一氧化氮及一氧化氮合酶在急性吸入高浓度氧大鼠肺泡上皮细胞凋亡中的作用

摘要

AIM:To study the effect of nitric oxide/nitric oxide synthase( NO/NOS ) on apoptosis of rat alveolar epithelial cells induced by acute high - concentration oxygen inhalation. METHODS:Healthy Wistar rats were randomly divided into 5 groups ( half male and half female, n = 12 each ); air control group, 4 h group, 8 h group, 12 h group and 16 h group. The rats were exposed to 85% - 100% oxygen in a self - made chamber for different time periods and the rats in control group were kept in normal room air ( 21 % oxygen ). The levels of malondialdehyde( MDA ), NO and NOS in plasma and lung tissues were detected. The protein expression of eNOS and iNOS in the lung were measured by Western blotting. The apoptosis of alveolar epithelial cells was determined using TUNEL technique. RESULTS: Compared with control group, the levels of MDA, NO and NOS in plasma and lung tissues markedly increased in all hyperoxia groups ( P <0. 01 ). The protein expression of eNOS was clear in control group, increased at 4 h, and obviously increased at 8 h, 12 h and 16 h after hyperoxia exposure. The protein expression of iNOS was far lower than that of eNOS in control group, and slightly increased at 16th h. The number of apoptosis cells increased by 9. 13% ±3.20%, 17.47% ±3.50%, 19.22% ± 4. 50% and 11. 03% ±2. 80% at4h,8h, 12 h and 16 h after exposed to high - concentration oxygen, respectively, compared with control group. The indexes in plasma and lung tissues and the number of cell apoptosis had significant positive correlations. CONCLUSION: NO/NOS may play a very important role in the apoptosis of rat alveolar epithelial cells exposed to hyperoxia.%目的:观察一氧化氮及其合酶在急性吸入高浓度氧大鼠肺泡上皮细胞凋亡中的作用.方法:60只大鼠随机分为空气对照组(21%O2)和高氧实验组4 h组、8 h 组、12 h组和16 h组(85%～100%O2),每组12只,雌雄各半.比色法测定血浆、肺组织匀浆中丙二醛(MDA)、一氧化氮(NO)和一氧化氮合酶(NOS)活性.Western blotting检测肺组织中eNOS和iNOS蛋白表达.采用TUNEL染色法检测肺泡表面凋亡细胞,HE染色观察肺组织病理改变.结果:与对照组比较,高氧各时相组血浆及肺组织匀浆MDA、NO、NOS均升高,差异显著(P＜0.01).对照组eNOS明显表达,高氧4 h组表达开始升高,8 h组eNOS蛋白质表达升高明显.对照组iNOS蛋白微量表达,但表达量远低于eNOS,16 h组表达略增强.与对照组(2.17%±1.80%)比较,4 h组肺泡上皮细胞凋亡数量增加9.13%±3.20%,8 h组、12 h组及16 h组凋亡细胞的数量增加达17.47%±3.50%、19.22%±4.50%和11.03%±2.80%.高氧各组血浆及肺组织各指标与细胞凋亡呈明显的正相关.结论:NO及eNOS在急性高氧诱导的肺泡上皮细胞凋亡的过程中可能发挥介导作用.