In vivo bioimaging using photogenic rats: Fate of injected bone marrow-derived mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) derived from bone marrow have the capacity for self-renewal and differentiation, and can give rise to cells of a muscle, bone, fat or cartilage lineage. Based on this potential and feasibility, MSCs are expected to be used in cell therapy for human diseases. Intriguingly, MSCs migrate to various in vivo locations, including injury and tumor sites. However, their cellular fate and distribution remain unclear. In this review, we first describe the potential of a photogenic transgenic rat that expresses fluorescent and/or luminescent proteins (e.g., green fluorescent protein and luciferase), and then focus on the characteristic migration of MSCs to injury and tumor sites. In addition, we will discuss an efficient delivery method for targeting the injured site. Synergized with modern advances in optical imaging, the photogenic rat system provides innovative preclinical tools and a new platform on which to further our understanding of matters concerning stem cell biology.