigate the cellular responses and gene expression changes induced by exposure to natural ambient air pollution.

Methods: C57BL/6J mice were exposed to road dust (primarily PM10) at 150 µg/m³ for 21 days (8 h/day) through a nose-only inhalation exposure system. Lung tissues were analyzed for the expression of proinflammatory signaling, oxidative stress, and fibrosis markers. RNA-sequencing analysis was conducted to identify differentially expressed genes (DEGs). A gene ontology over-representation analysis was performed to identify the altered genetic pathways.

Results: Elevated levels of proinflammatory cytokines, including IL-1β, IL-6, and TNF-α, and an increase in phosphorylated MAPK were determined in the road dust exposure group compared to the control group. Histopathological examinations revealed more severe lung inflammation and damage in the exposed mice, including fibrosis and bronchiolar hyperplasia. Gene expression profiling identified 108 DEGs, with decreases in most except genes such as Krt15 and Reg3g. The protein-protein interaction network analysis together with text-mining identified 18 key hub genes, associated with fatty acid oxidation, lipid metabolism, and peroxisomes.

Conclusion: This study identified key genes, signaling pathways, and cellular responses in mouse lung affected by road dust exposure. These findings contribute to a deeper understanding of the transcriptional and cellular responses induced by subacute exposure to the PM in road dust.

Objective: Cigarette smoking can lead to a host of adverse health effects such as lung and heart disease. Increased lung cancer risk is associated with inhalation of carcinogens present in a puff of smoke. These carcinogenic compounds deposit in the lung at different sites and trigger a cascade of events leading to adverse outcomes. Understanding the site-specific deposition of various smoke constituents will inform the study of respiratory diseases from cigarette smoking. We previously developed a deposition model for inhalation of aerosol from electronic nicotine delivery systems. In this study, the model was modified to simulate inhalation of cigarette smoke consisting of soluble and insoluble tar, nicotine, and cigarette-specific constituents that are known or possible human carcinogens.

Materials and methods: The deposition model was further modified to account for nicotine protonation and other cigarette-specific physics-based mechanisms that affect smoke deposition. Model predictions showed a total respiratory tract uptake in the lung for formaldehyde (99%), nicotine (80%), and benzo[a]pyrene (60%).

Results: The site of deposition and uptake depended primarily on the constituent's saturation vapor pressure. High vapor pressure constituents such as formaldehyde were preferentially absorbed in the oral cavity and proximal lung regions, while low vapor pressure constituents such as benzo[a]pyrene were deposited in the deep lung regions. Model predictions of exhaled droplet size, droplet retention, nicotine retention, and uptake of aldehydes compared favorably with experimental data.

Conclusion: The deposition model can be integrated into exposure assessments and other studies that evaluate potential adverse health effects from cigarette smoking.

Objectives: Living conditions play a major role in health and well-being, particularly for the cardiovascular and pulmonary systems. Depleted housing contributes to impairment and development of disease, but how it impacts body resiliency during exposure to environmental stressors is unknown. This study examined the effect of depleted (DH) versus enriched housing (EH) on cardiopulmonary function and subsequent responses to wildfire smoke. Materials and Methods: Two cohorts of healthy female mice, one of them surgically implanted with radiotelemeters for the measurement of electrocardiogram, body temperature (Tco) and activity, were housed in either DH or EH for 7 weeks. Telemetered mice were exposed for 1 h to filtered air (FA) and then flaming eucalyptus wildfire smoke (WS) while untelemetered mice, which were used for ventilatory assessment and tissue collection, were exposed to either FA or WS. Animals were continuously monitored for 5-7 days after exposure. Results: EH prevented a decrease in Tco after radiotelemetry surgery. EH mice also had significantly higher activity levels and lower heart rate during and after FA and WS. Moreover, EH caused a decreased number of cardiac arrhythmias during WS. WS caused ventilatory depression in DH mice but not EH mice. Housing enrichment also upregulated the expression of cardioprotective genes in the heart. Conclusions: The results of this study indicate that housing conditions impact overall health and cardiopulmonary function. More importantly, depleted housing appears to worsen the response to air pollution. Thus, non-chemical factors should be considered when assessing the susceptibility of populations, especially when it comes to extreme environmental events.