Internal exposure to neutron-activated (56)Mn dioxide powder in Wistar rats-Part 2: pathological effects.
Internal exposure to neutron-activated (56)Mn dioxide powder in Wistar rats-Part 2: pathological effects.
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DOI：
10.1007/s00411-016-0676-z
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发表时间：
2017-03
影响因子：
1.7
通讯作者：
Hoshi M
中科院分区：
文献类型：
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作者：
Shichijo K;Fujimoto N;Uzbekov D;Kairkhanova Y;Saimova A;Chaizhunusova N;Sayakenov N;Shabdarbaeva D;Aukenov N;Azimkhanov A;Kolbayenkov A;Mussazhanova Z;Niino D;Nakashima M;Zhumadilov K;Stepanenko V;Tomonaga M;Rakhypbekov T;Hoshi M
为了充分了解广岛和长崎原子弹爆炸对幸存者造成的辐射影响，除了直接从原子弹接受的初始辐射外，还应考虑土壤和其他材料中中子诱导放射性同位素的辐射。这对于评估爆炸后不久搬到这些城市并可能吸入活性放射性“尘埃”的人的辐射风险可能很重要。已知锰-56是中子在土壤中产生的主要放射性同位素之一。由于其物理半衰期短，56 Mn在爆炸后的最初几个小时内会释放残余辐射。因此，在本研究中，Wistar大鼠内暴露于56 Mn的生物学效应进行了研究。MnO 2粉末被中子束活化以产生放射性56 Mn。将大鼠分为4组：56 Mn组、非放射性Mn组、60 Co γ射线（2戈伊，全身照射）组和对照组。在暴露后第3、14和60天，处死动物，解剖主要器官并进行组织病理学分析。正如所附出版物更详细地描述的那样，在大鼠的消化系统中观察到最高的内部辐射剂量，其次是肺部。结果发现，有丝分裂细胞的数量增加，在小肠的第3天后56锰和60钴暴露，这种变化只持续在56锰暴露的动物。尽管辐射剂量相当低（小于0.1戈伊），但仅暴露于56 Mn时肺组织受到严重损伤。这些数据表明，体内暴露于56 Mn对肺和小肠具有显著的生物学影响。
To fully understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil and other materials should be considered in addition to the initial radiation directly received from the bombs. This might be important for evaluating the radiation risks to the people who moved to these cities soon after the detonations and probably inhaled activated radioactive “dust.” Manganese-56 is known to be one of the dominant radioisotopes produced in soil by neutrons. Due to its short physical half-life, 56Mn emits residual radiation during the first hours after explosion. Hence, the biological effects of internal exposure of Wistar rats to 56Mn were investigated in the present study. MnO2 powder was activated by a neutron beam to produce radioactive 56Mn. Rats were divided into four groups: those exposed to 56Mn, to non-radioactive Mn, to 60Co γ rays (2 Gy, whole body), and those not exposed to any additional radiation (control). On days 3, 14, and 60 after exposure, the animals were killed and major organs were dissected and subjected to histopathological analysis. As described in more detail by an accompanying publication, the highest internal radiation dose was observed in the digestive system of the rats, followed by the lungs. It was found that the number of mitotic cells increased in the small intestine on day 3 after 56Mn and 60Co exposure, and this change persisted only in 56Mn-exposed animals. Lung tissue was severely damaged only by exposure to 56Mn, despite a rather low radiation dose (less than 0.1 Gy). These data suggest that internal exposure to 56Mn has a significant biological impact on the lungs and small intestine.