Surfactant deficiency in rats without a decreased amount of extracellular surfactant.
Surfactant deficiency in rats without a decreased amount of extracellular surfactant.
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大鼠表面活性剂缺乏但细胞外表面活性剂含量不减少。
DOI：
10.1172/jci110909
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Baier,H
中科院分区：
文献类型：
--
作者：
Massaro,D;Clerch,L;Temple,D;Baier,H
无周期性大充气的低容量通气导致肺泡稳定性降低，气道不饱和磷脂酰胆碱（dsc）以1,000 g时沉积的大聚集体积累量增加；这种形式的表面活性剂降低表面张力的速度比1000克上清馏分中的表面活性剂要慢。这些观察结果导致了我们目前的工作，我们测试了这样一个概念，即如果在1,000 g上清部分中发现的表面活性剂的数量减少，那么在气道表面活性剂总量不减少的情况下，肺泡不稳定可能会发生。在静息潮气量范围内，恒温大鼠在持续通气时肺顺应性下降，肺泡-动脉氧梯度变宽，而在高温大鼠（约39℃）中，同样通气但增加周期性叹气。各组气道dsc总量均未减少，但与对照组相比，每组1,000 g上清部分的dsc均较少。在无周期性叹气的低容量通气时，高热大鼠也出现肺泡不稳定和低氧血症。虽然这些大鼠气道dsc的总量减少，但理论上仍有足够的dsc在整个肺泡表面形成一个连续的单分子膜。然而，在1000 g的上清部分中，表面活性剂不足以形成这样的连续膜。这些发现表明，尽管存在正常量的气道表面活性剂，但通气方式和适度高热可能导致肺泡稳定性下降，由此推断，表面活性剂的细胞外形式或状态对肺泡稳定性有重要影响。
Low volume ventilation without periodic large inflations leads to diminished alveolar stability and to the accumulation of increased amounts of airway disaturated phosphatidylcholine (DSPC) in large aggregates that sediment at 1,000 g; surfactant in this form lowers surface tension less rapidly than surfactant present in the 1,000-g supernatant fraction. These observations led to the present work in which we tested the notion that alveolar instability may develop in the presence of an undiminished quantity of total airway surfactant, if the amount of surfactant found in the 1,000-g supernatant fraction is diminished. Pulmonary compliance fell and the alveolar-arterial O2 gradient widened in normothermic rats during constant ventilation in the resting tidal volume range, and, in hyperthermic rats (approximately 39 degrees C) similarly ventilated but with the addition of periodic sighs. The total amount of airway DSPC was undiminished in each group, but in each less DSPC was present in the 1,000-g supernatant fraction compared with controls. Alveolar instability and hypoxemia also developed in hyperthermic rats during low volume ventilation without periodic sighs. Although the total amount of airway DSPC was decreased in these rats, enough remained to theoretically form a continuous monomolecular film over the entire alveolar surface at functional residual capacity; however, there was insufficient surfactant in the 1,000-g supernatant fraction to form such a continuous film. These findings demonstrate that the mode of ventilation, and moderate hyperthermia, may lead to decreased alveolar stability despite the presence of normal amounts of airway surfactant, and, by inference, indicate the extracellular form or state of surfactant has an important effect on alveolar stability.