Internal exposure to neutron-activated56Mn dioxide powder in Wistar rats-Part 2: pathological effects.
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 to56Mn were investigated in the present study. MnO2powder was activated by a neutron beam to produce radioactive56Mn. Rats were divided into four groups: those exposed to56Mn, to non-radioactive Mn, to60Co 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 after56Mn and60Co exposure, and this change persisted only in56Mn-exposed animals. Lung tissue was severely damaged only by exposure to56Mn, despite a rather low radiation dose (less than 0.1 Gy). These data suggest that internal exposure to56Mn has a significant biological impact on the lungs and small intestine.
Nagasaki University, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan.
Kazuko
K
Shichijo
Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima,, 734-8553, Japan. nfjm@hiroshima-u.ac.jp.
Nariaki
N
Fujimoto
Semey State Medical University, Republic of Kazakhstan, Abay Str., 103, Semey, 071400, Kazakhstan.
Darkhan
D
Uzbekov
Semey State Medical University, Republic of Kazakhstan, Abay Str., 103, Semey, 071400, Kazakhstan.
Ynkar
Y
Kairkhanova
Semey State Medical University, Republic of Kazakhstan, Abay Str., 103, Semey, 071400, Kazakhstan.
Aisulu
A
Saimova
Semey State Medical University, Republic of Kazakhstan, Abay Str., 103, Semey, 071400, Kazakhstan.
Nailya
N
Chaizhunusova
Semey State Medical University, Republic of Kazakhstan, Abay Str., 103, Semey, 071400, Kazakhstan.
Nurlan
N
Sayakenov
Semey State Medical University, Republic of Kazakhstan, Abay Str., 103, Semey, 071400, Kazakhstan.
Dariya
D
Shabdarbaeva
Semey State Medical University, Republic of Kazakhstan, Abay Str., 103, Semey, 071400, Kazakhstan.
Nurlan
N
Aukenov
National Nuclear Center of the Republic of Kazakhstan, Krasnoarmeyskaya Str., 2, Build 54 B, Kurchatov, 071100, Kazakhstan.
Almas
A
Azimkhanov
National Nuclear Center of the Republic of Kazakhstan, Krasnoarmeyskaya Str., 2, Build 54 B, Kurchatov, 071100, Kazakhstan.
Alexander
A
Kolbayenkov
Nagasaki University, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan.
Zhanna
Z
Mussazhanova
Nagasaki University, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan.
Daisuke
D
Niino
Nagasaki University, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan.
Masahiro
M
Nakashima
L.N. Gumilyov Eurasian National University, Munaitpasova Str.,13, Astana, 010008, Kazakhstan.
Kassym
K
Zhumadilov
A. Tsyb Medical Radiological Research Center, National Medical Research Radiological Center, Ministry of Health of Russian Federation, Koroleva Str. 4, Obninsk, Kaluga region, 249036, Russia.
Valeriy
V
Stepanenko
Nagasaki University, 1-12-4, Sakamoto, Nagasaki, 852-8523, Japan.
Masao
M
Tomonaga
Semey State Medical University, Republic of Kazakhstan, Abay Str., 103, Semey, 071400, Kazakhstan.
Tolebay
T
Rakhypbekov
Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima,, 734-8553, Japan.
Masaharu
M
Hoshi
D000818:Animals; D008297:Male; D017895:Manganese Compounds / Q000009:adverse effects*; D009502:Neutrons; D054043:Nuclear Weapons; D010087:Oxides / Q000009:adverse effects*; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology* / Q000473:pathology*; D011851:Radioactivity; D051381:Rats; D017208:Rats, Wistar
D017895:Manganese Compounds; D010087:Oxides; C016552:manganese dioxide
A-bombing; Internal radiation exposure; Lung; Manganese-56; Rats