U.Va. Research Finds Effects of Common Chemical BPA Span Generations
Bisphenol A, or BPA – a chemical that commonly leaches into food
and drink from cans and plastic containers – can alter the behavior
of mice for generations after exposure, research led by the
University of Virginia
School of Medicine shows.
The
researchers exposed female mice to the compound prior to and during
pregnancy, feeding them sufficient doses to create a BPA level in the
blood equivalent to what is typically found in humans. The researchers
then examined the genetic effects on subsequent generations. They
found that the initial BPA exposure continued to affect gene
expression and shape social behavior in the fourth generation – the
last examined – though there had been no additional exposure to the
chemical.
The researchers believe BPA has trans-generational
effects in people the same as it does in mice. "Based on our data,
and the results from others, it is clear the effects of this chemical
are going to be with us for a long, long time," said Emilie F.
Rissman, the study's lead investigator and a professor of
biochemistry and molecular genetics at the School of Medicine.
BPA
is an endocrine disruptor, meaning it interferes with the body's
hormone system. The man-made chemical is commonly used in polycarbonate
plastics, and it is often found in can linings and food and drink
packaging. Because BPA is water-soluble, it can leach into food and
drink, especially when the container gets hot or if the food is
acidic. This is the primary way people are exposed to BPA.
A
survey conducted by the Centers for Disease Control and Prevention in
2003-04 found detectable levels of BPA in 93 percent of 2,517 urine
samples taken from Americans age 6 and older.
In examining the
trans-generational effects of BPA, the researchers looked at the
social interactions between pairs of juvenile mice in the generations
after exposure to BPA. They evaluated the amount of time the mice
spent exploring their environment and the amount of time they spent
engaged in social activities. They also conducted targeted genetic
testing to determine BPA's effects on genetic expression patterns in
the brain.
researchers found that the mice exposed to BPA
while in the womb were less social than mice that had not been
exposed. By the third subsequent generation, the behavior had
flipped: Mice descended from the BPA-exposed mouse were more social
than the control group.
The researchers' conclusion: "Exposure to a
low dose of BPA, only during gestation, has immediate and
long-lasting, trans-generational effects," they write in a paper
published online in the journal Endocrinology.
While the
researchers believe BPA may have trans-generational effects in humans
as well, the effects may manifest differently.
"While we
certainly observed behavioral changes that were passed from
generation to generation with subsequent exposure, I cannot say for
sure these effects would be the same in humans," Rissman said.
"However, as fellow mammals with a 99 percent similarity in their
genomes, mice are a good laboratory model for investigations like
these, which simply cannot be done in people. While work in humans is
correlational, it is important and worth examination."
The researchers next plan to examine the mechanism by which BPA is affecting genes.
Source:
http://insciences.org/article.php?article_id=10841
