Abstract
To investigate the biological effects of internal exposure of radioactive 56MnO2 powder, the major radioisotope dust in the soil after atomic bomb explosions, on male reproductive function, the gene expression of the testes and the prostate was examined. Ten-week-old male Wistar rats were exposed to three doses of radioactive 56MnO2 powder (41–100 mGy in whole body doses), stable MnO2 powder, or external 60Co γ-rays (2 Gy). Animals were necropsied on Days 3 and 61 postexposure. The mRNA expressions of testicular marker protein genes and prostatic secretory protein genes were quantified by Q-RT-PCR. On Day 3 postexposure, the testicular gene expressions of steroidogenesis-related enzymes, Cyp17a1 and Hsd3b1, decreased in 56MnO2-exposed groups. Germ cell-specific Spag4 and Zpbp mRNA levels were also reduced. On postexposure Day 61, the Cyp11a1 gene expression became significantly reduced in the testes in the group exposed to the highest dose of 56MnO2, while another steroidogenesis-related StAR gene mRNA level reduced in the 60Co γ-rays group. There were no differences in Spag4 and Zpbp mRNA levels among groups on Day 61. No histopathological changes were observed in the testes in any group following exposure. Expression in the prostatic protein genes, including CRP1, KS3, and PSP94, significantly decreased in 56MnO2-exposed groups as well as in the 60Co γ-rays group on Day 61 postexposure. These data suggest that the internal exposure to 56MnO2 powder, at doses of less than 100 mGy, affected the gene expressions in the testis and the prostate, while 2 Gy of external γ-irradiation was less effective.
Highlights
Notwithstanding the effects of the initial radiation from the atomic bombings in Hiroshima and Nagasaki, there have been concerns regarding the potentially significant influence of the residual radioactive dust on the health of those exposed
To understand the biological effects of the residual radioactive particles following an atomic bombing, we examined male Wistar rats exposed to 56MnO2 powder and found that internal exposure to this radioactive powder had higher biological impacts than external irradiation [3,4]
Testicular radiation doses were less than 110 mGy, the mRNA levels in several steroidogenesis related genes were affected on Days 3 and 61 postexposure as prostatic protein gene expressions were downregulated on Day 61 postexposure
Summary
Notwithstanding the effects of the initial radiation from the atomic bombings in Hiroshima and Nagasaki, there have been concerns regarding the potentially significant influence of the residual radioactive dust on the health of those exposed. The people who moved to these cities a short time after detonation were only exposed to residual radiation, likely via inhaling radioactive dust, and were reported to suffer from acute radiation syndromes [1]. A primary source of residual radiation was 56Mn, a radioisotope produced in the soil by the neutron beam from an atomic bomb explosion [2]. We investigated the biological effects of neutron-activated 56MnO2 powder in Wistar rats to gain a better understanding of the significance of residual radiation [3,4,5]. Histopathological changes were noted in the small intestine and lungs [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
