Department of Medicine, Pulmonary Allergy and Critical Care Division, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA.
BMC Cancer. 2011 Jun 24;11:269. doi: 10.1186/1471-2407-11-269.
Flaxseed (FS) is a dietary supplement known for its antioxidant and anti-inflammatory properties. Radiation exposure of lung tissues occurs either when given therapeutically to treat intrathoracic malignancies or incidentally, such as in the case of exposure from inhaled radioisotopes released after the detonation of a radiological dispersion devise (RDD). Such exposure is associated with pulmonary inflammation, oxidative tissue damage and irreversible lung fibrosis. We previously reported that dietary FS prevents pneumonopathy in a rodent model of thoracic X-ray radiation therapy (XRT). However, flaxseed's therapeutic usefulness in mitigating radiation effects post-exposure has never been evaluated.
We evaluated the effects of a 10%FS or isocaloric control diet given to mice (C57/BL6) in 2 separate experiments (n = 15-25 mice/group) on 0, 2, 4, 6 weeks post a single dose 13.5 Gy thoracic XRT and compared it to an established radiation-protective diet given preventively, starting at 3 weeks prior to XRT. Lungs were evaluated four months post-XRT for blood oxygenation levels, inflammation and fibrosis.
Irradiated mice fed a 0%FS diet had a 4-month survival rate of 40% as compared to 70-88% survival in irradiated FS-fed mouse groups. Additionally, all irradiated FS-fed mice had decreased fibrosis compared to those fed 0%FS. Lung OH-Proline content ranged from 96.5 ± 7.1 to 110.2 ± 7.7 μg/ml (Mean ± SEM) in all irradiated FS-fed mouse groups, as compared to 138 ± 10.8 μg/ml for mice on 0%FS. Concomitantly, bronchoalveolar lavage (BAL) protein and weight loss associated with radiation cachexia was significantly decreased in all FS-fed groups. Inflammatory cell influx to lungs also decreased significantly except when FS diet was delayed by 4 and 6 weeks post XRT. All FS-fed mice (irradiated or not), maintained a higher blood oxygenation level as compared to mice on 0%FS. Similarly, multiplex cytokine analysis in the BAL fluid revealed a significant decrease of specific inflammatory cytokines in FS-fed mice.
Dietary FS given post-XRT mitigates radiation effects by decreasing pulmonary fibrosis, inflammation, cytokine secretion and lung damage while enhancing mouse survival. Dietary supplementation of FS may be a useful adjuvant treatment mitigating adverse effects of radiation in individuals exposed to inhaled radioisotopes or incidental radiation.
亚麻籽（FS）是一种膳食补充剂，以其抗氧化和抗炎特性而闻名。肺组织的辐射暴露要么是在治疗胸腔恶性肿瘤时给予治疗，要么是在吸入放射性同位素释放后意外暴露，例如在放射性分散装置（RDD）爆炸后。这种暴露与肺部炎症、氧化组织损伤和不可逆的肺纤维化有关。我们之前报道过，饮食中的 FS 可预防胸部 X 射线放射治疗（XRT）的啮齿动物模型中的肺炎。然而，亚麻籽在暴露后减轻辐射影响的治疗用途从未得到过评估。
我们在两项独立的实验中（每组 n = 15-25 只小鼠）评估了 10%FS 或等热量对照饮食对接受单次 13.5 Gy 胸部 XRT 后 0、2、4、6 周的小鼠的影响，并将其与预防性给予的既定辐射防护饮食进行了比较，该饮食在 XRT 前 3 周开始给予。在 XRT 后四个月评估肺的血氧水平、炎症和纤维化。
喂食 0%FS 饮食的辐照小鼠的 4 个月存活率为 40%，而喂食 FS 的辐照小鼠组的存活率为 70-88%。此外，与喂食 0%FS 的小鼠相比，所有喂食 FS 的辐照小鼠的纤维化程度都有所降低。所有辐照的 FS 喂养小鼠的肺 OH-脯氨酸含量范围为 96.5 ± 7.1 至 110.2 ± 7.7 μg/ml（平均值 ± SEM），而喂食 0%FS 的小鼠为 138 ± 10.8 μg/ml。同时，所有 FS 喂养组的支气管肺泡灌洗液（BAL）蛋白和与辐射恶病质相关的体重减轻均显著减少。除了 FS 饮食在 XRT 后 4 周和 6 周延迟时，肺部炎症细胞浸润也显著减少。所有喂食 FS 的小鼠（辐照或未辐照）的血氧水平均高于喂食 0%FS 的小鼠。同样，BAL 液中的多重细胞因子分析显示，喂食 FS 的小鼠的特定炎症细胞因子显著减少。
XRT 后给予饮食 FS 通过减少肺纤维化、炎症、细胞因子分泌和肺损伤来减轻辐射影响，同时提高小鼠的存活率。FS 的饮食补充可能是一种有用的辅助治疗方法，可以减轻吸入放射性同位素或意外辐射暴露个体的辐射的不良影响。
