Researchers work to reduce animals killed in drug testing

Jan. 31 (UPI) -- A team of researchers from Hiroshima University in Japan have developed a non-invasive way to test inflammation in drug testing that would not involve killing lab animals.

Researchers from HU's Graduate School of Biosphere Science have created a technique to examine fatty tissues in lab animals that could reduce the numbers of lab mice killed and could change medicinal drug testing.

Previous methods that study inflammation in fatty tissue involved a large number of lab mice euthanized on a regular basis.

HU Associate Professor Noriyuki Yanaka and his team discovered a gene that is highly expressed in obese fatty tissue where macrophages cause inflammation.

The gene, Serum Amyloid A3, or Saa3, activates and can be detected when fatty tissue becomes inflamed.

Researchers attached the light-emitting luciferase gene from fireflies to Saa3's promoter region to create a gene that emits light when in inflamed fatty tissue. The gene was injected into fertilized mouse eggs to create transgenic mice. The mice were fed natural-wild diets and high-fat diets.

The researchers then used bioluminescence imaging to detect areas of light-emittance where inflamed fatty tissue was found. The mice fed a natural-wild diet showed no light emittance.

"Animal experimentation is a serious social problem in developed countries, with many animals being sacrificed in order to develop medicines, cosmetics and functional foods for humans," Yanaka said in a press release. "What we are proposing is a way to reduce not only the number of animals which are used in experiments, but also animal experiments themselves."

The study was published in the journal Nature.