Parabiosis: Assessing the Effects of Circulating Cells and Factors on the Skeleton

The circulatory system carries within it numerous types of cells, proteins, and other factors that are able to influence the local biology of tissues. Within this chapter, we present a protocol for parabiosis, a surgical model which results in shared circulation between two mice. Such chimeras have recently been used to probe the impact of age-associated changes in the circulation on skeletal, muscular, and neural biology. In conjunction with transgenic mouse models, parabiosis can be used as a tool to investigate the effects of specific factors on local tissues. Here we discuss our adaptation of this surgical procedure including technique details, pitfalls, and suggestions for optimization.