[ RadSafe ] New study shows protective effect of CT scan X-ray on unborn mice

Scott, Bobby BScott at lrri.org
Mon Nov 12 18:34:50 CST 2012

Hi All,


A new study by A. J. Bernal et al. in the FASEB Journal (article
fj.12-220350) titled "Adaptive radiation-induced epigenetic alterations
mitigated by antioxidants" shows that low doses of X-rays from a Siemens
MicroCT scanner caused protective rather than harmful epigenetic changes
in male mice exposed during gestation. The researchers used viable
yellow agouti mice which are especially sensitive to environmental
stresses that change the fetal epigenome. An epigenome consists of a
record of the chemical changes to the DNA and histone proteins
(associated with DNA) of an organism. Epigenetic changes can arise via
changes in the structure of chromatin and by other means and this can
lead to changes in genes that are expressed (activated) and not
expressed (silenced). The epigenetic activation of genes we have called
"epiactivation" and the epigenetic silencing we have called
"episilencing" (Scott et al. 2009; Scott 2011, 2012).  When such changes
occur throughout the cell community studied, we have called this an
epigenetically-regulated, cell-community-wide (epicellcom) response
(Scott 2011).


The epigenome influences how an organism develops within the pregnant
mother. Unlike the underlying genome (DNA sequence) which is largely
fixed for a given individual, the epigenome can be changed by
environmental stresses. The protective epigenetic changes studied by
Bernal et al. demonstrated hormetic responses (radiation hormesis) that
occurred throughout the organism (i.e., and epicellcom response) and
were reflected in the coat color of the mice. The protective changes
were associated with lower risks of developing obesity and cancer.
Related to the linear-no-threshold hypothesis, the authors state in the
abstract that their research findings "bring into question the
assumption that every dose of radiation is harmful".




Scott BR et al. 2009. Radiation-stimulated epigenetic reprogramming of
adaptive-response genes in the lung: An evolutionary gift for mounting
adaptive protection against lung cancer.  Dose-Response 7(2):131.


Scott BR. 2011. Modeling DNA double-strand break repair kinetics as an
epiregulated cell-community-wide (epicellcom) response to radiation
stress. Dose-Response 9:579-601.


Scott BR. 2012. First generation stochastic gene episilencing (STEP1)
model and applications to in vitro carcinogen exposure. Dose-Response


Best wishes,


B. R. Scott

Lovelace Respiratory Research Institute

Albuquerque, NM, USA



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