Spoiled Stores: Contamination of aged rodent supply impedes research (Experimental resources)
Authors: Davenport R. John 
Published: August 2003

Like bakers forced to grow wheat, scientists now find themselves with the burden of producing their own raw materials for studies of aging. A central supply of laboratory mice is genetically contaminated, curtailing the availability of animals for 2 years, National Institute on Aging (NIA) officials informed researchers on 8 May. The situation threatens to invalidate results from existing research projects and delay future studies.

NIA provides aged mice to researchers at academic and nonprofit institutions. Harlan Sprague Dawley Inc., an Indianapolis-based commercial supplier of laboratory animals, maintains the animals under contract with NIA. The cause of the contamination is unknown, but it appears to have affected mice in two environmentally isolated chambers. One contains half of NIA's aged C57BL/6 mice, the strain most commonly used for studies on aging. The two enclosures together house all of NIA's calorically restricted animals. (Caloric restriction extends rodent life-span.) Several hybrid lines are also affected. No one knows how many animals are contaminated because only a fraction of them has been tested.

Last month, a researcher notified NIA after her experimental results suggested that some animals obtained from the colony didn't carry genes that they were supposed to have, according to Nancy Nadon, chief of the Office of Biological Resources and Resource Development at NIA. Nadon says she reviewed genetic test results, which revealed that the contamination arose in spring 2000. According to NIA's contract with Harlan, the company bears responsibility for monitoring sample animals for genetic contamination and for immediately reporting any problems to NIA. Harlan executive vice president Jack McGinley confirmed the genetic contamination but would not elaborate on the testing procedure or why 2 years elapsed before the contamination came to light.

NIA will use its remaining stock to replace tainted animals that already have been shipped to investigators. Nadon anticipates that no new requests will be filled until June or July; those orders will go to NIA grantees only, and delays are likely. According to NIA, dieting mice won't be available for at least 2 years--the amount of time required to develop a new colony. Researchers can arrange through NIA for the Jackson Laboratory in Bar Harbor, Maine, to test animals or tissue for genetic contamination. "A lot of completed work can be validated if we can show that some of the animals are OK," says Nadon.

NIA supplies about 20,000 mice a year, and 300 different investigators received animals during the 2-year period since the contamination occurred. The consequences are already clear to some scientists. "A research project for which we just received funding has been halted," says biochemist Stephen Spindler of the University of California, Riverside. "We're going to have to buy young animals and age them ourselves before we can begin the study." That means spending nearly 3 years on a study that might otherwise have taken 3 months.

--R. John Davenport

Further Reading

National Institute on Aging Aged Rodent Colonies

http://www.nia.nih.gov/research/rodent.htm

Harlan Sprague Dawley Inc.
http://www.harlan.com

The Jackson Laboratory
http://www.jax.org