Skip to comments.A little radiation is good for mice - Low doses of radioactivity led to healthier pups
Posted on 12/30/2012 10:15:02 AM PST by neverdem
X-rays may not heal broken bones, but low doses of ionizing radiation may spark other health benefits, a new study of mice suggests.
Radiation in high doses has well-known harmful effects. Scientists had thought low doses would do less extensive damage but could add up to big problems later. But radiation acts differently at low doses, producing health benefits for mice with an unusual genetic makeup, Randy Jirtle of the University of WisconsinMadison and colleagues report online November 1 in the FASEB Journal. Antioxidant vitamins, such as vitamins C and E, erased those health gains.
What goes on at high doses is not very predictive of what happens at low doses, says Edward Calabrese, a toxicologist at the University of Massachusetts-Amherst. Chemicals that are poisons at high doses may be growth or health promoters at low concentrations. Its a major observation that is still to be appreciated, he says.
Jirtles group studies mice known as viable yellow agouti mice. Scientists use them to gauge how diet, chemicals and other environmental conditions affect gene activity in animals, probably including humans. Agouti mice have a genetic quirk that causes the agouti gene to be turned on in all their body tissues. This results in yellow coats, obesity, diabetes and more cancer than normal. But attaching chemical tags to the DNA, a process called DNA methylation, around the agouti gene shuts the genes activity down, leading to lean, brown, healthy mice. Chemicals, stress or other factors that interfere with methylation shift the coat color and health status of the mice.
The scientists irradiated pregnant mice so that developing fetuses received doses between 0.4 centigrays and 7.6 centigrays. (A human dental X-ray delivers about 0.4 to 0.8 centigrays.) Some mice were put in the scanner but not irradiated. Mother mice that got radiation doses...
(Excerpt) Read more at sciencenews.org ...
Hormesis is a term used by toxicologists to refer to a biphasic dose response to an environmental agent characterized by a low dose stimulation or beneficial effect and a high dose inhibitory or toxic effect. In the fields of biology and medicine hormesis is defined as an adaptive response of cells and organisms to a moderate (usually intermittent) stress. Examples include ischemic preconditioning, exercise, dietary energy restriction and exposures to low doses of certain phytochemicals. Recent findings have elucidated the cellular signaling pathways and molecular mechanisms that mediate hormetic responses which typically involve enzymes such as kinases and deacetylases, and transcription factors such as Nrf-2 and NF-κB. As a result, cells increase their production of cytoprotective and restorative proteins including growth factors, phase 2 and antioxidant enzymes, and protein chaperones. A better understanding of hormesis mechanisms at the cellular and molecular levels is leading to and to novel approaches for the prevention and treatment of many different diseases.
Does whatever a Spider-Mouse does
Can he swing, on a web?
No he can’t, he’s a mouse.
I must have had 1000+ dental x-rays so far, with no discernible bad effects so far. Plus I eat a lot of radiated fruits. I am counting on collecting Social Security for 20 more years hahaha.
Makes sense, explains why the people at Chernobyl had much, much, less problems than predicted.
Don’t we get a good dose of radiation daily from natural sources, i.e., the sun?
“producing health benefits for mice with an unusual genetic makeup” ...so normal mice (without this unusual genetic makeup) would NOT experience this ‘benefit’? Wouldn’t they have said so if normal mice were unharmed?
So much hedging in this article; note the “probably in humans”. State of the art, massive, long-term, well-designed scientific studies like BEIR VI have shown, year after year, that there is no safe or beneficial radiation threshold and that even low dose radiation damages humans.
In the BEIR VI, researchers note low doses are especially damaging to young and to females (twice as damaging to girls than boys). The article doesn’t say but I am guessing they used adult mice for their “genetic anomaly” sample in order to avoid this sensitivity because damage to thyroid/endocrine/bone-marrow etc. would interfere with their study of this genetic anomaly.
Since BEIR VI and other studies have proven that low dose radiation is damaging to humans (and quantified the damage by age/gender), I don’t believe this research will be useful to humans unless used to treat a gentically anomalous human who is older and male and whose genetic anomaly is regarded as worse than the damage caused by radiation dosing.
“Makes sense, explains why the people at Chernobyl had much, much, less problems than predicted.”
Laughably false statement.
“Dont we get a good dose of radiation daily from natural sources, i.e., the sun?”
Yes, that’s why we wear sunblock to reduce incidence of skin cancer.
Ah...checking the article I see:
“Mother mice that got radiation doses between 0.7 and 3 centigrays had more pups with browner coats than did sham-irradiated mice. Browner coat colors among mice exposed to low-dose radiation were associated with higher levels of DNA methylation on the agouti gene, indicating that radiation does something to alter the chemical tagging.”
So irradiating the young altered their DNA. Not something we want to try unless you are a “viable yellow agouti mice”.
Correction - the latest version of the National Academy of Science Biological Effects of Ionizing Radiation is the BEIR VII.
“BEIR VII focuses on
the health effects of low levels of low linear energy transfer (low-LET) ionizing radiation such as x-rays
and gamma rays. The most recent BEIR report to address low level low-LET radiation was the BEIR V
report published in 1990. Humans are exposed to ionizing radiation from both natural and man-made
sources (see Figure 1). Very high doses can produce damaging effects in tissues that can be evident within
days after exposure. Late effects such as cancer, which can occur after more modest doses including the
lowdose exposures that are the subject of this report, may take many years to develop.”
This eminent scientist agrees:
Better living through chemistry!
Most people get too little radiation. Art Robinson worked on this and radiatoin hormesis appears to be beneficial. IIRC the lowest incident of skin cancer is among Australian life guards.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.