ITHACA, N.Y. -- Lead in the drinking water of pregnant rats causes long-term damage to the immune systems of their offspring, according to studies at the Cornell University Institute for Comparative and Environmental Toxicology.
If the finding also holds true for pregnant women exposed to lead, it could help explain why some babies are born with a lifelong predisposition to asthma and other allergies, as well as cancers, say Cornell scientists who report the discovery in the current issue of the journal Toxicological Sciences (Vol. 42, pp. 129-135).
"We found that low levels of lead in embryos -- levels that do not affect the mother's immune system -- produce serious long-term immune system defects as the young rats mature," says Rodney R. Dietert, professor of immunotoxicology in Cornell's College of Veterinary Medicine. "These are immune changes that could increase their risk for allergic disease while reducing their immunity to tumors."
The Cornell researchers are now conducting parallel studies on early lead exposure with embryonic chickens as animal models, but have no plans to extend the studies at the university to humans. But humans subjects, they say, would not be hard to find.
"Unfortunately, pregnant women even in this country are exposed to these levels of lead through drinking water, old paint and other sources," Dietert said. "And the situation is worse in developing countries, where leaded gasoline is still sold and women work in factories where lead is used."
Lead exposure is just one of the risk factors for immune-related disease now under consideration by epidemiologists in the United States. Among other possible risk factors is early exposure to airborne particles, such as those found in air polluted with diesel engine fumes.
Studies at the Cornell toxicology institute and the university's veterinary college used Fischer 334 rats, a standard animal model for human cancer studies. The pregnant rats were given d
Contact: Roger Segelken
Cornell University News Service