Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI.
Department of Medicine, University of Maryland School of Medicine and the Baltimore VA Medical Center, Baltimore, MD.
Health Phys. 2019 Apr;116(4):566-570. doi: 10.1097/HP.0000000000000944.
It has been speculated that the addition of antioxidants to diet could act as either radioprotectors or as mitigators of radiation injury. In preparation for studies of the mitigation efficacy of antioxidants, rats were placed on a modified version of AIN-76A, the diet typically used in such studies. This AIN-76A diet is refined and has no synthetic antioxidants or isoflavones. Compared to the natural-ingredient Teklad 8904 diet used in previous studies, use of the AIN-76A diet from 1-18 wk after irradiation significantly reduced injury in a radiation nephropathy model. A confirmation study included an additional arm in which the AIN-76A diet was started 2 wk prior to irradiation; again, the switch to AIN-76A postirradiation mitigated radiation nephropathy (p < 0.001), but switching to the AIN-76A diet preirradiation had no effect (p > 0.2). The two diets do not differ in salt content, but the AIN-76A diet is somewhat lower in protein (18% vs. 24%). The protein source (primarily soy in Teklad 8904 vs. casein in AIN-76A) might explain the effects. However, replacing the casein in AIN-76A with soy did not change the mitigation efficacy of the diet (p > 0.2 for comparison of the different AIN-76A diets). A similar study in a rat radiation pneumonitis model also suggested mitigation by postirradiation use of AIN-76A, although the effect was not statistically significant (p = 0.07). In conclusion, base diet alone can have biologically significant effects on organ radiosensitivity, but the mechanistic basis for the effect and its dependence of timing relative to irradiation are unclear.
有人推测，在饮食中添加抗氧化剂可以起到辐射防护剂或减轻辐射损伤的作用。为了准备研究抗氧化剂的缓解效果，将大鼠置于改良版 AIN-76A 上，该饮食通常用于此类研究。这种 AIN-76A 饮食经过精制，没有合成抗氧化剂或异黄酮。与之前研究中使用的天然成分 Teklad 8904 饮食相比，在辐射后 1-18 周使用 AIN-76A 饮食可显著减轻辐射肾病模型中的损伤。一项确认研究包括一个额外的分支，其中 AIN-76A 饮食在辐射前 2 周开始；同样，辐射后切换到 AIN-76A 饮食可减轻辐射肾病（p < 0.001），但辐射前切换到 AIN-76A 饮食则没有效果（p > 0.2）。两种饮食在盐含量上没有差异，但 AIN-76A 饮食的蛋白质含量略低（18%对 24%）。蛋白质来源（Teklad 8904 中的主要是大豆，AIN-76A 中的是乳清蛋白）可能解释了这些效果。然而，用大豆代替 AIN-76A 中的乳清蛋白并没有改变饮食的缓解效果（不同 AIN-76A 饮食之间的比较 p > 0.2）。在大鼠辐射性肺炎模型中的类似研究也表明，辐射后使用 AIN-76A 可减轻疾病，但效果没有统计学意义（p = 0.07）。总之，基础饮食本身可以对器官辐射敏感性产生具有生物学意义的影响，但影响的机制基础及其与辐射的时间关系尚不清楚。
