早产新生儿肺表面活性物质合成水平与呼吸窘迫综合征的关系

Respiratory distress syndrome caused by deficiency of pulmonary surfactant in premature infants

目的探讨早产新生儿肺表面活性物质(pulmonary surfactant,PS)的合成水平,及其与新生儿呼吸窘迫综合症(neonatal respiratory distress syndrome,NRDS)的关系。方法以该院35例早产新生儿(胎龄26～31周)为研究对象,均表现为明显的NRDS症状,需要行气管插管。在此期间,收集患儿气管插管中的气管吸出物,直至第8周为止;另以其他术中需行气管插管的新生儿作为正常对照。对各组样品的总蛋白质含量进行定量检测;并且用免疫印迹法,在各个时间点,对表面活性物质蛋白(surfactant protein,SP)-A,SP-B和SP-C表达水平的改变做半定量分析。结果35例患有NRDS的早产新生儿,在出生1周以内,其气管吸出物中PS的各种组分,如SP-A,SP-B和SP-C的水平都显著低于正常新生儿(P<0.01)。其中,SP-A和SP-B的水平在早产新生儿出生后的2周内开始逐步上升;而SP-C的水平则从第3周开始才显示上升的趋势。结论NRDS的发生主要和PS的低水平表达有明显的相关性。在研究的3种PS组分中,SP-C水平的改善与症状缓解的关系最为密切,它的缺乏可能对NRDS的发生有决定作用。

[Objective] To determine the synthesis level of pulmonary suffaetant in premature infants and its relationship with neonatal respiratory distress syndrome. [Methods] Thirty-five premature infants of 23-31 weeks of gestation requiring intubation for respiratory support were enrolled for this study. Tracheal aspirate samples were colleered from the infants at variant time point weekly until extubation at the 8th week. Control samples were also colleeted from other newborn term infants without lung disease who were intubated for surgieal procedures. Total protein composition in the samples was measured by the Bradford assay and the production and alteration of the Surfaetant Protein-A, -B, and -C was analyzed by using Western Blot. [Results] Among these 35 premature infants with NDRS, all the eontents of PS in their traeheal aspirate samples were signitieantly lower than those in the controls from term infants. The major postnatal inereases for SP-A and SP-B oeeurred during the 2nd weeks and SP-C reaehed plateau values till the 3rd weeks. [Conclusion] Both surfaetant defieieney and dysfunetion may eause NRDS in premature infants. They uniformly have low eoneentrations of SPs, espeeially the SP-C.