Korea Conformity Laboratory, Incheon, Korea.
Nanotoxicology. 2013 Mar;7(2):169-80. doi: 10.3109/17435390.2011.648223. Epub 2012 Jan 20.
In a previous study, the lung function, as indicated by the tidal volume, minute volume, and peak inspiration flow, decreased during 90 days of exposure to silver nanoparticles and was accompanied by inflammatory lesions in the lung morphology. Therefore, this study investigated the recovery from such lung function changes in rats following the cessation of 12 weeks of nanoparticle exposure. Male and female rats were exposed to silver nanoparticles (14-15 nm diameter) at concentrations of 0.66 × 10(6) particles/cm(3) (49 μg/m(3), low dose), 1.41 × 10(6) particles/cm(3) (117 μg/m(3), middle dose), and 3.24 × 10(6) particles/cm(3) (381 μg/m(3), high dose) for 6 h/day in an inhalation chamber for 12 weeks. The rats were then allowed to recover. The lung function was measured every week during the exposure period and after the cessation of exposure, plus animals were sacrificed after the 12-week exposure period, and 4 weeks and 12 weeks after the exposure cessation. An exposure-related lung function decrease was measured in the male rats after the 12-week exposure period and 12 weeks after the exposure cessation. In contrast, the female rats did not show a consistent lung function decrease either during the exposure period or following the exposure cessation. The histopathology showed a gradual recovery from the lung inflammation in the female rats, whereas the male rats in the high-dose group exhibited persistent inflammation throughout the 12-week recovery period. Therefore, the present results suggest a potential persistence of lung function changes and inflammation induced by silver nanoparticle exposure above the no observed adverse effect level.
在之前的研究中，潮气量、分钟通气量和吸气峰流速等肺功能在暴露于银纳米粒子 90 天后下降，并伴有肺形态学的炎症损伤。因此，本研究调查了大鼠在停止暴露 12 周纳米颗粒后，从这种肺功能变化中恢复的情况。雄性和雌性大鼠在吸入室中每天暴露于银纳米粒子（直径 14-15nm）浓度为 0.66×10(6)个/立方厘米（49μg/m(3)，低剂量）、1.41×10(6)个/立方厘米（117μg/m(3)，中剂量）和 3.24×10(6)个/立方厘米（381μg/m(3)，高剂量），每天 6 小时，共 12 周。然后允许大鼠恢复。在暴露期间和暴露停止后每周测量肺功能，以及在 12 周暴露期结束后、暴露停止后 4 周和 12 周后处死动物。在 12 周暴露期和暴露停止后 12 周，雄性大鼠的肺功能与暴露有关，出现下降。相比之下，雌性大鼠在暴露期间或暴露停止后均未出现一致的肺功能下降。组织病理学显示，雌性大鼠的肺部炎症逐渐恢复，而高剂量组的雄性大鼠在整个 12 周恢复期间持续存在炎症。因此，本研究结果表明，银纳米颗粒暴露在无观察到不良效应水平以上，可能会持续引起肺功能变化和炎症。
