高浓度氧对新生鼠肺的影响

Effect of Hyperoxia on Neonatal Rat Lung

目的 探讨持续吸入高浓度氧对新生鼠肺的影响。 方法 足月和早产 SD新生鼠生后持续吸入 85 %氧 ,分别于第 7和 14天测定其肺组织匀浆上清液中超氧化物岐化酶 (SOD)、过氧化氢酶 (CAT)、谷胱甘肽过氧化物酶 (GP)的活力及肺组织羟脯氨酸的含量 ;观察肺组织形态学的改变 ,并与空气组作对照。 结果 (1)抗氧化酶 (AOE)活力 :高氧组第 7、14天足月鼠及早产鼠抗氧化酶活力均高于对照组 (第 14天 CAT除外 ) ,差异有显著意义 (P<0 .0 5 ) ;高氧组足月鼠及早产鼠第 14天 GP活力持续增高 (P<0 .0 5 ) ,SOD和 CAT活力逐渐下降 ,但差异无显著意义 ;早产鼠仅第 7天 GP活力低于足月鼠 (P<0 .0 5 )。(2 )羟脯氨酸含量 :第 14天足月鼠及早产鼠高氧组均高于对照组、并高于第 7天(P<0 .0 0 1) ,早产鼠高于足月鼠 (P<0 .0 5 )。(3)肺组织病理改变 :第 14天早产鼠与足月鼠肺纤维化发生率及程度均高于第 7天 ,早产鼠高于足月鼠 (P<0 .0 0 5 )。 结论 新生鼠吸入高浓度氧时肺 AOE活力增加 ,第 7天时更为显著。肺纤维化发生率及程度随吸氧时间延长而加重 ;早产鼠比足月鼠更易感。肺羟脯氨酸含量的变化与肺纤维化程度的改变完全一致 ,是反映肺纤维化的一个重要指标。

Objective To determine the effect of prolonged hyperoxia on neonatal rat lung. Methods Full term and premature newborn SD rats were continuosly exposed to 85% oxygen or room air 7 and 14 days after birth.The activities of 3 different kinds of antioxidant enzyme (AOE) including superoxide dismutase(SOD), glutathion peroxidase (GP) and catalase (CAT) in supernatant fractions of lung homogenates were assessed after 7 and 14 days of exposure. So was the lung hydroproline content. Results (1)AOE acctivitis: Except CAT activity at 14 days of exposure, others AOE activities in O 2 exposed rat pups were significantly higher than those in air exposed controls (P<0.05). Only GP activity in premature rats was lower than full term rat at 7 days of exposure(P<0.05). (2)Lung hydroproline content:After 14 days of exposure, pulmonary content of hydroproline was increased in O 2 exposed groups compared with control pups, premature pups showing a greater increase than full term pups(P<0.05). (3) Histologic assessment for lung fibrosis In O 2 exposed groups, lung fibrosis was more severe after 14 days of exposure than that of 7 days.Premature rats showed greater severity of septal fibrosis than full term ones (P<0.005). Conclusion Prolonged hyperoxic exposure appears to be leading to an increase of AOE activity and the formation of lung fibrosis in newborn rats. A longer exposure was associated with both greater incidence and severity of lung fibrosis. Premature rats appearing to be more susceptable to O 2 induced damage than full term newborn SD rats.