油酸肺损伤时肺泡Ⅱ型上皮细胞钠水通道的研究

Aquaporin and Na^+ transport of alveolar type Ⅱcells in rats with oleic acid-induced acute respiratory distress syndrome

目的测定急性呼吸窘迫综合征(ARDS)状态下肺泡Ⅱ型上皮细胞(ATⅡ)上AOPs的表达量以及全细胞钠电流的大小,以评估病理状态下ATⅡ细胞钠水主动转运能力的状况。方法急性分离纯化油酸ARDS模型大鼠的ATⅡ细胞,用免疫细胞化学、免疫电镜以及Westernblotting方法测定AQP1的表达;用膜片钳技术的全细胞模式测定全细胞钠电流并观察应用特布他林对它的影响。结果ARDS模型组ATⅡ细胞免疫细胞化学AQP1呈阳性,免疫电镜结果细胞膜上可见高电子密度阳性反应,Westernblotting分析显示AQP1蛋白条带较对照组明显减弱。全细胞钠电流较对照组明显降低,但对特布他林仍旧敏感。结论ARDS状态下,ATⅡ细胞的钠水主动转运能力明显受损,但并未完全丧失,钠通道激动剂特布他林可以促进钠的转运。ATⅡ细胞钠水通道在肺水的清除中都起着重要的作用。

Objective To evaluate the capacity of active water and sodium transport of alveolar type Ⅱ （ATⅡ ） cells in rats with acute respiratory distress syndrome （ARDS）. Methods AT II cells were isolated and purified from rats with ARDS, and the distribution of aquaporin-1 （AQP-1） on the cells was observed by immunocytochemistry, immunoelectron microscopy and Western blotting. The sodium currents were detected by patch-clamp technique in whole-cell recording mode. Results Immunocytochemistry showed staining for AQP-1 in rat ATⅡ cells, and immunoelectron microscope demonstrated the presence of AQP-1, which was decreased as shown by Western blotting in comparison with the control group. The whole-cell currents were also decreased, but remained sensitive to terbutalin treatment. Conclusions The capacity of active water and sodium transport is damaged, but not totally lost in ATⅡ cells of ARDS rats. Terbutalin can increase the currents even if in pathological conditions. AOP-1 and sodium transport of ATⅡ cells play an important role in nulmonarv liquid clearance.