Visualizing

Lung Physiology in Response to Chemical and Mechanical Assaults

Acute lung injury (ALI) arises from factors as diverse as endotoxin exposure, chemical assault, acute particulate exposures or mechanical impacts, as seen in ventilator induced lung injury (VILI). ALI and VILI studies push the understanding of both fundamental breathing mechanics and general lung physiology to describe how damage occurs in the hopes of mitigating of damage. VILI in particular, is an explosive area of research following the COVID disease outbreak due to the large number of critically ill patients in hospitals requiring ventilation and concomitant increases in clinical VILI occurrences. Recent ALI studies are examining how VILI and subject specific parameters such as obesity or a history of surgical interventions affect outcomes^{1, 2}.

Bleomycin is a glyxopeptide with a clinical oncological use that can generate a fibrotic lung disease phenotype in pre-clinical pulmonary research animal models. While both merits and areas of concern of bleomycin use are known^{3, 4}, the well-defined disease progression after instillation, as well as operational ease of use, contributes to its popularity.

During the initial week following instillation, bleomycin contributes to an acute lung inflammation response³. Krischer et al. employ this response in their most recent paper which examines structural changes in surfactant producing cells and the blood-gas barrier, across six experimental groups of rats. Experimental conditions start with a healthy (H) vs. bleomycin exposure (B) split. These groups are further split into 3 groups each: 2 groups with ventilation using Positive End Expiratory Pressures (PEEPs) of either 1 or 5 cmH2O or where no ventilation is done before data collection.

Krischer et al. are able to show the effect of both bleomycin and VILI damage on the lung through beautiful images of the lungs under each condition (ex. Figure 1).