Jobe A H, Ikegami M, Seidner S R, Pettenazzo A, Ruffini L
Department of Pediatrics, Harbor-UCLA Medical Center, UCLA School of Medicine, Torrance.
Am Rev Respir Dis. 1989 Feb;139(2):352-9. doi: 10.1164/ajrccm/139.2.352.
Preterm lambs were delivered at 138 days gestational age and ventilated for periods up to 24 h in order to study surfactant metabolism and surfactant function. The surfactant-saturated phosphatidylcholine pool in the alveolar wash was 13 +/- 4 mumol/kg and did not change from 10 min to 24 h after birth. Trace amounts of labeled natural sheep surfactant were mixed with fetal lung fluid at birth. By 24 h, 80% of the label had become lung-tissue-associated, yet there was no loss of label from phosphatidylcholine in the lungs when calculated as the sum of the lung tissue plus alveolar wash. De novo synthesized phosphatidylcholine was labeled with choline given by intravascular injection at 1 h of age. Labeled phosphatidylcholine accumulated in the lung tissue linearly to 24 h, and the labeled phosphatidylcholine moved through lamellar body to alveolar pools. The turnover time for alveolar phosphatidylcholine was estimated to be about 13 h, indicating an active metabolic pool. A less surface-active surfactant fraction recovered as a supernatant after centrifugation of the alveolar washes at 40,000 x g increased from birth to 10 min of ventilation, but no subsequent changes in the distribution of surfactant phosphatidylcholine in surfactant fractions occurred. The results were consistent with recycling pathway(s) that maintained surface-active surfactant pools in preterm ventilated lambs.
早产羔羊在妊娠138天时出生，并进行长达24小时的通气，以研究表面活性剂代谢和表面活性剂功能。肺泡灌洗中表面活性剂饱和的磷脂酰胆碱池为13±4μmol/kg，出生后10分钟至24小时没有变化。出生时将微量标记的天然绵羊表面活性剂与胎儿肺液混合。到24小时时，80%的标记物已与肺组织结合，但按肺组织加肺泡灌洗的总和计算，肺中磷脂酰胆碱的标记物没有损失。新生合成的磷脂酰胆碱在1小时龄时通过血管内注射给予的胆碱进行标记。标记的磷脂酰胆碱在肺组织中线性积累至24小时，并且标记的磷脂酰胆碱从板层体转移至肺泡池。肺泡磷脂酰胆碱的周转时间估计约为13小时，表明存在一个活跃的代谢池。在40,000×g离心肺泡灌洗液后作为上清液回收的表面活性较低的表面活性剂部分从出生到通气10分钟增加，但表面活性剂磷脂酰胆碱在表面活性剂部分中的分布随后没有变化。结果与维持早产通气羔羊中表面活性表面活性剂池的循环途径一致。
