Biological impacts on the lungs in rats internally exposed to radioactive 56MnO2 particle

Nariaki Fujimoto,Bakhyt Ruslanova,Zhaslan Abishev,Andrey Kaprin,Sergey Ivanov,Gaukhar Amantayeva,Rakhimzhanova Farida,Kasuke Nagano,Masaharu Hoshi,Marat Sandybayev,Kassym Zhumadilov,Nailya Chaizhunussova,Dariya Shabdarbayeva,Valeriy Stepanenko

doi:10.1038/s41598-021-90443-9

Abstract

To understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil should be considered in addition to the initial radiation directly received from the bombs. 56Mn, which emits both β particles and γ-rays, is one of the dominant radioisotopes created in soil by neutrons from the bomb. Thus we investigated the biological effects of internal exposure to 56MnO2 particle in the lung of male Wistar rats comparing to the effects of external 60Co-γ irradiation. Absorbed doses of internal irradiation of lungs were between 25 and 65 mGy in 56MnO2-exposed animals, while the whole body doses were between 41 and 100 mGy. Animals were examined on days 3 and 61 after the exposure. There were no remarkable pathological changes related to 56MnO2 particle exposure. However, mRNA and protein expressions of aquaporin 5 increased significantly in the lung tissue on day 3 postexposure in 56MnO2 groups (by 1.6 and 2.9 times, respectively, in the highest dose group). Smad7 mRNA expression was also significantly elevated by 30% in the highest dose group of 56MnO2. Our data demonstrated that internal exposure to 56MnO2 induced significant biological responses including gene expression changes in the lungs, while external 60Co-γ irradiation of 2 Gy did not show any changes.

Highlights

To understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil should be considered in addition to the initial radiation directly received from the bombs. 56Mn, which emits both β particles and γ-rays, is one of the dominant radioisotopes created in soil by neutrons from the bomb
AQP1 is located in microvascular endothelia, while AQP 4 is in airway epithelia and AQP 5 is in type I alveolar epithelial cells, all of which are involved in the transport of liquid to maintain a normal physiological status of the lung[13]
We examined male Wistar rats exposed to 56MnO2 powder to understand the biological effects of the possible residual radioactive particles from atomic bombing[3]

Summary

Introduction

To understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil should be considered in addition to the initial radiation directly received from the bombs. 56Mn, which emits both β particles and γ-rays, is one of the dominant radioisotopes created in soil by neutrons from the bomb. We investigated the biological effects of internal exposure to 56MnO2 particle in the lung of male Wistar rats comparing to the effects of external 60Co-γ irradiation. Our data demonstrated that internal exposure to 56MnO2 induced significant biological responses including gene expression changes in the lungs, while external 60Co-γ irradiation of 2 Gy did not show any changes. We initiated to investigate the biological effects of this residual radioisotope by exposing laboratory rats to 56MnO2 particles and reported possible pathological changes in the lung[3]. We exposed the necessary numbers of male Wistar rats to three different doses of radioactive 56MnO2 powder, or stable MnO2 powder to further examine our previous findings. The animals were examined on days 3 and 61 postexposure because our previous study indicated that pathological changes occurred in the lung on day 3 and were recovered by day 6 03

Methods

Results

Conclusion