Comprehensive dataset to assess morphological changes subsequent to bleomycin exposure

Intratracheal bleomycin causes pulmonary injury, inflammation and fibrosis. The characteristic patchy nature of the injury makes analysis challenging. Histological assessment of lung injury is a useful tool to evaluate damage, however quantification is not standardized. We propose a multi-factorial approach to assess morphological changes subsequent to intratracheal bleomycin mediated lung injury. Lungs were inflation fixed with paraformaldehyde, sectioned and stained with hematoxylin and eosin. Whole slide images were scanned and ten 400x images were randomly chosen throughout the tissue for further analysis. Using ImageJ software, alveolar wall width was measured, nuclei were counted and airspace was quantified. Morphological changes were identified in mice instilled with bleomycin. This combination offers a robust measure of lung morphology especially in a heterogenous injury.

NADPH Oxidases and Aging Models of Lung Fibrosis

There is a growing recognition that aging is a risk factor for fibrosis that affects a number of organ systems, including the lung. Despite this understanding, most studies of experimental fibrosis have been conducted in young mice that typically resolve injury-induced lung fibrosis over the course of several months. Our studies demonstrate that aged mouse models may recapitulate human disease by generating a more persistent fibrotic response to injury. This is, in part, due to an imbalance in the expression and activity of NADPH oxidase (NOX) enzymes, in particular the NOX4 isoform, and a related deficiency in antioxidant responses in pathogenic myofibroblasts. These pathogenic myofibroblasts acquire features of cellular senescence and become resistant to apoptosis. In this chapter, we present methods and procedures to apply the aging model of lung fibrosis in mice that will allow interrogation of myofibroblast functions and the expression and activity of NOX4 in cells. We provide recommendations for best laboratory practices to assess the severity and resolution of fibrosis in murine models of aging.