Senescence gene signature of radiation fibrosis

Radiation lung injury is characterized by early inflammation and late fibrosis. The causes underlying the chronic, progressive nature of radiation injury are poorly understood. Here, we report that the gene expression of irradiated lung tissue correlates with that observed in the lungs in aged animals. We demonstrate that NOX4 expression and superoxide elaboration is increased in irradiated lungs and pneumocytes in a dose dependent fashion. We used microarrays to detail the global programme of gene expression and report that irradiated lung tissue correlates with that observed in the lungs in aged animals. Female C57Bl/Ncr mice, aged 10 weeks were treated with/ without radiation to the thorax with a X-RAD 320 x-ray irradiator at a dose rate of 2.61 Gy/minute. An age-matched cohort of mice received no IR while additional cohorts received 5 Gy in a single dose, 17.5 Gy in a single dose. RNA was extracted and hybridization done on Affymetrix Mouse430_2 microarrays.