Animal model

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An animal model is a non-human animal that has a disease or injury that is similar to a human condition. These test conditions are often termed as animal models of disease. The use of animal models allows researchers to investigate disease states in ways which would be inaccessible in a human patient, performing procedures on the non-human animal that imply a level of harm that would not be considered ethical to inflict on a human.

In order to serve as a useful model, a modeled disease must be similar in etiology (mechanism of cause) and function to the human equivalent. Animal models are used to learn more about a disease, its diagnosis and its treatment. For instance, behavioral analogues of anxiety or pain in laboratory animals can be used to screen and test new drugs for the treatment of these conditions in humans.

Animal models of disease can be spontaneous (naturally occurring in animals), or be induced by physical, chemical or biological means. For example,

The use of metrazol (pentylenetetrazol) as an animal model of epilepsy^[1]
Immunisation with an auto-antigen to induce an immune response to model autoimmune diseases such as Experimental autoimmune encephalomyelitis^[2]
Occlusion of the middle cerebral artery as an animal model of ischemic stroke^[3]
Injection of blood in the basal ganglia of mice as a model for stroke^[4]
Infecting animals with pathogens to reproduce human infectious diseases
Using ionizing radiation to cause tumors
Genetically selected (such as in diabetic mice also known as NOD mice)^[5]
Various animal models for screening of drugs for the treatment of glaucoma
The use of the ovariectomized rat in osteoporosis research
Use of Plasmodium yoelii as a model of human malaria ^[6]^[7]^[8]

The increase in knowledge of the genomes of non-human primates and other mammals that are genetically close to humans is allowing the production of genetically engineered animal tissues, organs and even animal species which express human diseases, providing a more robust model of human diseases in an animal model.

Animal models observed in the sciences of psychology and sociology are often termed animal models of behavior.

In quantitative genetics, the term animal model is used to refer to statistical models in which phenotypic variance is compartmentalised into environmental, genetic and sometimes maternal effects. Such animal models are also known as "mixed models".

[edit] References

^ White HS (1997). "Clinical significance of animal seizure models and mechanism of action studies of potential antiepileptic drugs". Epilepsia 38 Suppl 1: S9-17. doi:10.1111/j.1528-1157.1997.tb04523.x. PMID 9092952.
^ Bolton C (2007). "The translation of drug efficacy from in vivo models to human disease with special reference to experimental autoimmune encephalomyelitis and multiple sclerosis". Inflammopharmacology 15 (5): 183-7. doi:10.1007/s10787-007-1607-z. PMID 17943249.
^ Leker RR, Constantini S (2002). "Experimental models in focal cerebral ischemia: are we there yet?". Acta Neurochir. Suppl. 83: 55-9. PMID 12442622.
^ Rynkowski MA, Kim GH, Komotar RJ, et al (2008). "A mouse model of intracerebral hemorrhage using autologous blood infusion". Nat Protoc 3 (1): 122-8. doi:10.1038/nprot.2007.513. PMID 18193028.
^ Homo-Delarche F, Drexhage HA (2004). "Immune cells, pancreas development, regeneration and type 1 diabetes". Trends Immunol. 25 (5): 222-9. doi:10.1016/j.it.2004.02.012. PMID 15099561.
^ Hisaeda H, Maekawa Y, Iwakawa D, et al (2004). "Escape of malaria parasites from host immunity requires CD4+ CD25+ regulatory T cells". Nat. Med. 10 (1): 29-30. doi:10.1038/nm975. PMID 14702631.
^ Coppi A, Cabinian M, Mirelman D, Sinnis P (2006). "Antimalarial activity of allicin, a biologically active compound from garlic cloves". Antimicrob. Agents Chemother. 50 (5): 1731-7. doi:10.1128/AAC.50.5.1731-1737.2006. PMID 16641443.
^ Frischknecht F, Martin B, Thiery I, Bourgouin C, Menard R (2006). "Using green fluorescent malaria parasites to screen for permissive vector mosquitoes". Malar. J. 5: 23. doi:10.1186/1475-2875-5-23. PMID 16569221.