Histopathological changes in a mouse model exposed to fine particulate matter collected from Korean air

초록

Background & Objectives: PM2.5 exposure is widely studied for its association with lung cancer risk. However, most prior studies have relied on standardized commercial PM2.5 samples, which may not fully reflect real-world exposure conditions. To address this, we investigated the potential effects of PM2.5 collected directly from ambient air in South Korea on lung tissue alterations in a murine model. This study aimed to assess how regionally collected PM2.5 influences lung histopathology, focusing on neoplastic changes, inflammation, and fibrosis. Methods: Male A/J mice (7 weeks old) were assigned to four experimental groups: saline control, urethane, PM, and urethane + PM. Following urethane injection (250 mg/kg intraperitoneally), PM2.5 (35 μL) or saline was intranasally administered twice per week for five weeks. PM2.5 samples were collected from ambient air in South Korea using a high-capacity air sampler, then processed and purified for experimental use. Lung tissues were harvested at 40 weeks and evaluated histologically for hyperplasia, adenoma, carcinoma, fibrosis, and inflammation severity. Statistical significance was determined using Kruskal-Wallis and Mann-Whitney tests (p < 0.05). Results: Mice exposed to PM2.5, either alone or in combination with urethane, exhibited a greater tendency for adenoma formation compared to controls. The mean maximum adenoma diameter was larger in both the urethane + PM and PM groups than in the saline group, with the urethane + PM group showing the most pronounced increase. While these findings indicate a possible relationship between PM2.5 exposure and lung tissue alterations, additional studies are necessary to further explore these effects. Conclusion: Our study highlights the potential impact of real-world PM2.5 exposure on lung tissue changes in a murine model. While the observed trends suggest a role for PM2.5 in early neoplastic processes, further validation with expanded sample sizes and mechanistic analyses will be essential for a more comprehensive understanding of its biological effects.