title: Dietary flaxseed prevents radiation-induced oxidative lung damage, inflammation and fibrosis in a mouse model of thoracic radiation injury.
abstract: Flaxseed (FS) has high contents of omega-3 fatty acids and lignans with antioxidant properties. Its use in preventing thoracic X-ray radiation therapy (XRT)-induced pneumonopathy has never been evaluated. We evaluated FS supplementation given to mice given before and post-XRT. FS-derived lignans, known for their direct antioxidant properties, were evaluated in abrogating ROS generation in cultured endothelial cells following gamma radiation exposure. Mice were fed 10% FS or isocaloric control diet for three weeks and given 13.5 Gy thoracic XRT. Lungs were evaluated at 24 hours for markers of radiation-induced injury, three weeks for acute lung damage (lipid peroxidation, lung edema and inflammation), and at four months for late lung damage (inflammation and fibrosis). FS-Lignans blunted ROS generation in vitro, resulting from radiation in a dose-dependent manner. FS-fed mice had reduced expression of lung injury biomarkers (Bax, p21 and TGF-beta1) at 24 hours following XRT and reduced oxidative lung damage as measured by malondialdehyde (MDA) levels at 3 weeks following XRT. In addition, FS-fed mice had decreased lung fibrosis as determined by hydroxyproline content and decreased inflammatory cell influx into lungs at 4 months post XRT. Importantly, when Lewis lung carcinoma cells were injected systemically in mice, FS dietary supplementation did not appear to protect lung tumors from responding to thoracic XRT. Dietary FS is protective against pulmonary fibrosis, inflammation and oxidative lung damage in a murine model. Moreover, in this model, tumor radioprotection was not observed. FS lignans exhibited potent radiation-induced ROS scavenging action. Taken together, these data suggest that dietary flaxseed may be clinically useful as an agent to increase the therapeutic index of thoracic XRT by increasing the radiation tolerance of lung tissues.
authors.affiliation: Department of Medicine, University of Pennsylvania Medical Center, Philadelphia, 19104, USA.
authors.forename: James C
authors.initials: JC
authors.lastname: Lee
authors.forename: Ryan
authors.initials: R
authors.lastname: Krochak
authors.forename: Aaron
authors.initials: A
authors.lastname: Blouin
authors.forename: Stathis
authors.initials: S
authors.lastname: Kanterakis
authors.forename: Shampa
authors.initials: S
authors.lastname: Chatterjee
authors.forename: Evguenia
authors.initials: E
authors.lastname: Arguiri
authors.forename: Anil
authors.initials: A
authors.lastname: Vachani
authors.forename: Charalambos C
authors.initials: CC
authors.lastname: Solomides
authors.forename: Keith A
authors.initials: KA
authors.lastname: Cengel
authors.forename: Melpo
authors.initials: M
authors.lastname: Christofidou-Solomidou
mesh_terms: D000818:Animals; D004032:Diet; D019587:Dietary Supplements; D019597:Flax / Q000378:metabolism*; D055370:Lung Injury / Q000473:pathology / Q000517:prevention & control*; D051379:Mice; D011658:Pulmonary Fibrosis / Q000473:pathology / Q000517:prevention & control*; D011832:Radiation Injuries / Q000473:pathology / Q000517:prevention & control*; D012639:Seeds / Q000378:metabolism*; D013909:Thorax / Q000473:pathology / Q000528:radiation effects*