**7. Conclusion**

Despite decades of research to eradicate the disease, RA remains one of the most prevalent diseases within its scope and even with a well-defined and unknown etiology. Currently, animal models continue to be an effective and necessary tool for the generation of knowledge on most autoimmune diseases including RA. Currently the animal models are still the main link to understand how the immune system attacks its own components (cells or organs), as well as the evaluation of molecules with therapeutic objectives.

Animal models, inducible (CIA models, passive antibody, or streptococcal wall transfer) or spontaneous (knockout mice), have been shown to be useful in understanding unknown processes. For spontaneous models, it is difficult to perceive the mechanism by which the disease in which the therapeutic compounds are evaluated is triggered. In the same way, no animal model shows all the characteristics of the disease and the route by which the therapeutic agent is introduced can generate variation in the results, so this information should be complementary with the evaluation of more routes of administration. It is envisaged that the generation of new molecular techniques will help to determine the complexity of the functioning of RA as well as to evaluate the different routes of administration of therapeutic compounds pending the attainment of low toxicity and wide benefit therapies that are determined and used for clinical phases.
