A new study, funded in part by NIEHS, found that dioxin affects not
only the health of an exposed rat, but also unexposed descendants
through a mechanism of epigenetic transgenerational inheritance.
was conducted in the laboratory of Michael Skinner, Ph.D.,
a professor in the Center for Reproductive Biology in the
Department of Biological Sciences at Washington State University (WSU)
who designed the study.
Co-authors included assistant research professor Mohan
Manikkam, Ph.D., research technician Rebecca Tracey, and postdoctoral
researcher Carlos Guerrero-Bosagna, Ph.D.
“Although not designed
for risk assessment, these results have implications for the human
populations that are exposed to dioxin and are experiencing declines in
fertility and increases in adult onset disease, with a potential to
transmit them to later generations,” the authors concluded.
Dangers of dioxin last for decades after initial exposure
2,3,7,8-tetrachlorodibenzo[p]dioxin (TCDD), is a chemical compound that
constitutes part of the Agent Orange herbicide used as a defoliant in
the Vietnam War. According to research cited in the study, exposure is
estimated to have caused 400,000 deaths and 500,000 birth defects.
Dioxin has also been released from industrial accidents, leading to
human exposures. Due to its extremely long half-life of up to 10 years
in humans, dioxin may still affect pregnancies occurring even 20 years
In the Skinner group’s experiments, exposure to
dioxin caused changes in the DNA methylation patterns of sperm that were
transmitted across generations, in an imprinted-like manner, to affect
the health of multiple generations of descendents. The grandchildren of
exposed rats showed dioxin-induced effects ranging from polycystic
ovarian disease to kidney disease. The work raises the serious concern
that even if toxic chemicals, such as dioxin, were completely removed
from the environment, they could continue to cause disease for multiple
READ MORE: http://www.niehs.nih.gov/news/newsletter/2012/11/science-dioxin/index.htm