Neonatal Research, and.
Department of Paediatrics.
Am J Respir Cell Mol Biol. 2019 Nov;61(5):631-642. doi: 10.1165/rcmb.2019-0084OC.
The development of regional lung injury in the preterm lung is not well understood. This study aimed to characterize time-dependent and regionally specific injury patterns associated with early ventilation of the preterm lung using a mass spectrometry-based proteomic approach. Preterm lambs delivered at 124-127 days gestation received 15 or 90 minutes of mechanical ventilation (positive end-expiratory pressure = 8 cm HO, Vt = 6-8 ml/kg) and were compared with unventilated control lambs. At study completion, lung tissue was taken from standardized nondependent and dependent regions, and assessed for lung injury via histology, quantitative PCR, and proteomic analysis using Orbitrap-mass spectrometry. Ingenuity pathway analysis software was used to identify temporal and region-specific enrichments in pathways and functions. Apoptotic cell numbers were ninefold higher in nondependent lung at 15 and 90 minutes compared with controls, whereas proliferative cells were increased fourfold in the dependent lung at 90 minutes. The relative gene expression of lung injury markers was increased at 90 minutes in nondependent lung and unchanged in gravity-dependent lung. Within the proteome, the number of differentially expressed proteins was fourfold higher in the nondependent lung than the dependent lung. The number of differential proteins increased over time in both lung regions. A total of 95% of enriched canonical pathways and 94% of enriched cellular and molecular functions were identified only in nondependent lung tissue from the 90-minute ventilation group. In conclusion, complex injury pathways are initiated within the preterm lung after 15 minutes of ventilation and amplified by continuing ventilation. Injury development is region specific, with greater alterations within the proteome of nondependent lung.
早产儿肺部区域性肺损伤的发展机制尚未完全明确。本研究旨在采用基于质谱的蛋白质组学方法，描述与早产儿肺早期通气相关的、具有时间依赖性和区域性特征的损伤模式。在妊娠 124-127 天出生的早产羔羊中，给予 15 分钟或 90 分钟的机械通气（呼气末正压=8 厘米水柱，潮气量=6-8 毫升/公斤），并与未通气的对照羔羊进行比较。研究结束时，从标准化的非依赖区和依赖区采集肺组织，通过组织病理学、定量 PCR 和使用轨道阱质谱的蛋白质组分析评估肺损伤。采用 Ingenuity 通路分析软件识别时间和区域特异性通路和功能的富集。与对照组相比，15 分钟和 90 分钟时非依赖区的凋亡细胞数量增加了 9 倍，而 90 分钟时依赖区的增殖细胞数量增加了 4 倍。非依赖肺的肺损伤标志物的相对基因表达在 90 分钟时增加，而重力依赖肺的基因表达不变。在蛋白质组中，非依赖肺的差异表达蛋白数量是非依赖肺的四倍。这两种肺区的差异蛋白数量均随时间增加。在通气 90 分钟的非依赖肺组织中，95%的富集经典通路和 94%的富集细胞和分子功能仅被识别。总之，在通气 15 分钟后，复杂的损伤途径在早产儿肺部开始启动，并在持续通气的情况下放大。损伤的发展是具有区域性特征的，非依赖肺的蛋白质组发生了更大的改变。
