Tschumperlin D J, Margulies S S
Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Am J Physiol. 1998 Dec;275(6):L1173-83. doi: 10.1152/ajplung.1998.275.6.L1173.
Deformation of the alveolar epithelial basement membrane with lung inflation has been implicated in blood-gas barrier breakdown during the development of ventilator-induced lung injury. To determine the vulnerability of alveolar epithelial cells to deformation-induced injury, we developed a cell-stretching device that subjects cells to cyclic, equibiaxial strains. Alveolar epithelial type II cells from primary culture were tested 1 and 5 days after seeding, during which time the cells underwent major morphological and phenotypic changes. Cells were subjected to changes in surface area of 12, 24, 37, and 50%, which corresponded to lung inflation of approximately 60, 80, 100, and >100% of total lung capacity. Deformation-induced injury of alveolar epithelial cells, assessed with a fluorescent cell viability assay, increased with deformation magnitude and decreased with time elapsed after seeding. In cells stretched after 1 day in culture, the percentage of dead cells after a single deformation ranged from 0.5 to 72% over the range of deformations used. In cells stretched at 5 days, the percentage of dead cells ranged from 0 to 9% when exposed to identical deformation protocols. These results suggest that morphological and phenotypic changes with time in culture fundamentally change the vulnerability of alveolar epithelial cells to deformation.
肺泡上皮基底膜随肺膨胀发生变形，这与呼吸机诱导的肺损伤发展过程中的血气屏障破坏有关。为了确定肺泡上皮细胞对变形诱导损伤的易感性，我们开发了一种细胞拉伸装置，使细胞受到周期性等双轴应变。对原代培养的肺泡II型上皮细胞在接种后1天和5天进行测试，在此期间细胞经历了主要的形态和表型变化。使细胞表面积分别改变12%、24%、37%和50%，这分别对应于约60%、80%、100%和超过100%肺总量的肺膨胀。用荧光细胞活力测定法评估，肺泡上皮细胞的变形诱导损伤随变形幅度增加而增加，随接种后经过的时间而减少。在培养1天后拉伸的细胞中，在所用变形范围内，单次变形后死细胞的百分比在0.5%至72%之间。在5天时拉伸的细胞中，当暴露于相同的变形方案时，死细胞的百分比在0%至9%之间。这些结果表明，培养过程中随时间发生的形态和表型变化从根本上改变了肺泡上皮细胞对变形的易感性。
