Laboratory of Adaptive and Regenerative Biology and Division of Thoracic Surgery, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Institute for Computational and Mathematical Engineering, Department of Management Science & Engineering, Stanford University, Stanford, California, USA.
J Cell Physiol. 2023 Jan;238(1):274-284. doi: 10.1002/jcp.30927. Epub 2022 Dec 11.
Pleural epithelial adaptations to mechanical stress are relevant to both normal lung function and parenchymal lung diseases. Assessing regional differences in mechanical stress, however, has been complicated by the nonlinear stress-strain properties of the lung and the large displacements with ventilation. Moreover, there is no reliable method of isolating pleural epithelium for structural studies. To define the topographic variation in pleural structure, we developed a method of en face harvest of murine pleural epithelium. Silver-stain was used to highlight cell borders and facilitate imaging with light microscopy. Machine learning and watershed segmentation were used to define the cell area and cell perimeter of the isolated pleural epithelial cells. In the deflated lung at residual volume, the pleural epithelial cells were significantly larger in the apex (624 ± 247 μm ) than in basilar regions of the lung (471 ± 119 μm ) (p < 0.001). The distortion of apical epithelial cells was consistent with a vertical gradient of pleural pressures. To assess epithelial changes with inflation, the pleura was studied at total lung capacity. The average epithelial cell area increased 57% and the average perimeter increased 27% between residual volume and total lung capacity. The increase in lung volume was less than half the percent change predicted by uniform or isotropic expansion of the lung. We conclude that the structured analysis of pleural epithelial cells complements studies of pulmonary microstructure and provides useful insights into the regional distribution of mechanical stresses in the lung.
胸膜上皮对机械应力的适应性与正常肺功能和实质肺疾病都有关。然而，评估机械应力的区域差异受到肺的非线性应力-应变特性和通气时的大位移的影响。此外，没有可靠的方法可以将胸膜上皮分离出来进行结构研究。为了定义胸膜结构的拓扑变化，我们开发了一种从鼠胸膜上皮进行正面收获的方法。银染用于突出细胞边界，便于用光学显微镜进行成像。机器学习和分水岭分割用于定义分离的胸膜上皮细胞的细胞面积和细胞周长。在剩余容量时的塌陷肺中，胸膜上皮细胞在肺尖（624±247μm）比在肺基底区域（471±119μm）明显更大（p<0.001）。顶上皮细胞的变形与胸膜压力的垂直梯度一致。为了评估充气时上皮的变化，在肺总量时研究了胸膜。上皮细胞的平均面积增加了 57%，周长增加了 27%，从剩余容量到肺总量。肺容积的增加不到肺均匀或各向同性膨胀预测的变化百分比的一半。我们的结论是，胸膜上皮细胞的结构分析补充了肺微观结构的研究，并为肺中机械应力的区域分布提供了有用的见解。
