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Short-term exposure to high levels of natural external gamma radiation does not induce survival adaptive response
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S.M.J. Mortazavi   , A. Niroomand-Rad , H. Mozdarani , P. Roshan-Shomal , S.M.T. Razavi-Toosi , H. Zarghani |
| , mozdarh@modares.ac.ir |
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Abstract: (11063 Views) |
| Background: In some areas of Ramsar, a city in
northern Iran, residents receive a much higher annual
radiation exposure than is permitted for radiation
workers. Induction of adaptive response in residents
of Ramsar has been reported previously. In this study
induction of such a response in short term exposure
to high background levels of gamma radiation is
investigated. Materials and Methods: Fifty male NMRI
mice were randomly divided into four groups of 10-17
animals and 53 Wistar rats were randomly divided
into five groups of 10-12 animals were studied.
Animals in the 1st group were kept for 7 days in an
outdoor area with normal background radiation while
the 2nd, 3rd, 4th and 5th (in case of rats) groups were
kept in 3 different outdoor areas with naturally
elevated levels of gamma radiation. Animals were
then exposed to a lethal dose of 8 Gy gamma
radiation. Results: For mice, 30 days after exposure
to lethal dose, the survival fraction for the control
group was 40% while the 2nd, 3rd, and 4th groups had
survival rates of 20%, 33.30%, and 35.20%,
respectively. For rats, 30 days after exposure to the
lethal dose, the survival fraction for the control group
was 40% while the 2nd, 3rd, 4th and 5th groups had
survival rates of 20%, 41.6%, 60.0% and 35.7%,
respectively. Conclusion: Results indicate that shortterm
exposure to extremely high levels of natural
gamma radiation (up to 196 times higher than the
normal background) do not lead to induction of
survival adaptive response. Iran. J. Radiat. Res., 2012
10(3‐4): 165‐170
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| Keywords: Ramsar, natural background radiation, survival adaptive response, short term exposure. |
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Full-Text [PDF 290 kb]
(3849 Downloads)
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Type of Study: Original Research |
Subject:
Radiation Biology
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