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Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.49 [2011] >
IJEB Vol.49(12) [December 2011] >
| Title: | Transient cell function disruption by low dose acute exposure of ionizing radiation |
| Authors: | Saxena, Priyanka
Bhatnagar, Aseem
Nishad, Dhruv Kumar
Tyagi, Ritu
Rana, Poonam
Ali, Shakir
Mittal, Gaurav |
| Keywords: | Thallium-201
Iodine-131
Thyroid stunning
Na+-K+ ATPase pump |
| Issue Date: | Dec-2011 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | Incubation of BMG-1 cells with thallium chloride
(201Tl) in the range of diagnostic dose did not show a smooth uptake
curve and appeared to have an unsuspected deviation in initial phase. In the present
study this unexpected phenomenon was explored, using commonly used
radionuclides (viz., 201Tl and 131I). Comparison was made
with technetium-99m pertechnetate (99mTcO4-)
and technetium-99m labeled methoxyisobutylisonitrile (99mTc-MIBI)
that are known to show conventional 2 phase graph representing inflow and
outflow segments. Serial in vitro, ex-vivo and in vivo gamma scintigraphy as well as NMR spectroscopy experiments were
conducted to corroborate the results. BMG-1 cells demonstrated a four-phase
uptake pattern with 201Tl as compared to a conventional biphasic
pattern with 99mTc-MIBI. Flow cytometry data however did not reveal any
201Tl induced cell injury. Further, mice tissue extracts injected
with 201Tl also showed a transient depression in its uptake.
Scintigraphy experiments in rabbits administered with diagnostic dose of 201Tl
and 131I confirmed the in
vitro and ex vivo findings. Further,
proton NMR spectroscopy showed decrease in the level of
choline at 3 h and 24 h in 201Tl treated animals as compared to
control. Phosphoethanolamine peak firstly decreased at 3 h but reached normal
level at 24 h time point. No significant change was observed in the level of
betaine. This transient reduction in internalization of
201Tl and 131I may represent a hitherto unknown acute
effect of low dose radiation, i.e., transient depression in Na+-K+
ATPase pump activity without any apparent evidence of cell damage, representing
a transient cell membrane dysfunction. The phenomenon may present a
mechanistical explanation of ‘thyroid stunning’ at cellular level and suggest that
it may be more universal in nature than suspected till now. |
| Page(s): | 895-903 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-1009 (Online); 0019-5189 (Print) |
| Source: | IJEB Vol.49(12) [December 2011]
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