Effects of particulate matter from straw burning on lung fibrosis in mice
Effects of particulate matter from straw burning on lung fibrosis in mice
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秸秆燃烧颗粒物对小鼠肺纤维化的影响
DOI：
10.1016/j.etap.2017.10.001
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发表时间：
2017-12-01
影响因子：
4.3
通讯作者：
Li, Hui-Ping
中科院分区：
文献类型：
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作者：
Hu, Yang;Wang, Liu-Sheng;Li, Hui-Ping
目的：探讨秸秆焚烧颗粒物2.5(PM2.5)对小鼠肺纤维化急性加重的影响及N-乙酰半胱氨酸(NAC)的预防作用。方法：测定秸秆焚烧PM2.5暴露系统中PM2.5的组成、粒径及30min浓度变化。将40只C57BL雄性小鼠随机分为两组：博莱霉素组(BLM+AIR)和博莱霉素组+PM2.5组。小鼠气管内注射博莱曼后第7天，暴露于空气或PM2.5中，每天2次，每次30min，暴露1周或4周后处死小鼠(10只/组)。结果：秸秆焚烧PM2.5主要由有机物组成(74.1%)，其中10.92%的无机物为氯离子，4.64%为钾离子，其他成分为硫酸盐、硝酸盐和亚硝酸盐。组织病理学显示，BLM+PM2.5组肺内炎性细胞浸润、肺泡间隔增宽、肺纤维化程度明显高于BLM+AIR组，暴露4周后这些不良反应的程度大于PM2.5暴露1周后。BLM+PM2.5组也显示巨噬细胞含有特殊物质，随着PM2.5暴露的增加，肺组织胶原沉积增加。BLM+PM2.5组ALF中IL-6和TNF-α水平显著高于BLM+AIR组(P<；0.05)，暴露4周后显著高于PM2.5暴露1周后(P<；0.05)。暴露四周后，BLM+PM2.5组ALF中的转化生长因子-β水平显著高于BLM+AIR组(P<；0.05)。BLM+PM2.5组和BLM+AIR组大鼠外周血中IL-6、TNF-α和TGF-β水平无明显差异。肺组织羟脯氨酸含量随暴露时间的增加而增加，暴露4周后明显高于暴露1周后(P=0.019)。暴露于PM2.5不影响正常小鼠的存活率(100%)，但降低了BLM诱导的IPF小鼠的存活率(30%)，而NAC延长了小鼠的存活率(70%，与BLM+PM2.5相比，P=0.032)。结论：BLM诱导的IPF小鼠暴露于秸秆焚烧PM2.5后，肺组织炎症和纤维化加剧，死亡率增加；NAC增加了小鼠的存活率，表明其具有保护作用。
Objective: To investigate the impacts of particulate matter 2.5 (PM2.5) from straw burning on the acute exacerbation of lung fibrosis in mice and the preventive effects of N-acetylcysteine (NAC).Methods: The composition, particle size, and 30-min concentration change in an exposure system of the PM2.5 from straw-burning were determined. Forty C57BL male mice were equally randomized to two groups: bleomycin (BLM)-induced lung fibrosis with an exposure to air (BLM + air) and BLM + PM2.5 groups. On day 7 after receiving intratracheal injection of BLM, mice were exposed to air or PM2.5 in an exposure system for 30 min twice daily and then sacrificed after one-week or four-week exposure (10 mice/group). Mouse survival, lung histopathology, macrophage accumulation in the lung, and pro-inflammatory cytokine levels in alveolar lavage fluid (ALF) were determined.Results: PM2.5 from straw burning were mainly composed of organic matter (74.1%); 10.92% of the inorganic matter of the PM2.5 were chloride ion; 4.64% were potassium ion; other components were sulfate, nitrate, and nitrite. Particle size was 10nm-2 mu m. Histopathology revealed a greater extent of inflammatory cell infiltration in the lung, widened alveolar septum, and lung fibrosis in the BLM + PM2.5 group than in the BLM + air group and a greater extent of those adverse effects after four-week than after one-week exposure to PM2.5. The BLM + PM2.5 group also showed macrophages containing particular matter and increased pulmonary collagen deposition as the exposure to PM2.5 increased. Interleukin (IL)-6 and TNF-alpha levels in ALF were significantly higher in the BLM + PM2.5 group than in the BLM + air group (P < 0.05) and significantly higher after four-week exposure than after one-week exposure to PM2.5 (P < 0.05). TGF-beta levels in ALF after four-week exposure were significantly higher in the BLM + PM2.5 group than in the BLM + air group (P < 0.05). The levels of IL -6, TNF-alpha, and TGF-beta in peripheral serum were not significantly different in the BLM + PM2.5 and BLM + air groups. Lung hydroxyproline contents increased as the exposure to PM2.5 increased and were significantly higher after four-week than after one-week exposure (P = 0.019). Exposure to PM2.5 did not affect the survival of normal mice (100%) but reduced the survival of mice with BLM-induced IPF (30%), whereas NAC extended the survival (70%, vs. BLM + PM2.5, P = 0,032).Conclusion: Exposure of mice with BLM-induced IPF to PM2.5 from straw burning exacerbated lung inflammation and fibrosis and increased mortality; NAC increased the mouse survival, indicating protective effects.