Highly water-permeable type I alveolar epithelial cells confer high water permeability between the airspace and vasculature in rat lung
Highly water-permeable type I alveolar epithelial cells confer high water permeability between the airspace and vasculature in rat lung
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DOI：
10.1073/pnas.95.6.2991
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发表时间：
1998-03-17
影响因子：
11.1
通讯作者：
Verkman, AS
中科院分区：
文献类型：
--
作者：
Dobbs, LG;Gonzalez, R;Verkman, AS
完整绵羊空气与血管间透水性的测定老鼠的肺高。超过95%的肺内表面由肺泡上皮I型细胞排列。本研究的目的是测试I型肺泡上皮细胞的渗透水通透性（P-f）是否足够高，足以解释完整肺的高P-f，用胸膜表面荧光法测量灌注充满液体的大鼠肺的空气和血管之间的P-f高（0.019 +/- 0.004 cm/s, 12℃）和弱温度依赖性（活化能3.7 kcal/mol）。解决的贡献I型和II型肺泡上皮细胞肺水渗透率,p - stopped-flow光散射测量的纯化I型和II型细胞悬浮液通过immunoaffinity程序,在外部解决方案应对突然的变化从300年到600年同渗重摩mOsm, I型细胞的数量迅速减少,半场(t (1/2)) 60 - 80 ms的10摄氏度,给等离子体膜p / s, 0.06 - -0.08厘米P-f在I型细胞中不受渗透梯度大小的影响，对温度的依赖性较弱（活化能3.4 kcal/mol）。相比之下，II型细胞在悬浮中的t（1/2）要慢得多，接近1 s；II型细胞P-f为0.013 cm/s。来自I型细胞的囊泡在10℃时的P-f也很高，为0.06-0.08 cm/s，被HgCl2抑制95%。I型细胞的P-f是所有哺乳动物细胞膜中测量到的最高的，这可能解释了肺的高透水性。
Water permeability measured between the airspace and vasculature in intact sheep a;nd mouse lungs is high. More than 95% of the internal surface area of the lung is lined by alveolar epithelial type I cells. The purpose of this study was to test whether osmotic water permeability (P-f) in type I alveolar epithelial cells is high enough to account for the high P-f of the intact lung, P-f measured between the airspace and vasculature in the perfused fluid-filled rat lung by the pleural surface fluorescence method was high (0.019 +/- 0.004 cm/s st 12 degrees C) and weakly temperature-dependent (activation energy 3.7 kcal/mol). To resolve the contributions of type I and type II alveolar epithelial cells to lung water permeability, P-f was measured by stopped-flow light scattering in suspensions of purified type I or type II cells obtained by immunoaffinity procedures, In response to a sudden change in external solution osmolality from 300 to 600 mOsm, the volume of type I cells decreased rapidly with a half-time (t(1/2)) of 60-80 ms at 10 degrees C, giving a plasma membrane P-f of 0.06-0.08 cm/s, P-f in type I cells was independent of osmotic gradient size and was weakly temperature-dependent (activation energy 3.4 kcal/mol). In contrast, t(1/2) for type II cells in suspension was much slower, approximate to 1 s; P-f for type II cells was 0.013 cm/s. Vesicles derived from type I cells also had a very high P-f of 0.06-0.08 cm/s at 10 degrees C that was inhibited 95% by HgCl2. The P-f in type I cells is the highest measured for any mammalian cell membrane and would account for the high water permeability of the lung.