大鼠II型肺泡细胞中的离子含量与细胞容积调节

Ionic content and regulation of cellular volume in rat alveolar type II cells.

作者信息

Jones G S, Miles P R, Lantz R C, Hinton D E, Castranova V

出版信息

J Appl Physiol Respir Environ Exerc Physiol. 1982 Jul;53(1):258-66. doi: 10.1152/jappl.1982.53.1.258.

DOI:10.1152/jappl.1982.53.1.258

Abstract

Alveolar type II epithelial cells were isolated by elastase digestion of rat lungs and purified by centrifugal elutriation. This method yields an enriched fraction of 1 x 10(7) cells/rat containing 85% pure type II pneumocytes. Purified type II cells exhibit a high rate of oxygen consumption, 215 nmol O2 . 10(6) cells-1 . h-1, which is unaffected by the addition of succinate. Type II cells contain 2 microliters H2O/10(7) cells and are approximately 325-330 micrometers 3 in volume. These pneumocytes contain 107 nmol K/l cell H2O and 70 mmol Cl/l cell H2O. In addition, type II cells have a high Na content, i.e., 156 mmol/l cell H2O. However, most of this Na is bound with only 33% being exchangeable. Therefore, the cytoplasmic concentration of free Na is 51 mmol/l cell H2O. Na uptake is very rapid and type II cells i.e., specific activity equilibrium is reached in 15 min with a half time of 5 min. In addition to this large passive transport of Na, type II cells exhibit a highly active Na-K pump involved in the regulation of cellular volume. Volume regulation is inhibited by a decrease in temperature (2 degrees C) and by the addition of ouabain (10(-4) M), Hg (10(-5) M), or Cu (10(-3) M).

摘要

通过用弹性蛋白酶消化大鼠肺脏来分离肺泡II型上皮细胞，并通过离心淘析进行纯化。该方法可得到每只大鼠1×10⁷个细胞的富集部分，其中含85%的纯II型肺细胞。纯化后的II型细胞表现出较高的耗氧率，即215 nmol O₂·10⁶个细胞⁻¹·h⁻¹，添加琥珀酸对此无影响。II型细胞每10⁷个细胞含有2微升H₂O，体积约为325 - 330立方微米。这些肺细胞每细胞H₂O中含有107 nmol K和70 mmol Cl。此外，II型细胞的Na含量较高，即每细胞H₂O中含156 mmol。然而，其中大部分Na是结合态的，只有33%是可交换的。因此，游离Na的细胞质浓度为每细胞H₂O 51 mmol。Na摄取非常迅速，II型细胞在15分钟内达到比活性平衡，半衰期为5分钟。除了这种大量的Na被动转运外，II型细胞还表现出一种高度活跃的Na - K泵，参与细胞体积的调节。细胞体积调节受到温度降低（2℃）以及添加哇巴因（10⁻⁴ M）、汞（10⁻⁵ M）或铜（10⁻³ M）的抑制。