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The influence of PM2.5 on lung injury and cytokines in mice
1Department of Dermatology, Guangdong Academy of Medical Sciences (Guangdong General Hospital), Guangzhou, Guangdong 510080, P.R. China.
Abstract:
Exposure to particulate matter ≤2.5 µm in diameter (PM2.5) profoundly affects human health. However, the role of PM2.5 on lung injury and cytokine levels in mice is currently unknown. The aim was to examine the effect of PM2.5 pollution on lung injury in mice fed at an underground parking lot. A total of 20 female Kunming mice were randomly divided into control and polluted groups, with 10 rats in each group. The control group was kept in the laboratory, while the pollution group was fed in an underground parking lot. The concentrations of pollutants were measured using ambient air quality monitoring instruments. After 3 months of treatment, the lungs were collected and examined using electron microscopy, and the morphological structures were assessed using hematoxylin and eosin staining. The polarization of macrophages was evaluated by immunofluorescence. The concentration of interleukin (IL)-4, tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β1 in peripheral sera were assessed by ELISA. The mRNA and protein levels of IL-4, TNF-α, and TGF-β1 in lung tissues were assessed by reverse transcription-quantitative polymerase chain reaction and western blot analyses, respectively. In the polluted group, the levels of CO, NOx and PM2.5 were significantly higher compared with the control group. Compared with the controls, intracellular edema, an increased number of microvilli and lamellar bodies, smaller lamellar bodies in type II alveolar epithelial cells, and abundant particles induced by PM2.5 in macrophages were observed in the polluted group. The lung ultrastructure changed in the polluted group, revealing exhaust-induced lung injury: The tissues were damaged, and the number of inflammatory cells, neutrophils, polylymphocytes and eosinophils increased in the polluted group compared with the control group. The authors also observed that the number of M1 and M2 macrophages markedly increased after the exhaust treatment. The levels of IL-4, TNF-α and TGF-β1 in the sera and tissues were significantly increased in the polluted group. PM2.5 pollutants in underground garages can lead to lung injury and have a significant impact on the level of inflammatory cytokines in mice. Therefore, the authors suggest that PM2.5 can activate the inflammatory reaction and induce immune dysfunction, leading to ultrastructural damage.
Insights
Exposure to fine particulate matter (PM2.5) in underground parking garages causes lung injury and elevates inflammatory cytokines in mice. This study highlights PM2.5
Area of Science:
- Environmental Health
- Toxicology
- Pulmonary Medicine
Background:
- Particulate matter ≤2.5 µm in diameter (PM2.5) exposure is a significant health concern.
- The specific effects of PM2.5 on lung injury and cytokine profiles in mice remain largely uncharacterized.
Purpose of the Study:
- To investigate the impact of PM2.5 pollution from an underground parking lot on lung injury and inflammatory cytokine levels in mice.
- To assess the ultrastructural changes in lung tissue and the polarization of macrophages following PM2.5 exposure.
Main Methods:
- Female Kunming mice were exposed to an underground parking lot environment (polluted group) or a laboratory setting (control group) for 3 months.
- Lung tissues were analyzed using electron microscopy and hematoxylin and eosin staining for morphological assessment.
- Macrophage polarization was evaluated via immunofluorescence, while cytokine levels (IL-4, TNF-α, TGF-β1) were measured in serum and lung tissue using ELISA, RT-qPCR, and Western blot.
Main Results:
- The polluted group exhibited significantly higher levels of CO, NOx, and PM2.5.
- PM2.5 exposure led to intracellular edema, altered lamellar bodies in type II alveolar cells, and particle accumulation in macrophages.
- Lung tissue damage, increased inflammatory cell infiltration (neutrophils, lymphocytes, eosinophils), and elevated M1/M2 macrophage populations were observed in the polluted group.
- Serum and lung tissue concentrations of IL-4, TNF-α, and TGF-β1 were significantly increased in mice exposed to PM2.5.
Conclusions:
- PM2.5 pollutants in underground garages induce lung injury in mice, characterized by ultrastructural damage and inflammation.
- Exposure to PM2.5 activates inflammatory responses and potentially leads to immune dysfunction.
- These findings underscore the health risks associated with PM2.5 exposure in enclosed environments like underground parking lots.
