Animal Models in Bone Research

Many studies of the response of isolated osteoblasts and osteoclasts to treatments exist. While such studies are informative, a reliable path to translating those effects into effects in humans is required, because of the skeletal intermediary organization that only exists in vivo. Bone cells function in vivo within the intermediary organizations of modeling, which controls bone growth and shape changes, and remodeling, which controls bone renewal during adulthood (Frost, Metab Bone Dis Rel Res 4:281–290, 1983). Modeling and remodeling govern how important tissue-level properties of the whole skeleton, such as bone mass, microarchitecture, strength, and calcium homeostasis, respond to treatment. Animal models are the lowest level at which the tissue-level intermediary organizations of modeling and remodeling can be examined. The purpose of this chapter is to give toxicologists an overview of some popular animal models of diseases of low bone strength, which can be used to translate basic research findings to the whole animal and human level. It focuses on osteoporosis and how various models not only provide in vivo skeletal behaviors that reflect tissue-level organizations found in adult humans but also can be applied to assist in understanding ways to prevent and treat various types of osteoporosis.