The massive recalls of Mattel Inc. in August withdrew over 13 million toys from store shelves as a health safety precaution because many contained lead paint.
Optometry professor Donald Fox is leading a team of six Ph.D. students to study the effects of lead exposure in mice.
Lead exposure is especially dangerous to infants, Fox said, because they are 50 times more susceptible to lead exposure in the nervous system. Exposure creates developmental problems for children that affect physical and intellectual development.
"Children and fetuses absorb 95 percent of the lead they take into their body," Fox said. "After a child is about 5 years old they turn to absorbing only 5 percent of the ingested lead."
In the research, the first step the group takes is to add lead to a female mouse’s water supply over the course of two weeks. Male mice are introduced to impregnate the females. During fetus development and after birth, researchers extract the retina at specific gestation and post-partum times to study the differences.
"The mouse genome is very similar to the human genome and mice respond very similarly to drugs and chemicals to humans," said third-year Ph.D. biology and biochemistry student Ryan Hamilton.
Fox said that the group is taking a different approach to study lead exposure by looking into the accumulation of effects rather than immediately expose mice to lead. Fox said that the research is focusing on the development of the eyes of a fetus.
"Most laboratories look at the big amounts (of toxins) that we know causes death," Shawnta Chaney, a second-year biology and biochemistry Ph.D. student said. "What we are studying is more relevant to what we see, such as a child eating a paint chip."
Children affected by lead exposure through lead paint chips, contaminated water and dust inhalation often have learning problems and generally have an intelligent quotient that is approximately 4 to 5 percent lower than the average, according to a 1992 study published by the National English Journal of Medicine. Children up to 5 years old are most vulnerable to lead exposure.
"The effects are permanent," Fox said. "They are developmental-stage specific. If the child gets exposed to lead when they are 2 years old, all the cells in the brain, especially the retina and the auditory system are at least mostly well developed; it starts killing those cells."
While in the womb and during the first two years, a child’s brain is still developing and producing the necessary components for mental abilities, memory and learning, Fox said.
"During childhood development there’s one specific period of time during gestation – the first two trimesters the auditory and visual systems appear to be really sensitive to low levels of lead," Fox said.
The results so far have shown that mice have developed more eye cells and Fox said that the group is examining the outcomes.
"We’re not sure yet how lead is causing this to happen," Chaney said, referring to the pre-natal increase in retinal cells. "Just because the cells are there, more cells does not necessarily mean good effects because there’s a threshold of how much is good and how much is too much."
If any items in your home contain lead, they should be disposed as toxic products by taking them to a recycling center.
