Rats
Rats are used extensively to test drugs and chemicals. After researchers administer a new medicine to rats they measure, e.g. blood pressure, kidney function, or the capacity of blood to coagulate.
Researchers observe what happens to animals during long-term treatment, e.g. by thoroughly reviewing organ function or by checking that tumours do not form. Regulatory agencies require this type of safety assessment in two different animal types. In practice rats are often one of these.
Rats are also used frequently in trials to study how a process normally functions, e.g. how blood pressure is regulated or what signals are transmitted by different cells.
There are also several different rat models for human diseases. Some strains of rats have, e.g. high blood pressure while others tend to suffer stroke. A particular variety of rat contracts diabetes and another type becomes obese. Yet another strain develops inflamed joints (arthritis) and is appropriate for that type of research.
Rats have been widely used for many years in research, so rat physiology and functions are well understood. The various centres in the brain have been mapped, and normal values for kidney, liver, and heart function can be found in the literature. Hence, researchers find it easier to continue using rats instead of other animals that are not as well documented.
Different drugs can affect a rat´s brain. Hence, rats can develop conditions reflective of certain psychiatric disorders in humans.
Rats are also used to study skeletal growth. The human skeleton grows in length within particular zones at both ends of each bone. After we reach a certain age, the growth zones close off so the skeleton can no longer grow. Rats have similar growth zones, but they never close off. Therefore, it is possible to study bone growth during the entire lifetime of a rat.
Rats are also used in some plastic surgery procedures when surgeons need to practice suturing nerves and thin blood vessels.
An important characteristic of rats is that they adjust rather easily to humans, i.e. they are easily socialised. Animals accustomed to being handled by humans become less stressed, e.g. while taking blood samples. This lowers the risk that stress hormones might affect the blood sample.
Compared to mice, it is easier to teach rats to perform certain tasks, e.g. to press a peddle to get a reward or to find something in a maze. Hence, rats can be suitable for studying memory functions and the effects drugs or other agents.
Rats are also used frequently in trials to study how a process normally functions, e.g. how blood pressure is regulated or what signals are transmitted by different cells.
Different models
There are also several different rat models for human diseases. Some strains of rats have, e.g. high blood pressure while others tend to suffer stroke. A particular variety of rat contracts diabetes and another type becomes obese. Yet another strain develops inflamed joints (arthritis) and is appropriate for that type of research.
Rat physiology is well documented
Rats have been widely used for many years in research, so rat physiology and functions are well understood. The various centres in the brain have been mapped, and normal values for kidney, liver, and heart function can be found in the literature. Hence, researchers find it easier to continue using rats instead of other animals that are not as well documented.
Different drugs can affect a rat´s brain. Hence, rats can develop conditions reflective of certain psychiatric disorders in humans.
Rats are also used to study skeletal growth. The human skeleton grows in length within particular zones at both ends of each bone. After we reach a certain age, the growth zones close off so the skeleton can no longer grow. Rats have similar growth zones, but they never close off. Therefore, it is possible to study bone growth during the entire lifetime of a rat.
Rats are also used in some plastic surgery procedures when surgeons need to practice suturing nerves and thin blood vessels.
Easily socialised
An important characteristic of rats is that they adjust rather easily to humans, i.e. they are easily socialised. Animals accustomed to being handled by humans become less stressed, e.g. while taking blood samples. This lowers the risk that stress hormones might affect the blood sample.
Compared to mice, it is easier to teach rats to perform certain tasks, e.g. to press a peddle to get a reward or to find something in a maze. Hence, rats can be suitable for studying memory functions and the effects drugs or other agents.
Text: Karin Nordin
References
- John Bräutigam, veterinarian, Swedish Board of Agriculture
- Helena Elofsson, Fil. Dr. Zoology, Swedish Board of Agriculture
- Anne Halldén Waldemarson, University veterinarian at Karolinska Institutet
- Torgny Jeneskog, University veterinarian at Umeå university
- Karl-Gustav Jacobsson, University veterinarian at Uppsala university
Responsible for content: Mats Ulfendahl, Secretary General of Medicine and health, Swedish Research Council.
Editor: Peter Tillhammar, Swedish Research Council. Contact: Send email to the editorial staff.
Editor: Peter Tillhammar, Swedish Research Council. Contact: Send email to the editorial staff.
