Modeling radiation-induced lung injury: lessons learned from whole thorax irradiation

Abstract

Models of thoracic irradiation have been developed as clinicians and scientists have attempted to decipher the events that led up to the pulmonary toxicity seen in human subjects following radiation treatment. The most common model is that of whole thorax irradiation (WTI), applied in a single dose. Mice, particularly the C57BL/6J strain, has been frequently used in these investigations, and has greatly informed our current understanding of the initiation and progression of radiation-induced lung injury (RILI). In this review, we highlight the sequential progression and dynamic nature of RILI, focusing primarily on the vast array of information that has been gleaned from the murine model. Ample evidence indicates a wide array of biological responses that can be seen following irradiation, including DNA damage, oxidative stress, cellular senescence and inflammation, all triggered by the initial exposure to ionizing radiation (IR) and heterogeneously maintained throughout the temporal progression of injury, which manifests as acute pneumonitis and later fibrosis. It appears that the early responses of specific cell types may promote further injury, disrupting the microenvironment and preventing a return to homeostasis, although the exact mechanisms driving these responses remains somewhat unclear. Attempts to either prevent or treat RILI in preclinical models have shown some success by targeting these disparate radiobiological processes. As our understanding of the dynamic cellular responses to radiation improves through the use of such models, so does the likelihood of preventing or treating RILI.

Keywords:

• Whole thorax irradiation
• radiation-induced lung injury
• pneumonitis
• fibrosis
• murine model

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the following National Institutes of Health [grant number: T32HL066988] Multidisciplinary Training in Pulmonary Research Award.

Notes on contributors

Tyler A. Beach

Tyler A. Beach is a member of the University of Rochester School of Medicine and Dentistry, Department of Environmental Medicine.

Angela M. Groves

Angela M. Groves is a member of the Department of Pediatrics and Neonatology at the University of Rochester School of Medicine and Dentistry.

Jacqueline P. Williams

Jacqueline P. Williams is a member of the University of Rochester School of Medicine and Dentistry, Department of Environmental Medicine.

Jacob N. Finkelstein

Jacob N. Finkelstein is a member of the University of Rochester School of Medicine and Dentistry, Department of Environmental Medicine.