Ueda T, Ikegami M, Jobe A H
Department of Pediatrics, Harbor-UCLA Medical Center, University of California Los Angeles School of Medicine, Torrance 90509.
J Appl Physiol (1985). 1994 Jun;76(6):2701-6. doi: 10.1152/jappl.1994.76.6.2701.
Developmental differences in the intrinsic characteristics of surfactant have not been evaluated. Therefore, heavy-subtype surfactant was recovered from alveolar washes of 132-, 139-, and 148-day preterm lambs, 2- to 3-day-old newborn ventilated lambs, and adult sheep. The density of heavy-subtype surfactant and surfactant protein-A-to-saturated phosphatidylcholine ratios increased significantly with developmental age. In contrast, percent conversion from heavy to light surfactant forms was more rapid for surfactant from preterm animals than for surfactant from mature or adult animals. The function of the heavy-subtype surfactant was tested by treating ventilated 27-day gestational age preterm rabbits. The surfactant from the most immature animals was less effective at improving compliance or maintaining lung volumes on deflation than was surfactant from newborn or adult animals. These results demonstrate intrinsic and functional differences in surfactant from developing compared with mature sheep that correlated with the surfactant protein-A-content. The pattern of changes indicates that the preterm animal is at a disadvantage, because the surfactant is intrinsically abnormal relative to that of the adult.
表面活性剂内在特性的发育差异尚未得到评估。因此，从重132天、139天和148天的早产羔羊、2至3日龄通气新生羔羊以及成年绵羊的肺泡灌洗液中回收了重亚型表面活性剂。重亚型表面活性剂的密度以及表面活性剂蛋白A与饱和磷脂酰胆碱的比率随着发育年龄显著增加。相比之下，早产动物的表面活性剂从重表面活性剂形式向轻表面活性剂形式的转化率比成熟或成年动物的表面活性剂更快。通过治疗27天胎龄的通气早产兔来测试重亚型表面活性剂的功能。与新生或成年动物的表面活性剂相比，最不成熟动物的表面活性剂在改善顺应性或在呼气时维持肺容积方面效果较差。这些结果表明，与成熟绵羊相比，发育中绵羊的表面活性剂在内在和功能上存在差异，且与表面活性剂蛋白A的含量相关。变化模式表明早产动物处于劣势，因为其表面活性剂相对于成年动物的表面活性剂在本质上是异常的。
