吸氧对新生鼠肺的影响及机制的探讨

Effects and mechanisms of high concentration oxygen inhalation on lung of newborn rats

目的 :模拟早产儿的吸氧状态 ,通过对高氧环境下新生鼠肺的病理及生化指标变化的观察 ,探讨吸高浓度氧对肺的影响及机制。方法 :将新生鼠放入浓度 6 0 %氧的吸氧箱中连续饲养 7d ,以空气中的同日龄鼠为对照组 ,分别检测 1 ,4 ,7d龄鼠的动脉血氧分压 (PaO2 )及肺组织超氧化物歧化酶 (SOD)、丙二醛 (MDA)、一氧化氮(NO)、一氧化氮合酶 (NOS)水平 ,并HE染色观测肺组织病理改变。结果 :实验组 1 ,4 ,7d龄鼠PaO2 高于对照组(P <0 .0 5 ) ,SOD浓度低于相应的对照组 (P <0 .0 5 ,P<0 0 1 ) ,MDA ,NO ,NOS的浓度均高于相应的对照组 (P<0 0 5或P <0 0 1 )。病理改变 :实验组 4d龄鼠见肺泡内少量红细胞渗出 ,部分肺泡间隔增厚 ,7日龄鼠见肺泡间隔进一步增厚 ,间隔内出血 ,有炎性细胞浸润 ,部分肺泡融合。对照组均无异常所见。结论 :高氧环境下可产生过多的超氧自由基 。

Objective: To observe the pathologic and biochemical changes of lung by mimicking the status of premature newborn in high concentrated oxygen and to discuss the effects and mechanisms of oxygen inhalation on the lung. Methods: Newborn rats were put into the oxygen box with the oxygen concentration of 60% continuously for 1,4, and 7 days separately. Rats born at the same time which were fed in air condition served as control. Arterial blood gas analysis including, superoxide dismutase(SOD), malondialdehyde(MDA), nitric oxide(NO), and NO synthase (NOS) of kidney were meatured. The lung was observed by using HE staining. Results: The arterial partial pressure of oxygen in the 3 experimental groups were all significantly higher than that in control (P<0.05), SOD was significantly lower than that in control (P<0.05 ),and MDA was significantly higher than that in control (P<0.05, P<0.01, P<0.01). Both NO and NOS were significantly higher in experimatal group than those in control (NO: P<0.05,P<0.01,P<0.05; NOS: P<0.05). The lung in 1 day old rats of experimental group showed no obvious pathologic change. While in the 4 day old rats, few red blood cell exudated in the alveoli and the septum thickened which were developed more obvious in the 7 day old rats with bleeding in the septum, inflammatory cell infiltrated and even alveoli fusion. No change was found in the control group. Conclusion: Superoxide free radical may play an important role in the mechanisms of pulmonary damage during high concentration oxygen supplying.