TABLE 2.
Animal models
| Species Used in Biomedical Research | ||
|---|---|---|
| Rodents | Rat Mouse Guinea pig Hamster |
|
| Nonrodents | Bird (quail, finch, pigeon) Rabbit Cat Dog (e.g., beagle) Ferret Sheep Cow Nonhuman primate |
|
| Nonmammalian | Zebrafish Drosophila melanogaster (fruit fly) Caenorhabditis elegans (nematode) Frog |
|
| Types of Animal Models Used in Biomedical Research | ||
| Type | Description | Example |
| Normal | Organisms without any observable deficits (can be used as controls) | Any |
| Negative/nonreactive | Organisms in which a certain disease does not develop | Opossum: resistant to rabies Rhesus monkeys: resistant to hepatitis B, Gerbils: resistant to radiation Rabbits: resistant to transmissible spongiform encephalopathy |
| Spontaneous | Animals with naturally occurring pathologic conditions, which mimic human disease | Rats: spontaneously hypertensive Doberman Pincher: von Willebrand disease Dogs: spontaneous model for prostate cancer, osteosarcoma, breast cancer, aging |
| Disease-induced/ experimental | Animal models in which the experimentally reproduced condition mimics a human disease | Rodent: induce diabetes with streptozotocin Rodent and nonhuman primate: induce Parkinson-like disease with neurotoxicant, MPTP |
| Genetic | Result of selective sibling breeding for a specific trait | Wistar Kyoto (WKY) rat for hypertension Athymic nude mouse: result of a natural mutation that lacks T cells |
| Genetically engineered | Organisms in which genes have been modified to delete or enhance gene expression | See below |
| Genetically Engineered Animals (Mouse, Rat, Primate) | ||
| Transgenic | Organism in which the genome is modified by the artificial insertion of foreign DNA (transgene) into every cell | 2D2 mice express T-cell receptors that recognize proteins involved in a multiple sclerosis model |
| Knockout | Organism in which foreign genetic information is expressed in the nucleus of embryonic cells, thereby inhibiting expression of certain gene(s) | Akt2 gene deletion to examine glucose uptake in diabetes |
| Knock-in | Organism in which generated specific mutations or exogenous genes are introduced into specific sites of a target gene through homologous recombination so that the expression of the gene knock-in may be tracked through the expression of a reporter gene | Erbb2 (HER-2) overexpressed in mice to examine its role in cancer |
| Humanized | Organism (typically a mouse) that carries functioning human genes, cells, tissues, and/or organs | Express human ACE-2 protein in mice to study SARS-CoV2 infection |