**1. Introduction**

The aim of this book chapter is to highlight the fact that regenerative medicine and tissue engineering have important consequences for animal research and can be exploited to develop powerful animal sparing *in vitro* models. The main objective of the authors is to encourage researchers to consider designing, developing, utilizing and exploiting biomimetic alternatives to *in vivo* animal models. This chapter will focus on some of the most popular *in vitro* models that have been developed for skeletal muscle and articular cartilage. Refining these animalsparing models will advance tissue engineering and regenerative medicine and may replace animal models and significantly reduce our dependence on animals in research. Over the last few decades, a number of different animal models have been developed to support preclinical and clinical research to address hypothesis or curiosity driven research. However, many of the currently available animal models are not suitable models for human disease. 'Evidence-based medicine' refers to the ability to locate, critically appraise and incorporate evidence into clinical practice. This important branch of medicine seeks to assess the strength of evidence of the risks and benefits of treatment (or lack of treatment) and relies on well-established and reliable models to facilitate the research that underpins the decision-making process. Clinical research and evidence-based medicine therefore rely on the availability of reliable model systems that can be used for translational research. Using *in vitro* culture models eliminates some but not all of the problems associated with clinical research with human subjects and animal models of disease. In many cases culture models help to overcome barriers and allow researchers to gain a better understanding of disease pathogenesis, characteristics and responses to treat‐ ments. This chapter will focus exclusively on animal sparing *in vitro* models of muscle and joint tissues that have been developed to mimic these musculoskeletal structures. Many of these models are well established and possess similar morphological, histological, biochemical

© 2013 Mobasheri and Lewis; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

and molecular characteristics of muscle and joint tissues *in vivo*. These *in vitro* models allow researchers to perform original, hypothesis-or curiosity-driven research without using animals while still accurately mimicking musculoskeletal tissues in real life. *In vitro* models also enable screening for new drugs to treat musculoskeletal diseases in a more efficient and cost-effective way such that real progress is achieved more quickly.
