December 7, 2004

Duke Study on Chemicals to Use Tiny Worms

DURHAM, N.C. (AP) -- Tiny worms are taking the place of laboratory rats and mice for a Duke University scientist studying the effect of chemicals on the body.

Researcher Jonathan Freedman has a $4 million contract from the National Toxicology Program to develop rapid toxicology tests on C. elegans roundworms.

The worms easily could flag which chemicals might harm babies before birth, threaten brain damage in adults or otherwise create trouble, Freedman said.

They may not seem like much, but the colorless microscopic worms share molecular similarities with humans. And they're cheap.

"We're not saying that because we see an effect in worms, the effect will be the same in humans," said Freedman, who has long used C. elegans to study ways toxic materials change how genes function. "We're saying if we see effects in worms, we should look in mice or humans."

New insight from worms, and maybe down the road from special breeds of fish or flies, may help the National Toxicology Program in Research Triangle Park better identify risky chemicals.

As it works to update testing techniques, the toxicology program has financed Freedman and other researchers in an effort to reduce the costs and suffering of traditional tests.

Each of the eight to 10 cancer tests that the program funds a year exposes 850 rodents to a suspicious chemical for as long as two years at a cost up to $3 million.

"We're looking at a lot of animal models. The science has changed. What we do, we can do differently," said NTP associate director Christopher Portier.

Made up of only 959 cells - compared with billions or trillions in most mammals - the worms are simple, see-through tubes whose insides are visible through a microscope. Normally they live on bacteria in soils around the world.

Freedman can raise hundreds of thousands in petri dishes he keeps in plastic shoe and sweater boxes in climate-controlled chambers in his lab.

The creatures have nervous, digestive, reproductive and muscular systems as well as genes that are easily altered during a 10-day life span.

With C. elegans, researchers can quickly tell when something is wrong. Scientists know the precise order in which the animals should change from a single cell to a worm. They can quantify when worms grow slowly, move wrong or eat less. They can even make the worms glow when they turn on an inner defense to an outside poison.

Currently, Freedman is working to build a system that makes C. elegans useful not only in highly specialized labs such as his own, but also in quick toxicology screens that hunt down dangers from suspicious chemicals. His lab uses several small robots that permit him and his staff to treat, sort, measure, photograph and otherwise observe large numbers of worms quickly.

Worms as lab animals is an idea that appeals to groups opposed to the use of millions of rodents and other mammals in scientific tests each year, including People for the Ethical Treatment of Animals.

"We're concerned about the pain and suffering of any animals. We also know that vertebrates, perhaps, are capable of suffering more than most," said Troy Seidle, PETA's director of science policy. "The body count reduced by switching to this type of system would be substantial."


Duke University

Information from: The News & Observer, http://www.newsobserver.com