Kretschmer Sarah, Pieper Mario, Klinger Antje, Hüttmann Gereon, König Peter
Institute of Anatomy, Center for Structural and Cell Biology in Medicine, University of Lübeck, Lübeck, Germany.
Institute of Anatomy, Center for Structural and Cell Biology in Medicine, University of Lübeck, Lübeck, Germany; Airway Research Center North, German Center for Lung Research (DZL), Lübeck, Germany.
Am J Pathol. 2017 Nov;187(11):2451-2460. doi: 10.1016/j.ajpath.2017.07.006. Epub 2017 Aug 18.
Integrity of the airway epithelium is essential for normal lung function. However, studies analyzing the repair process of small epithelial lesions in pseudostratified airway epithelium are missing. To follow airway-epithelial wound closure over time, we lesioned small areas of the mouse tracheal epithelium (1 to 12 cells) using a femtosecond laser and followed wound closure up to 6 hours by autofluorescence multiphoton microscopy. Selected lesions were also examined by scanning and transmission electron microscopy and by staining of filamentous actin. Most lesions with a size up to six cells closed by elongation of the surrounding epithelial cells within 6 hours, and all damaged cells were extruded from the epithelium. Electron microscopy confirmed that the surrounding epithelial cells directly closed lesions up to six cells. Most lesions larger than six cells did not close in the observation period of 6 hours, but we observed that basal cells flattened to cover the basement membrane. Delayed wound closure was, in part, attributable to damage of the basement membrane. Cells facing the lesion exhibited increased filamentous actin staining, indicating active cell movement. Not all cells initially facing the lesion participated directly in wound closure, indicating that closure is driven by movement of individual cells rather than a transepithelial coordinated process. Small wounds in the pseudostratified airway epithelium close within hours to preserve epithelial integrity.
气道上皮的完整性对于正常肺功能至关重要。然而，目前尚缺乏分析假复层气道上皮中小上皮损伤修复过程的研究。为了跟踪气道上皮伤口随时间的闭合情况，我们使用飞秒激光对小鼠气管上皮的小区域（1至12个细胞）造成损伤，并通过自发荧光多光子显微镜观察伤口闭合长达6小时的情况。还通过扫描电子显微镜、透射电子显微镜以及丝状肌动蛋白染色对选定的损伤进行了检查。大多数大小达六个细胞的损伤在6小时内通过周围上皮细胞的伸长而闭合，所有受损细胞均从上皮中挤出。电子显微镜证实，周围上皮细胞直接闭合了大小达六个细胞的损伤。大多数大于六个细胞的损伤在6小时的观察期内未闭合，但我们观察到基底细胞扁平以覆盖基底膜。伤口闭合延迟部分归因于基底膜的损伤。面对损伤的细胞表现出丝状肌动蛋白染色增加，表明细胞有活跃的运动。并非所有最初面对损伤的细胞都直接参与伤口闭合，这表明闭合是由单个细胞的运动驱动的，而不是跨上皮的协调过程。假复层气道上皮中的小伤口在数小时内闭合以保持上皮的完整性。
