Effects of Thoracic Irradiation on Pulmonary Endothelial Compared to Alveolar Type-II Cells in Fibrosis-Prone C57BL/6NTac Mice

Background/Aim: Thoracic irradiation results in an acute inflammatory response, latent period, and late fibrosis. Little is known about the mechanisms involved in triggering late radiation fibrosis. Materials and Methods: Thoracic irradiated fibrosis prone C57BL/6NTac mice were followed for detectable mRNA transcripts in isolated lung cells and microRNA in whole-tissues, and the effect of administration of water-soluble oxetanyl sulfoxide MMS350 was studied. Marrow stromal cell motility in medium from fibrotic-phase explanted pulmonary endothelial and alveolar type-II cells was measured. Results: RNA and micro-RNA expression in lung correlated with fibrosis. MMS350 reduced pro-fibrotic gene expression in both endothelial and alveolar type-II cells in irradiated mice. Conditioned medium from irradiated cells did not alter cell motility in vitro. Conclusion: These studies should facilitate identification of potential new drug targets for ameliorating irradiation-induced pulmonary fibrosis.