一氧化氮合成酶在不同压力氧气导致的肺型氧中毒中的表达变化

目的：临床上过量使用氧气可导致肺型氧中毒的发生，目前有文献认为常压氧和高压氧导致的肺型氧中毒具有不同的发病机制。本实验拟探讨一氧化氮合成酶在不同压力氧气导致的肺型氧中毒中的表达变化。方法：60只雄性SD大鼠，随机分为6组（n=10），分别暴露于1绝对压（atmosphere absolute，ATA）、1．5ATA、2ATA、2．5ATA、3ATA，100％氧气中56、20、10、8、6h，暴露于空气组作为对照。出舱后测定各组大鼠肺组织湿干比、支气管肺泡灌洗液蛋白含量。收集肺组织，裂解提取蛋白。行Western blot检测内皮一氧化氮合酶（eNOS）、神经型一氧化氮合酶（eNOS）的表达变化。结果：相对于正常对照组，1．0ATA组肺湿干比、支气管肺泡灌洗液蛋白量表达明显增高。随着氧分压的增高，这种改变减弱。和1．0ATA组相比，高压氧组的肺湿干比、肺泡灌洗液蛋白含量显著降低。各个氧气压力暴露组大鼠肺组织中nNOS的含量没有明显改变。而eNOS含量则在氧气压力为2ATA时明显降低（P〈0．05），氧气压力为2．5ATA及3ATA时明显增高（P〈0．05）。结论：eNOS在肺中的表达量随着氧气压力的变化而改变。

The change of NOS in pulmonary oxygen toxicity induced by hiffereut oxygen pressure

Objective： Long time exhaled oxygen will induced oxygen toxicity. Some studies had found that different pathology may exised in normobaric and hyperbaric pulmonary oxygen toxicity, and nitric oxide synthase（NOS） may play a role. In this study, we discussed the change of NOS in normobaric and hyperbaric pulmonary oxygen toxicity. Methods： Sixty male SD rats were randomly divided into 6 groups（ n = 10）, exposed to 1 ATA （atmosphere absolute）, 1.5 ATA, 2 ATA, 2.5 ATA and 3 ATA, 100% oxygen for 56,20,10,8,6 hours respectively. Rats were exposed to air as control. After exposure, the protein in bronchoalveolar lavage fluid （BALF）, the wet/dry weight of lung and the expression of eNOS,nNOS in lung were defined. Results： As compared to air group, the protein in BALF, the wet/dry of lung were significantly elevated in 1.0 ATA group, while these changes were not so obviously in the other groups, and these changes in hyperbaric oxygen group （ - 1.0 ATA） were significantly decreased as compared with normobaric oxygen group （1.0 ATA）. The expression of nNOS were not changed in normobaric and hyperbaric pulmonary oxygen toxicity, while the expression of eNOS was significantly decreased in 2 ATA group, and significantly elevated in 2.5 ATA and 3 ATA group. Conclusion： The expression of eNOS can change when exposed to different pressures of oxygen.