Scott Bobby R
Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM, 87108, USA,
J Cell Commun Signal. 2014 Dec;8(4):341-52. doi: 10.1007/s12079-014-0250-x. Epub 2014 Oct 17.
Humans are continuously exposed to ionizing radiation throughout life from natural sources that include cosmic, solar, and terrestrial. Much harsher natural radiation and chemical environments existed during our planet's early years. Mammals survived the harsher environments via evolutionarily-conserved gifts ̶ a continuously evolving system of stress-induced natural protective measures (i.e., activated natural protection [ANP]). The current protective system is differentially activated by stochastic (i.e., variable) low-radiation-dose thresholds and when optimally activated in mammals includes antioxidants, DNA damage repair, p53-related apoptosis of severely-damaged cells, reactive-oxygen-species (ROS)/reactive-nitrogen-species (RNS)- and cytokine-regulated auxiliary apoptosis that selectively removes aberrant cells (e.g., precancerous cells), suppression of disease promoting inflammation, and immunity against cancer cells. The intercellular-signaling-based protective system is regulated at least in part via epigenetic reprogramming of adaptive-response genes. When the system is optimally activated, it protects against cancer and some other diseases, thereby leading to hormetic phenotypes (e.g., reduced disease incidence to below the baseline level; reduced pain from inflammation-related problems). Here, some expressed radiation hormesis phenotypes and related mechanisms are discussed along with their implications for disease prevention and therapy.
人类在一生中持续受到来自自然源的电离辐射，这些自然源包括宇宙、太阳和地球辐射。在地球早期，存在更为恶劣的自然辐射和化学环境。哺乳动物通过进化保守的天赋——一个不断进化的应激诱导自然保护措施系统（即激活的自然保护[ANP]）——在更恶劣的环境中生存下来。当前的保护系统由随机（即可变）低辐射剂量阈值差异激活，在哺乳动物中最佳激活时包括抗氧化剂、DNA损伤修复、严重受损细胞的p53相关凋亡、活性氧（ROS）/活性氮（RNS）和细胞因子调节的辅助凋亡，后者选择性地清除异常细胞（如癌前细胞）、抑制促进疾病的炎症以及对癌细胞的免疫。基于细胞间信号的保护系统至少部分通过适应性反应基因的表观遗传重编程来调节。当该系统被最佳激活时，它能预防癌症和其他一些疾病，从而产生兴奋效应表型（如疾病发病率降低至基线水平以下；与炎症相关问题引起的疼痛减轻）。在此，将讨论一些已表达的辐射兴奋效应表型及其相关机制，以及它们对疾病预防和治疗的影响。
