Wang Z, Hall S B, Notter R H
Department of Pediatrics, University of Rochester, NY 14642, USA.
J Lipid Res. 1996 Apr;37(4):790-8.
Surface tension-time adsorption isotherms were measured at 37 degrees C for calf lung surfactant extract (CLSE) and subfractions of its constituents: the complete mix of surfactant phospholipids (PPL), phospholipids depleted in anionic phospholipids (mPPL), hydrophobic surfactant proteins plus phospholipids (SP&PL, SP&mPL), and neutral lipids plus phospholipids (N&PL). Adsorption experiments were done using a static bubble surfactometer where diffusion resistance was present, and in a Teflon dish where diffusion was minimized by subphase stirring. The contribution of diffusion to bubble adsorption measurements decreased as phospholipid concentration increased, and was small at 0.25 mM phospholipid. At this phospholipid concentration, PPL, mPPL, and N&PL all adsorbed more rapidly and to lower final surface tensions than dipalmitoyl phosphatidylcholine (DPPC) on the bubble. However, none of these phospholipid mixtures adsorbed to surface tensions below 46 mN/m after 20 min, behavior that was significantly worse than CLSE, SP&PL, and SP&mPL which additionally contained hydrophobic SP. Both CLSE and SP&PL rapidly adsorbed to surface tensions below 25 mN/m at 0.25 mM phospholipid concentration on the bubble, as did SP&mPL at a somewhat reduced rate. Further experiments defining the influence of hydrophobic protein content showed that addition of even 0.13% SP (by wt) to PPL improved adsorption substantially, and that mixtures of PPL combined with 1% SP had adsorption very similar to CLSE. Mixtures of SP combined with mPPL had faster adsorption than corresponding mixtures of SP:DPPC, and neither fully matched the adsorption rates of CLSE and SP&PL even at high SP levels (4% in SP:mPPL and 5.2% in SP:DPPC). These results demonstrate that although the secondary zwitterionic and anionic phospholipids and neutral lipids in lung surfactant enhance adsorption relative to DPPC, the hydrophobic SP have a much more pronounced effect in promoting the rapid entry of pulmonary surfactant into the air-water interface.
在37℃下测定小牛肺表面活性剂提取物（CLSE）及其成分亚组分的表面张力-时间吸附等温线：表面活性剂磷脂的完整混合物（PPL）、阴离子磷脂耗尽的磷脂（mPPL）、疏水表面活性剂蛋白加磷脂（SP&PL、SP&mPL）以及中性脂质加磷脂（N&PL）。吸附实验在存在扩散阻力的静态气泡表面张力仪中进行，以及在通过亚相搅拌使扩散最小化的聚四氟乙烯培养皿中进行。随着磷脂浓度增加，扩散对气泡吸附测量的贡献降低，在磷脂浓度为0.25 mM时较小。在此磷脂浓度下，PPL、mPPL和N&PL在气泡上的吸附都比二棕榈酰磷脂酰胆碱（DPPC）更快，且最终表面张力更低。然而，20分钟后，这些磷脂混合物均未吸附至低于46 mN/m的表面张力，其表现明显比另外含有疏水SP的CLSE、SP&PL和SP&mPL更差。在气泡上，当磷脂浓度为0.25 mM时，CLSE和SP&PL都能迅速吸附至低于25 mN/m的表面张力，SP&mPL的吸附速率有所降低时也是如此。进一步确定疏水蛋白含量影响的实验表明，向PPL中添加甚至0.13%（重量）的SP可显著改善吸附，并且PPL与1% SP的混合物的吸附与CLSE非常相似。SP与mPPL的混合物的吸附比相应的SP:DPPC混合物更快，即使在高SP水平下（SP:mPPL中为4%，SP:DPPC中为5.2%），两者都不完全匹配CLSE和SP&PL的吸附速率。这些结果表明，尽管肺表面活性剂中的二级两性离子和阴离子磷脂以及中性脂质相对于DPPC可增强吸附，但疏水SP在促进肺表面活性剂快速进入气-水界面方面具有更显著的作用。
