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Exposure to PM 2.5 can aggravate the occurrence and development of bronchial asthma and fibrosis. Here, we investigated the differences in bronchial injury caused by different exposure modes of PM 2.5 (high concentration intermittent exposure and low concentration continuous exposure), and the mechanism of macrophage activation and respiratory immune imbalance induced by PM 2.5 , leading to bronchial asthma and airway fibrosis using animal and cell models. A "PM 2.5 real-time online concentrated animal whole-body exposure system" was used to conduct PM 2.5 respiratory exposure of Wistar rats for 12 weeks, which can enhance oxidative stress in rat bronchus, activate epithelial cells and macrophages, release chemokines, recruit inflammatory cells, release inflammatory factors and extracellular matrix, promote bronchial mucus hypersecretion, inhibit the expression of epithelial cytoskeletal proteins, destroy airway barrier, and induce asthma. Furthermore, PM 2.5 induced M2 polarization in lung bronchial macrophages through JAK/STAT and PI3K/Akt signaling pathways, and compared with low concentration continuous exposure, high concentration intermittent exposure of PM 2.5 could regulate significantly higher expression of TIPE2 protein through promoter methylation of TIPE2 DNA, thereby activating PI3K/Akt signaling pathway and more effectively inducing M2 polarization of macrophages. Additionally, activated macrophages release IL-23, and activated epithelial cells and macrophages released TGF-β1, which promoted the differentiation of Th17 cells, triggered the Th17 dominant immune response, and activated the TGF-β1/Smad2 signaling pathway, finally causing bronchial fibrosis. Moreover, when the total amount of PM 2.5 exposure was equal, high concentration-intermittent exposure was more serious than low concentration-continuous exposure. In vitro experiments, the co-culture models of PM 2.5 with BEAS-2B, WL-38 and rat primary alveolar macrophages further confirmed that PM 2.5 could induce the macrophage activation through oxidative stress and TIPE2 DNA methylation, and activate the TGF-β1/Smad2 signaling pathway, leading to the occurrence of bronchial fibrosis. [Display omitted] • PM 2.5 exposure activated macrophages and epithelial cells to induce airway fibrosis. • PM 2.5 exposure triggered respiratory immune imbalance through Th17 cells activation. • PM 2.5 -induced above toxic effects was induced by oxidative stress mechanism. • PM 2.5 High-dose intermittent exposure is more harm than low-dose continuous exposure. • The difference between different exposure modes was related to TIPE2 DNA methylation. [ABSTRACT FROM AUTHOR]

The molecular mechanisms of PM 2.5 exposure in the male reproductive system, have scarcely been studied. Here, we demonstrate the possible relationship and molecular mechanisms between endoplasmic reticulum stress (ERS), oxidative stress, and reproductive toxicity caused by PM 2.5. A "PM 2.5 real-time online concentrated animal whole-body exposure system" was employed to expose male Wistar rats to PM 2.5 for 12 weeks, which could induce sperm quality decline, apoptosis, inflammation, oxidative stress, ERS, and histopathological damage in the testis. In vitro study on cultured primary testicular spermatogonia and Leydig cells confirmed that treatment with PM 2.5 (0–320 μg/mL) for 24 h decreased cell survival rate, increased reactive oxygen species, lactate dehydrogenase and 8-hydroxydeoxyguanosine levels, induced DNA damage, ERS and apoptosis, and inhibit the secretion and synthesis of testosterone in Leydig cells. These results clarified that ERS pathways triggered by oxidative stress could significantly induce CHOP and caspase-12 activation, which are significantly associated with cell apoptosis. However, oxidative stress and ERS inhibitors significantly inhibited the occurrence of these injuries. In conclusion, PM 2.5 triggers the ERS pathway and induces DNA damage in rat testicular cells through oxidative stress, ultimately leading to cellular apoptosis. Furthermore, high-concentration intermittent inhalation was more harmful than low-concentration continuous inhalation when the total mass of PM 2.5 exposure was the same. [Display omitted] • PM 2.5 can cause reproductive toxicity in male Wistar rats. • PM 2.5 can cause DNA damage and ERS in male rat germ cells through oxidative stress. • PM 2.5 can activate ERS-mediated CHOP and Caspase-12 apoptosis pathways. • PM 2.5 can activate the DNA damage-mediated mitochondrial apoptosis pathway. • High-dose PM 2.5 intermittent exposure is more toxic than low-dose continuous exposure. [ABSTRACT FROM AUTHOR]

Oil mist particulate matter (OMPM) causes acute and chronic diseases and exacerbations. Owing to the characteristics of poor ventilation, high oil mist concentration, and a relatively closed working environment, the existence of OMPM in the cabin is inevitable, and its impact on the health of occupations on ships cannot be ignored. However, compared with several studies that summarized the health effects of OMPM from traditional sources, few studies have focused on the occupational exposure risk of OMPM from oil pollution sources in ships. In this study, we collected OMPM from oil pollution in cabins and assessed the exposure to OMPM from oil pollution and the corresponding health risks through acute exposure experiments in rats. OMPM exposure induces protein regulation in the extracellular matrix and immune responses, leading to severe inflammatory responses. The abundance and composition of the lung microbial community changed significantly. It interferes with the lung metabolite levels. However, more research is needed to fully understand the extent of health risks associated with OMPM exposure. Further research on vulnerable groups exposed to OMPM from ships is needed to inform public health interventions. [Display omitted] • 16S rRNA and metabolomics combined analysis were used to study the effects of oil mist particulate matter (OMPM) on rat lungs. • OMPM exposure caused significant damage to rat lung tissue. • OMPM exposure changed the microbial composition and structure of lung tissue. • Exposure to OMPM caused disturbances of various metabolic pathways in rats. • Altered lung metabolites were significantly associated with lung microbiota. [ABSTRACT FROM AUTHOR]