319. Int J Radiat Oncol Biol Phys. 2001 Jul 15;50(4):851-5.
Radiation-induced hypoxia may perpetuate late normal tissue injury.
Vujaskovic Z(1), Anscher MS, Feng QF, Rabbani ZN, Amin K, Samulski TS, Dewhirst
MW, Haroon ZA.
Author information:
(1)Department of Radiation Oncology, Duke University Medical Center, Durham, NC
27710, USA. vujas@radonc.duke.edu
PURPOSE: The purpose of this study was to determine whether or not hypoxia
develops in rat lung tissue after radiation.
METHODS AND MATERIALS: Fisher-344 rats were irradiated to the right hemithorax
using a single dose of 28 Gy. Pulmonary function was assessed by measuring the
changes in respiratory rate every 2 weeks, for 6 months after irradiation. The
hypoxia marker was administered 3 h before euthanasia. The tissues were harvested
at 6 weeks and 6 months after irradiation and processed for immunohistochemistry.
RESULTS: A moderate hypoxia was detected in the rat lungs at 6 weeks after
irradiation, before the onset of functional or histopathologic changes. The more
severe hypoxia, that developed at the later time points (6 months) after
irradiation, was associated with a significant increase in macrophage activity,
collagen deposition, lung fibrosis, and elevation in the respiratory rate.
Immunohistochemistry studies revealed an increase in TGF-beta, VEGF, and CD-31
endothelial cell marker, suggesting a hypoxia-mediated activation of the
profibrinogenic and proangiogenic pathways.
CONCLUSION: A new paradigm of radiation-induced lung injury should consider
postradiation hypoxia to be an important contributing factor mediating a
continuous production of a number of inflammatory and fibrogenic cytokines.
PMID: 11429211 [PubMed - indexed for MEDLINE]