Mice in Research

The laboratory mouse (Mus musculus) is descended from the Western house mouse (Mus domesticus). They are widely used in research for several reasons: genetically they are very similar to humans, they are easy to maintain, fertile, and they have a short life span.It is also possible to genetically manipulate them.[1]

Inbred mice have been developed in the last century. The first inbred strain, the DBA mouse,was developed by the founder of Jackson Laboratories, Clarence Little, in 1909, followed by the C57Bl/6 in 1921.[2]Over 450 strains of inbreds are currently available to researchers. These models include a variety of immunodeficient strains, tumor forming strains, and obese mice.

The first transgenic mouse was produced in 1982, with the insertion of a growth hormone gene into an inbred mouse[3].Continuing advances in genetic manipulation have provided a great number of animal models for specific diseases.

While not covered by the Animal Welfare Act, mice used in federally funded projects are covered by Public Health Service Policy, administered by the Office of Laboratory Animal Welfare (OLAW) and the ILAR Guide for the Care and Use of Laboratory Animals.

In addition to Mus species, several other species are used in research, including Peromyscus and Onychomys.These animals are covered by the Animal Welfare Act.Mice are nocturnal, being most active at night.After breeding, a copulatory plug forms in the female. Gestation is roughly 18-20 days and mice are born naked and hairless (altricial). Mice are housed most often in shoebox cages with contact bedding.Since they are nest-builders, suitable nesting material should be provided. They are fed a standardized diet and provided water ad lib.

Mice are social animals, so group housing is preferred.Males used for breeding may be difficult to group house, but the addition of enrichment to cages reduces aggressive behavior. Any enrichment that encourages natural behaviors, such as nest-building and foraging, or activity contributes to animal well-being.

Mice are used in the study of genetics, cancer, immunology, infectious disease, ageing, and bioterrorism research.

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 [1] Human Genome Project http://www.ornl.gov/sci/techresources/Human_Genome/faq/compgen.shtml#whymice

[2] http://www.animalresearch.info/en/medical/timeline/miceandgenetics