Mouse Strain Modulates the Role of the Ciliated Cell in Acute Tracheobronchial Airway Injury-Distal Airways

Understanding cellular repair mechanisms in vivo has been advanced through the use of well-defined injury and repair models and their application to knockout and transgenic animals, primarily mice generated in a variety of background strains. However, little is known concerning the effect that mouse strain itself has on the interpretation and comparability of observations when the strain used for genetic manipulation is not the strain used to develop the model. We compared acute bronchiolar injury and repair in three strains of mice used in knockout mouse development (C57BL/6, 129/TerSv, and 129/SvEv) to the model strain (Swiss Webster) after treatment with the same dose of naphthalene and sacrificed at 1, 2, 4, 7, and 14 days after treatment. Extent of Clara cell toxicity and exfoliation was identical in the distal airways of all strains. There were significant strain-related differences in ciliated cell squamation, initiation and duration of proliferation, epithelial differentiation, and time to completion of epithelial repair. We conclude that ciliated cells play a prominent role in repair of distal airway injury, but that all phases of the repair process differ by strain. In addition, our findings reinforce that control animals must be of the same strain, ideally litter mates, when transgenic or knockout mice are used for the study of airway repair processes and mechanisms.