Flaxseed Lignan Complex (FLC) Enriched in Secoisolariciresinol Diglucoside (SDG) Prolongs Survival And Protects Against Radiation‐Induced Pneumonopathy In Mice

Abstract

Background Flaxseed (FS), has potent anti-inflammatory and anti-oxidant properties in mouse models of acute and chronic lung injury. It is not known, however, which bioactive ingredient contributes to the protective effects. In this study we tested the lignan component of FS (FLC) consisting mainly of SDG formulated in rodent chow in a murine model of thoracic-radiation induced lung injury. Methods Mice (n=20 per group) were fed an isocaloric control diet or 0.33% or 0.66% FLC corresponding to the lignan content in 10% and 20% wholegrain FS, respectively for 3 weeks. Mice were exposed to a single fraction of 13.5 Gy X-ray thoracic radiation (XRT). Mouse survival, lung inflammation and injury were evaluated 4 months post-XRT in bronchoalveolar lavage. Results Survival increased dose-dependently with FLC diet content (100%, 90% and 44% survival in 0.66%, 0.33% and 0% FLC diets, respectively. Wasting due to radiation also decreased with higher FLC content (12%, 15%, 27% weight loss in 0.66%, 0.33% and 0% FLC). Lung inflammation and injury were also abrogated dose-dependently to levels comparable to those of the wholegrain FS diet. Conclusion The lignan component of FS, mainly consisting of SDG, is protective against radiation pneumonitis in vivo. Funded by: NIH-R01 CA133470-03, NIH-RC1AI081251-01 and the American Institute for Cancer Research #AICR-03B024 (MCS).