高压氧暴露后肺组织自由基含量与组织形态学改变的关系

The relationship between the quantity of free radicals and morphologic alteration of the lung tissue after hyperbaric oxygen exposure

目的 进一步探索高压氧条件下肺组织内自由基量变与组织形态学改变的相互关系。方法 １１２ 只ＳＤ大鼠在３００ ｋＰａ氧压下暴露不同时程后，据Ｗｒｉｇｈｔ法计算出ＵＰＴＤ值作为氧剂量值；用电子自旋共振技术，观察肺组织自由基含量变化水平，并观察肺组织病理和超微结构的变化。结果 肺自由基含量随氧剂量加大而升高，与对照值比，４００ ＵＰＴＤ时升高２４．７２％ （Ｐ＜ ０．０１），６５０ ＵＰＴＤ时升高３２．２４％ （Ｐ＜ ０．０１），８５０ ＵＰＴＤ时升高４７．７８％ （Ｐ＜ ０．０１），１ １００ ＵＰＴＤ时升高３０．３６％ （Ｐ＜ ０．０１）。肺湿、干重比值增加。随氧剂量增加，肺表面活性物质断裂、脱落加重，示踪剂颗粒进入细胞内，板层体、线粒体增大，板层体有不同程度的空化。结论 肺组织受损，尤其是肺表面活性物质的断裂、脱落导致其功能下降，引起肺泡上皮细胞通透性增高，其原因与肺内自由基含量增多有关。

Objective To further investigate the relationship between the quantity of free radicals and morphologic alteration of the lung tissue exposed to different oxygen doses.Methods The changes of free radical contents in the lung were observed in 112 SD rats exposed to different oxygen doses(UPTD) under 300 kPa abs by using the technique of electron spin resonance(ESR); at the same time, optical microscopic and ultrastructural changes of the pulmonary tissue were also examined.Results The free radical contents of the lung were increased along with the increasing oxygen exposure doses. When compared with the control values, the increases were 24 72%( P <0 01) at 400 UPTD, 32 24%( P <0 01) at 650 UPTD, 47 78%( P <0 01) at 850 UPTD and 30 36%( P <0 01) at 1 100 UPTD respectively. The wet/dry weight ratio of pulmonary tissue was also higher than that of the control. With the increase of oxygen exposure doses, there was broken down and aggravated exfoliation of the pulmonary surfactant(PS). And the lamellar bodies were vacuolated to some different extent. Conclusions The injury of lung tissue, particularly the fragmentation of PS and changes of pulmonary endothelial cell membrane permeability, may be related to the increase of free radicals content in it.