Programa de Pós-graduação em Biologia Humana e Experimental, Rio de Janeiro, RJ, Brazil.
Free Radic Biol Med. 2012 Dec 1;53(11):1993-2001. doi: 10.1016/j.freeradbiomed.2012.09.015. Epub 2012 Sep 19.
Our aim was to investigate the role of oxidative stress in elastase-induced pulmonary emphysema. C57BL/6 mice were subjected to pancreatic porcine elastase (PPE) instillation (0.05 or 0.5 U per mouse, i.t.) to induce pulmonary emphysema. Lungs were collected on days 7, 14, and 21 after PPE instillation. The control group was sham injected. Also, mice treated with 1% aminoguanidine (AMG) and inducible NO synthase (iNOS) knockout mice received 0.5 U PPE (i.t.), and lungs were analyzed 21 days after. We performed bronchoalveolar lavage, biochemical analyses of oxidative stress, and lung stereology and morphometry assays. Emphysema was observed histologically at 21 days after 0.5 U PPE treatment; tissues from these mice exhibited increased alveolar linear intercept and air-space volume density in comparison with the control group. TNF-α was elevated at 7 and 14 days after 0.5 U PPE treatment, concomitant with a reduction in the IL-10 levels at the same time points. Myeloperoxidase was elevated in all groups treated with 0.5 U PPE. Oxidative stress was observed during early stages of emphysema, with increased nitrite levels and malondialdehyde and superoxide dismutase activity at 7 days after 0.5 U PPE treatment. Glutathione peroxidase activity was increased in all groups treated with 0.5 U PPE. The emphysema was attenuated when iNOS was inhibited using 1% AMG and in iNOS knockout mice. Furthermore, proteolytic stimulation by PPE enhanced the expression of nitrotyrosine and iNOS, whereas the PPE+AMG group showed low expression of iNOS and nitrotyrosine. PPE stimulus also induced endothelial (e) NOS expression, whereas AMG reduced eNOS. Our results suggest that the oxidative and nitrosative stress pathways are triggered by nitric oxide production via iNOS expression in pulmonary emphysema.
我们的目的是研究氧化应激在弹性蛋白酶诱导的肺气肿中的作用。C57BL/6 小鼠接受胰腺猪弹性蛋白酶（PPE）滴注（0.05 或 0.5 U/只，i.t.）以诱导肺气肿。在 PPE 滴注后第 7、14 和 21 天收集肺。对照组接受假注射。此外，用 1%氨基胍（AMG）和诱导型一氧化氮合酶（iNOS）敲除小鼠接受 0.5 U PPE（i.t.），并在 21 天后分析肺部。我们进行了支气管肺泡灌洗、氧化应激的生化分析以及肺立体学和形态计量学测定。在接受 0.5 U PPE 治疗后 21 天观察到肺气肿；与对照组相比，这些小鼠的组织显示肺泡线性截距和空气空间体积密度增加。在接受 0.5 U PPE 治疗后 7 和 14 天，TNF-α 升高，同时在同一时间点 IL-10 水平降低。所有接受 0.5 U PPE 治疗的组中的髓过氧化物酶均升高。在接受 0.5 U PPE 治疗后 7 天，氧化应激发生在肺气肿的早期阶段，一氧化氮水平升高，丙二醛和超氧化物歧化酶活性增加。所有接受 0.5 U PPE 治疗的组中的谷胱甘肽过氧化物酶活性均增加。当使用 1% AMG 抑制 iNOS 或在 iNOS 敲除小鼠中时，肺气肿减轻。此外，PPE 的蛋白水解刺激增强了硝基酪氨酸和 iNOS 的表达，而 PPE+AMG 组显示 iNOS 和硝基酪氨酸的低表达。PPE 刺激还诱导内皮（e）NOS 表达，而 AMG 降低 eNOS。我们的结果表明，氧化和硝化应激途径通过 iNOS 表达在肺气肿中引发一氧化氮的产生。
