内毒素血症时肺动脉和胸主动脉内一氧化氮合酶表达的比较

目的 观察内毒素血症时肺动脉和胸主动脉中诱导型一氧化氮合(iNOS)基因和蛋白表达的时间依从性变化。方法 48只Wistar大鼠350－450g，雌雄兼备，随机均分成对照组（C组），3h组，8h组和48h组。对照组腹腔内注射2ml生理盐水，余各实验组腹腔内注射脂多糖（LPS）4mg/kg，溶于2ml生理盐水，分别在LPS腹腔内注射后3h,8h和48h颈椎脱臼法处死大鼠取肺动脉和胸主动脉，RT－PR和Western blot法测定各组肺动脉和胸主动脉中iNOS的mRNA和蛋白表达。结果 LPS注射后大鼠肺动脉中iNOS的mRNA和蛋白表达逐渐上升，8h达到高峰，48h恢复到LPS注射前水平；胸主动脉中iNOS的蛋白表达3h即达峰值，以后逐渐下降，48h恢复到LPS注射前水平。LPS注射后3h和8h大鼠iNOS的mRNA及蛋白表达水平肺动脉比胸主动脉高。结论 内毒素大鼠的肺动脉和胸主动脉中iNOS的mRNA和蛋白的表达呈现时间依从性变化，iNOS的mRNA和蛋白表达峰值胸主动脉早于肺动脉，肺动脉中iNOS的mRNA和蛋白表达程度高于胸主动脉。

The time-course of mRNA and protein expression of inducible nitric oxide synthase in pulmonary artery and thoracic aorta induced by endotoxemia in rats

Objective To investigate the time-course of mRNA and protein expression of inducible nitric oxide synthase (iNOS) in pulmonary artery and thoracic aorta and the difference in mRNA and protein expressions of iNOS between pulmonary artery and thoracic aorta induced by endotoxemia in rats. Methods Forty-eight Wistar rats of both sexes weighing 350-450g were randomly divided into 2 groups: control group in which animals received normal saline intraperitoneally (ip) and were killed 3h later by dislocation of cervical vertebrae (n=12); test groups in which animals were injected intraperitoneally lipopolysaccharide (LP) 4mg-kg-1 in 2ml of normal saline and were killed after 3h ( n = 12), 8h ( n = 12) , and 48h( n = 12) . Chest was opened immediately and pulmonary artery (PA) and descending thoracic aorta ( TA) were removed. mRNA and protein expression of iNOS in PA and TA were measured by RT-PCR and Western blot.Results The mRNA and protein expressions of iNOS in PA peaked at 8h and that in TA at 3h after ip LPS injection. The levels of mRNA and protein expressions of iNOS in both PA and TA returned to control level at 48h after ip LPS injection. The levels of mRNA and protein expressions of iNOS in PA at 3h and 8h after ip LPS injection were significantly higher than those in TA.Conclusion The mRNA and protein expressions of iNOS in PA and TA after LPS injection are time-dependent. The mRNA and protein expressions of iNOS in TA after LPS injection are earlier than those in PA but the level of mRNA and protein expressions of iNOS in PA after LPS injection is higher than that in TA.