Animals are used in translational researches because of their similar physiology to humans. They share genetic, behavioral and biochemical activities to humans. In this article Anderson and winter. (2017) highlighted the use of animals in the research fields and talked about applications where animal models replaced humans to find a cure to certain diseases. William Russell, a zoologist, and Rex Burch, a microbiologist introduced the aspect of the 3 R's as ethical conduct to be adapted in a lab setting.
Reduce the number of animals used.
Refinement which uses methods that avoid animal suffering.
Replacement of animals by other organisms or microorganisms.

 http://dx.doi.org/10.1590/0001-3765201720170238

Citation: Andersen, M. L., & Winter, L. M. (2017). Animal models in biological and biomedical research-experimental and ethical concerns. Anais da Academia Brasileira de Ciências, (AHEAD), 0-0.