Jankov Robert P, Johnstone Leslie, Luo Xiaoping, Robinson Brian H, Tanswell A Keith
Canadian Institutes of Health Research Group in Lung Development and Lung Biology Programme, Research Institute, The Hospital for Sick Children, Toronto, Canada.
Free Radic Biol Med. 2003 Jul 15;35(2):200-9. doi: 10.1016/s0891-5849(03)00305-8.
The lungs of newborn rats exposed to 60% O(2) for 14 d were found to have a greatly increased cyanide-insensitive O(2) consumption, reflecting increased reactive oxygen species (ROS) formation. Exposure of the lung to hyperoxia is known to increase the production of ROS by mitochondria. We hypothesized that macrophages may also be a major contributor to this increase. Newborn rat pups were exposed to either air or 60% O(2) for 14 d and received either intraperitoneal gadolinium chloride (GdCl(3)) to abrogate macrophage influx, or inert vehicle. Lung homogenates were equilibrated in either 21% or 100% O(2) and total and cyanide-insensitive O(2) consumption, as well as nitric oxide accumulation were measured polarographically. Citrate synthase, a marker of mitochondrial mass, and nitrotyrosine, a marker of peroxynitrite formation, were quantified by Western blot. In addition to increased macrophage numbers, the lungs of 60% O(2)-exposed animals had greatly increased cyanide-insensitive O(2) consumption (p <.05 compared to air controls) and immunoreactive nitrotyrosine (p <.05), which were all completely abrogated by treatment with GdCl(3). Exposure to 60% O(2) for 14 d had no effect on peroxynitrite-independent nitric oxide release or mitochondrial mass. We conclude that increased ROS in the lungs of newborn rats exposed to 60% O(2) for 14 d was likely to be caused, in significant part, by the presence of increased numbers of macrophages.
研究发现，新生大鼠暴露于60%氧气环境14天后，其肺组织对氰化物不敏感的氧气消耗量大幅增加，这反映了活性氧（ROS）生成增加。已知肺组织暴露于高氧环境会增加线粒体ROS的产生。我们推测巨噬细胞可能也是导致这种增加的主要因素。将新生大鼠幼崽暴露于空气或60%氧气环境14天，并分别腹腔注射氯化钆（GdCl₃）以消除巨噬细胞流入，或注射惰性载体。将肺匀浆置于21%或100%氧气环境中平衡，通过极谱法测量总氧气消耗量和对氰化物不敏感的氧气消耗量，以及一氧化氮的积累量。通过蛋白质印迹法对线粒体质量标志物柠檬酸合酶和过氧亚硝酸盐形成标志物硝基酪氨酸进行定量分析。除了巨噬细胞数量增加外，暴露于60%氧气环境的动物肺组织中对氰化物不敏感的氧气消耗量（与空气对照组相比，p<.05）和免疫反应性硝基酪氨酸（p<.05）均大幅增加，而这些均被GdCl₃处理完全消除。暴露于6%氧气环境14天对不依赖过氧亚硝酸盐的一氧化氮释放或线粒体质量没有影响。我们得出结论，新生大鼠暴露于60%氧气环境14天后肺组织中ROS增加很可能在很大程度上是由于巨噬细胞数量增加所致。
