Elucidation of mechanisms for responses of normal tissues exposedto low dose radiation in the radiation cancer therapy

为探讨正常组织对低剂量辐射的反应机制，用0.01~2.0Gy射线对ICR小鼠(JCL：ICR，5周龄，雄性)进行全身照射，观察其对小肠和睾丸细胞凋亡的诱导作用。2.0Gy射线照射后，小鼠肠隐窝和睾丸小叶最外层可特异性地诱导细胞发生凋亡。此外，0.01~0.05Gy射线照射组小鼠的肠道和睾丸组织中均可检测到细胞凋亡。肠上皮细胞凋亡率呈剂量依赖性增加。免疫组织化学分析表明，肠或睾丸中诱导的凋亡细胞分别为组织干细胞或生殖细胞及其前体细胞。

To elucidate mechanisms for responses of normal tissues exposed to low dose radiation, the induction of apoptosis in the small intestine and testis from whole body-irradiated ICR mice (Jcl:ICR, 5 weeks old, male) with carbon ion beams at 0.01 ~ 2.0 Gy. The apoptosis was specifically induced in the intestinal crypts and the outermost region of lobuli testisin the mice irradiated at 2.0 Gy. In addition, the apoptosis was detected in the intestine and testis from the mice irradiated at 0.01 ~ 0.05 Gy in the same manner. The incidence of apoptotic cells in the intestine increased in the dose-dependent manner. Finally, the immunehistochemical analysis indicated that the apoptotic cells induced in the intestine or testis were the tissue or germ stem cells and their progenitor cells, respectively.