Along with rats and other rodents, mice make up the majority of animals used for medical research. Their small size, low cost and ease in handling make them ideal for laboratory experiments. In addition, scientists can breed different strains of mice with natural genetic deficiencies to achieve models of human diseases. The following are fields of medicine and research in which the use of mice has advanced understanding and show potential for cures.
Through breeding, scientists have developed mice with leukemia, breast cancer and many other types of cancer, allowing new treatments to be tested on animal models instead of humans.
- Scientists have discovered that cells from certain human tumors could be placed into immunologically deficient (“nude”) mice and would not be rejected. This allows the study of human cancer cells without risking human lives.
- Studies with mice have shown that the immune system can be stimulated by genetically altered tumor cells, leading to hopes that this “gene therapy” technique can be used to fight cancer in humans.1
Much is known about the genetic makeup of the mouse; it is probably the most commonly used mammal in genetic research. Scientists genetically engineer mice and breed them so that they develop human diseases that can then be studied or produce chemicals that can be used for the treatment of diseases.2
Much of our knowledge about the immune system has come from studies in mice.
Scientists are waging a continuous battle in the search for the best animal model for the study of AIDS, and much has been accomplished from research done with mice. Researchers have transplanted cells of the human immune system into SCID (Severe Combined Immuno-Deficient) mice, which lack their own immune systems. As a result, mice have dramatically increased their life spans. Experiments such as this have enabled scientists to apply information gained from mice to humans suffering from AIDS.
Because mice age much faster than humans, they are ideal for the study of human aging.
Researchers have found that immune system effectiveness and the ovaries decline with age similarly in mice and humans. This finding allows scientists to study mice in order to improve immune response in the elderly, reduce their chances of developing diseases and understand the decrease in their reproductive organ function.
Mice, along with other rodents, are used in product safety tests such as the repeated-dose chronic-toxicity test-which measures the effects of long-term exposure to a product, or the developmental and reproductive toxicity test-which measures the likelihood of infertility or effects on pregnancy because of product usage.
Scientists have used specially bred mice as hosts for viruses, infectious agents that require living cells in order to multiply and survive.
- Research with mice helped develop vaccines to counter influenza, polio, yellow fever and rabies.
- Research on mice has shown that the host as well as the agent plays a major role in viral infections.
TRANFER OF EMBRYOS
The successful transfer of human embryos is possible today because of experiments done with mouse embryos. This technique can be used to improve reproduction in domestic endangered species.
The research of inbred strains of mice is instrumental in understanding the harmful effects of radiation exposure and developing treatments.
1 Golumbek, P; Lazenby, A; Levitsky H; Jaffee, L; Karasuyama, H; Baker, M and Pardoll, D: Treatment of Established Renal Cancer by Tumor Cells Engineered to Secrete Interleukin-4, Science 254: 713-716, 1991.
2 Behringer, RR; Ryan, TM; Reilly, MP; Asakura, T; Palmiter, RD; Brinster, RL and Townes, TM: Synthesis of functional human hemoglobin in transgenic mice, Science, 245: 971-973, 1989. Ryan, TM; Townes, TM; Reilly, MP; Asakura, T; Palmiter, RD; Brinster, RL and Behringer, RR: Human sickle hemoglobin in transgenic mice, Science 247: 566-568, 1990.