Gehr P, Geiser M, Im Hof V, Schürch S, Waber U, Baumann M
Department of Anatomy, University of Berne, Switzerland.
Microsc Res Tech. 1993 Dec 1;26(5):423-36. doi: 10.1002/jemt.1070260510.
We have investigated the displacement into the sol phase of inhaled particles deposited in the intrapulmonary conducting airways. Hamsters inhaled an aerosol of monodisperse polystyrene particles of 6 microns diameter. Their lungs were fixed by intravascular perfusion, and light and electron microscopy was used to study the epithelial coating. The surfactant film at the wall-air interface was investigated by measuring its surface tension. The number of particles retained was determined stereologically. In addition we investigated the displacement of spherical particles in vitro on a DPPC monolayer in a Langmuir-Wilhelmy surface balance and determined the surface tension in vivo in the horse trachea by video bronchoscopy, applying the droplet spreading method. We found that particles deposited onto a surfactant film were pulled into the aqueous subphase, and we concluded that surface forces due to the airway surfactant likely displace deposited particles into the periciliary fluid (sol phase). Comparing lungs fixed immediately after inhalation with lungs fixed 24 hr after inhalation revealed that 86% of the particles retained in the intrapulmonary conducting airways immediately after inhalation had been cleared within 24 hr. One-third of the particles of the lungs fixed immediately after inhalation was phagocytized. The combination of structural and stereological analyses with in vitro and in vivo measurements has led to new insights into the role of airway surfactant with respect to the fate of inhaled particles, which may have important consequences regarding the effects of hazardous particles. These studies may also help to evaluate the deposition pattern and clearance of therapeutic particles, with important implications for their therapeutic use.
我们研究了沉积在肺内传导气道中的吸入颗粒向溶胶相的位移情况。仓鼠吸入直径为6微米的单分散聚苯乙烯颗粒气溶胶。通过血管内灌注固定它们的肺部，并使用光学显微镜和电子显微镜研究上皮覆盖物。通过测量其表面张力来研究壁-气界面处的表面活性剂膜。采用体视学方法确定保留的颗粒数量。此外，我们在体外使用Langmuir-Wilhelmy表面天平研究了球形颗粒在二棕榈酰磷脂酰胆碱（DPPC）单层上的位移情况，并通过视频支气管镜应用液滴铺展法测定了马气管内的体内表面张力。我们发现沉积在表面活性剂膜上的颗粒被拉入水相亚层，并且我们得出结论，气道表面活性剂产生的表面力可能会将沉积的颗粒位移到纤毛周液（溶胶相）中。比较吸入后立即固定的肺部与吸入后24小时固定的肺部发现，吸入后立即保留在肺内传导气道中的颗粒有86%在24小时内被清除。吸入后立即固定的肺部中有三分之一的颗粒被吞噬。结构分析和体视学分析与体外和体内测量相结合，使我们对气道表面活性剂在吸入颗粒命运方面的作用有了新的认识，这可能对有害颗粒的影响产生重要后果。这些研究也可能有助于评估治疗性颗粒的沉积模式和清除情况，对其治疗应用具有重要意义。
