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养猪生产者长期呆在猪舍中,容易患呼吸道疾病,但是关于长期暴露于猪舍空气中导致肺功能障碍的机理仍不清楚。因此,我们提出了多次暴露于猪舍空气中将导致慢性肺炎和造成功能低下的假说,并用小鼠模型验证了这一假说。小鼠被置于猪舍或周围的空气中,8 h/d,分别为1、5、20d 3个组。暴露后测定气道对乙酰甲胆碱是否有高敏感性,然后对鼠施以无痛致死术,收集支气管肺泡的灌洗液、血液和肺组织。猪舍空气取样测定细菌毒素水平和微生物含量。试验结果表明,本试验所用的猪舍空气含有高浓度的细菌毒素(15361.75+7712.16 EU/m3)。暴露天数为1 d和5 d的小鼠,与暴露天数为20 d和对照组的小鼠相比,气道敏感性有增高的趋势。3个暴露组中性白细胞数和嗜酸性细胞增加,5d和20 d暴露组气道上皮杯状细胞有增加的趋势都表明暴露组的鼠的肺发炎。暴露天数为1 d和20 d的鼠,其支气管肺泡灌洗液中总白细胞数较多,且20 d组的小鼠气道上皮杯状细胞较多,与对照组和其他2个试验组相比,差异显著(P<0.05)。20 d暴露组的小鼠,肺部与支气管相连的淋巴组织出现生发中心和有丝分裂细胞,表明淋巴组织被激活。各组气道平滑肌细胞和间隔的巨噬细胞的增加数量都差异。因此,通过试验可知,多次暴露于含有细菌毒素的猪舍空气中将导致气道的高敏感性和肺炎,增加粘液中气道上皮细胞的数量。同时表明,增加暴露时间可使试验鼠适应气道的高敏感性反应。
Pig producers are permanently exposed to pigsty and susceptible to respiratory illnesses, but the mechanisms by which long-term exposure to the air in pigsty lead to pulmonary dysfunction remain unclear. Therefore, we propose the hypothesis that multiple exposure to pigsty air will result in chronic pneumonia and cause hypofunction, and this hypothesis is validated in a mouse model. Mice were housed in or around the pigs air, 8 h / d, respectively 1,5,20 d 3 groups. After exposure, determine if the airway is hypersensitive to methacholine, and then euthanize the rat to collect bronchoalveolar lavage fluid, blood and lung tissue. Air sampling of pigsty to determine bacterial toxin levels and microbial content. The test results showed that the pigs used in this experiment contained a high concentration of bacterial toxins (15361.75 + 7712.16 EU / m3). Mice exposed to days 1 and 5 showed a trend toward increased airway sensitivity compared to mice exposed to 20 days and controls. Neutrophils and eosinophils were increased in the three exposed groups. Increased numbers of goblet cells in the airway epithelium exposed to the 5 and 20 d exposures all showed inflammation of the lungs in the exposed groups. The number of total white blood cells in bronchoalveolar lavage fluid was higher in mice exposed for days 1 and 20, and there were more goblet cells in the airway epithelium in 20 d group. Compared with the control group and the other two experimental groups The difference was significant (P <0.05). Mice in the exposed group on day 20 showed germinal centers and mitotic cells in the lymphoid tissues associated with the bronchi in the lungs, indicating that lymphoid tissue is activated. The number of airway smooth muscle cells and interstitial macrophages in each group increased in number. Therefore, it has been shown through experiments that repeated exposure to the air of pigsty containing bacterial toxins will lead to high airway sensitivity and pneumonia, increasing the number of airway epithelial cells in mucus. At the same time, it is indicated that the experimental mice can adapt to the hypersensitivity reaction of airway by increasing the exposure time.