Seidenfeld J J, Sobonya R E, Toyoshima J M
Br J Ind Med. 1985 Mar;42(3):178-83. doi: 10.1136/oem.42.3.178.
New Zealand white rabbits were evaluated for recovery from paraquat induced pneumonitis six weeks after the last exposure. The animals were exposed to a respirable aerosol of 100 ml distilled water or 250 mg paraquat in 100 ml distilled water. Blood gases, breathing frequency, and body weights were recorded before and at regular intervals after exposure. Groups included control and two paraquat exposures (separated by a five day interval). Morphometric and pathological measurements were made at death either three days or 42 days after the second exposure. The animals killed three days after the second exposure showed hypoxia, decreased breathing frequency, decreased body weight, increased A-aO2 gradient, decreased per cent macrophages in bronchoalveolar lavage fluid, increased per cent neutrophils in bronchoalveolar lavage fluid, increased lung weight, and reduced lung volume compared with animals allowed to recover. None of these measures differed between control animals and animals allowed to recover, except that animals exposed to paraquat had significantly increased lung volume and lung weights. Pathological changes noted three days after two exposures were no longer found six weeks after exposure. It is concluded that rabbits exposed to paraquat aerosol develop a severe pneumonitis that resolves if exposure is stopped and recovery time is allowed; physiological abnormalities remain, however.
在最后一次接触百草枯六周后，对新西兰白兔百草枯诱导的肺炎恢复情况进行评估。动物被暴露于100毫升蒸馏水或100毫升蒸馏水中含250毫克百草枯的可吸入气雾剂。在暴露前及暴露后定期记录血气、呼吸频率和体重。分组包括对照组和两次百草枯暴露组（间隔五天）。在第二次暴露后三天或42天处死动物时进行形态学和病理学测量。与允许恢复的动物相比，第二次暴露后三天处死的动物表现出缺氧、呼吸频率降低、体重减轻、肺泡-动脉血氧分压差增加、支气管肺泡灌洗液中巨噬细胞百分比降低、支气管肺泡灌洗液中中性粒细胞百分比增加、肺重量增加和肺容积减小。除了暴露于百草枯的动物肺容积和肺重量显著增加外，对照组动物和允许恢复的动物之间这些指标均无差异。两次暴露后三天观察到的病理变化在暴露六周后不再出现。得出的结论是，暴露于百草枯气雾剂的兔子会发生严重的肺炎，如果停止暴露并给予恢复时间，肺炎会消退；然而，生理异常仍然存在。
